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Buying Used: The Ultimate Isuzu D-MAX 2012-2020 Buyers Guide

17 Mar 2022
Buying Used: The Ultimate Isuzu D-MAX 2012-2020 Buyers Guide

Isuzu Ute Australia’s D-MAX 2012-2020 Buyers Guide – Buying Second Hand

The recently superseded RT series of Isuzu Ute Australia’s D-MAX, was a ute owing its fortunes largely to one ace in its stack of cards, an engine borrowed from the Isuzu truck range and noted for its longevity and ease of service. It has never been a fire-breather, always delivered to the Australian market in a very conservative state of tune, with an eye to clocking up big kays.

Once upon a time, diesel engines were rated against a half-million-kilometre service benchmark, (that is before needing some serious spanner work on them), Isuzu’s 4JJ1-TC is one of those motors. That is one of the reasons that independent mechanics, when asked “what ute should I be buying second hand”, the answer usually comes back… D-MAX.

Some History and Product Sharing

The precursor to this model was initially sold into Australia as the RA Rodeo, under a product sharing arrangement with Holden/GM between 2003-2008. Then, as a result of a minor divorce, because the rights to the Rodeo name were in dispute, the partners went their separate ways, Holden rebadging with the Colorado nameplate and Isuzu Ute Australia stepping into the local market with the D-MAX brand for the first time.

I remember all too well being at the launch of the Colorado in the Victorian Alps in 2008 and hearing the Holden marketing team crow on about how they were about to unseat Toyota and the Hilux from the top rung. Apparently, they knew the 4WD world back-to-front here in Australia. History tells us that that went well didn’t it?

2008 Holden Rodeo

2008 Holden Rodeo

It’s that same marriage of convenience that blighted the new 2012 model as GM’s inputs were compromised by the parlous state of their finances thanks to the GFC. In case you can’t remember the Global Financial Crisis back in 2008, the world suffered a major financial meltdown and near collapse, thanks to some very greedy bankers in the USA.

GM was under the pump, as its stock price had plummeted to barely $2/share and owing billions to its financiers, as well as its health/super fund for employees. An initial $5B injection from the US Government saved the day (as part of a larger $49.5B rescue package for the auto industry), as GM was one of the businesses deemed too big to fail and was about to declare bankruptcy.

Stitching together a new vehicle costs significant coin (reportedly in this case $2B) and the spend was kept on a knife-edge with that GFC background and thus hindering the full sales potential of the vehicle, with a specification, performance and features list that was shy of competitor brands.

Luckily there was a clear distinction between the D-MAX and the Colorado. Maybe Isuzu knew the writing was on the wall for Holden?

Despite being built in the same country (Thailand) and sharing the same basic architecture, it was only the interiors that had a close familiarity. No body panel was the same, and the engines and transmissions were distinctly different.

2014 Holden Colorado

The Colorado used a 2.8L four-cylinder VM Motori (GM subsidiary in Italy) turbo-diesel called Duramax with a rubber timing belt Vs the D-MAX’s 3.0L four-cylinder Isuzu 4JJ1-TC with a timing chain. Chains don’t tend to break, whereas a belt will, and needs to be replaced at 10 yearly or 100,000kms intervals. That’s a service sticking-point with Colorado and one of the many things that put the brakes on mass sales until Holden’s demise.

The RT Euro 4 - 2012-2017

Originally offered in three body styles, single-cab, space-cab and crew cab and in the trim levels of EX, SX, LS-M, LS-U and LS-T, there was a D-MAX for all tastes and budgets. Prices in 2012 at launch for a poverty-pack EX single cab 4WD manual kicked off at $27,200 plus on-roads and peaked with the LS-T crew cab 4WD auto at $51,700 plus on-roads. Warranty offered a 5 year/130,000kms period with roadside assistance.

Isuzu D-MAX LS Terrain

The 2012 RT was a major departure from the RAs, running a strut IFS (Independent Front Suspension), a shock and coil spring combo setup in the front end instead of the previous model’s torsion bar arrangement. This afforded a much better ride than before and a greater opportunity to modify for off-roading and following everyone else’s script, for modern front suspension design.

New Safety Electronics – ABS with ESC/TRC/EBD/BA

It also introduced a new suite of safety electronics and added to the existing ABS (Anti-Lock Braking) system employed in the previous model.

For the first time on an Isuzu were ESC (Electronic Stability Control) and TRC (Traction Control) along with EBD (Electronic Brakeforce Distribution) and BA (Brake Assist). Whilst the on-road functions of these safety features were as good as their peers at the time, TRC off-road was woeful.

Where other manufacturers like Toyota and Mitsubishi had brake traction-control systems that were tuned to recognise the engagement of LOW range and employ another, lower engine-speed algorithm (around 2-2,500rpm on-road in HIGH range Vs 1,100-1,250rpm in LOW range), D-MAX had only the HIGH-range, on-road state of tune, making it useless in preventing wheel-slip in any off-road setting at slow speeds. Anyone telling you otherwise is pulling your leg!

CV Driveshafts, Differentials and Traction Issues and Fixes

There is no doubt that this was a major contributor to the oft-reported failure of CV (Constant Velocity) joints in 2012-2020 D-MAX and further exacerbated by the omission of a rear-axle diff-lock.

The issue can be driven around with a very conservative driving style, but even then, you might suffer an unexpected failure, with seemingly no rhyme or reason when in 4WD.

In my personal D-MAX I eliminated most of the risk by installing an ARB Air Locker in the rear and electing to use it whenever there was any chance of a cross-axle loss of drive. Prior to that I had two fail and in circumstances I’d describe as pretty ordinary.

Something else that’s been observed is that the output centre from the front diff doesn’t align with the centre of the hub that the CV equipped driveshaft has to span. Offset and forwards, the hub assemblies are presenting a challenge to the CVs they likely don’t like. A straight and flat driveshaft presentation in the first instance is less likely to bind, when the time comes to articulate, thanks to less aggressive angles.

If you are going 4WDing on a regular basis, you are going to need a rear diff-lock (luckily on the new 2021 D-MAX both of these issues have been addressed). The aftermarket offers a few choices, but I would not be installing one in the front to add even greater stress, and especially so if the suspension has been lifted.

The maximum safe lift on a D-MAX of this generation is a nominal 2”, which a reliable suspension maker will deliver in the front end as something more like only 40mm, tops. If you are busting your chops for a 3” setup you will be bitterly disappointed. It will be a pig to drive and set you up for a pogo-like ride on a stepped trail that will induce CV failure.

Some would argue that a diff-drop will help on vehicles that have been lifted, restoring CV angles to their original state. It will certainly help in retaining some precious “droop” travel, but I’ve seen diff-dropped D-MAXs still break CVs when their owners have been a little too aggro with the go pedal.

Something else that might break, apparently, are the differential centres?

The forums report front and rear diff failures in a few vehicles and again, lots of finger-pointing, but precious-little detail on the event. I know from personal experience that ours have been solid. I also know that hard-core off-roading with really big wheels places ridiculous mass loadings on driveline components they were never designed to cope with. I also wouldn’t mind betting more than a few of these breakages were due to D-MAXs being left in 4WD, on resumption on the blacktop, after a workout! Wind-up kills differentials.  No-one is going to admit to making that mistake!

Another common “fix” for the traction inadequacies is to go back in time and retro-fit an LSD (Limited Slip Differential) centre from the previous generation RA Rodeo/Colorado. It’s a cheap option that, provided the LSD is shimmed-up nice and tight, will reward with grip, where previously there was none.

That is when you can also learn the art of “poor man’s traction-control”, levering up the handbrake at the critical traction-loss moment, to induce the LSD’s friction plates to bind and brake the spinning wheel, then redirect that lost torque across the axle to the wheel that had some grip.

Euro 4 Engine and Transmissions

The engine/transmission combo in this first-generation RT, let us call it the Euro4 spec version, was the aforementioned 4JJ1-TC “Hi-Power”, with the modest outputs of 130kW and 380Nm and coupled to either a five-speed manual or automatic.

I owned the manual in a D-MAX and the auto in an MU-X. Both have proven to be solid transmissions, despite my delivery-day misgivings about the ute’s clutch.

Back in 2014 when I picked mine up, I remember that the clutch action was just weird, with a high-pedal-travel/friction point to get going. It didn’t feel right and compared to others I’ve driven since (and that’s plenty), it was odd. Despite regular complaints at service intervals, it’s had the last laugh, because now, and at 150K, with tonnes of hard work, it is still going!

The auto was made by Aisin in Japan and like the manual, offers four direct gears and one overdrive, plus a sports-shift manual-mode. The torque convertor could lock up on second, third, fourth and fifth gears. It also offered grade-logic and would drop to lower gears (typically third) in descending hills at highway speeds to limit overspeed moments where you would usually be tapping the brakes.

Going Off-Road and Engaging 4WD

In LOW range you can only access the first four gears, thus saving the box from torque-overload and possible failure, if it were to use the fifth speed. As it’s an overdrive gear it’s not designed to do that in LOW range. That trims some desirable ground speed momentum in sand when in LOW, compared to the manual, so to compensate, you’ll likely need to air down those tyres some more.

LOW range reduction in LOW for both auto and manual were 2.482:1, HIGH range 1.000:1. Not earth-shattering but respectable

Credibly, for off-road use, you could manually start the auto in second gear in sand or mud and know it would stay there until you stirred the pot. So many times with other makes I have experienced shifts back into first, when you don’t expect it or asked for it, leaving you short on ground speed at a critical moment.

Traction control is a full PITA in D-MAX on sand and in mud for the reasons mentioned earlier.

In HIGH range you will want to find the ESC button and do a long button depress, around seven seconds, so you can sequentially turn off both TRC and ESC. Don’t be surprised to see the ESC light aglow when you select LOW range.

As ESC is a high-speed function of the car, it is not needed, as the vehicle assumes you will be travelling slower than 50km/h. You will still need to turn off TRC. Go on, push the button! Each time you turn the ignition off, all the safety Nannas will come back on and need another button depress to shoo them away. You’ve been warned.

The auto and manual spread of gears were reasonably well-matched to intended use and highway speeds and suffered only marginally with the installation of bigger wheels. LOW range descents with legal 32” fitments were still credible and on the highway the vehicle could still muster enough grunt to overtake safely. The speedo became accurate too.

Go for bigger 33” sizes and you might enhance your manhood, but you’ll kill it in the motivation stakes, it will be slower than a wet week. You’ll also affect the fuel economy, and braking, as the brakes weren’t designed with that big a wheel mass in mind, break more CVs and run downhill in LOW range faster than likely comfortable.

If ever you need a tug out of a bog you will run foul of the non-rated tow points on the vehicle’s front chassis rails. There are two closed loops that will make a static tow do-able, but Isuzu won’t be signing off on a snatch-strap recovery off them, when they cannot see what you are about to attempt.

Better to augment them with a couple of dedicated recovery points. On both Wilson vehicles we elected to use ARB’s bespoke items, triangulated into the chassis rails and very secure.

Transmission Temperatures

Watch your transmission temps in undulating country and especially when towing or slogging through kilometres of soft sand though. The Aisin auto isn’t a big fan of gradients or loads and will drop gears without too much provocation which gets a bit tedious listening to the change in engine speed and watching for the transmission temperature light to appear.

Despite auto transmissions being “sealed” for life these days, I don’t buy it. If you are a regular tower, get into the habit of going to an auto-trans specialist and get them to change the fluid and filters. You might be surprised just how grungy the fluid gets.

Dealers and the handbook recommend leaving it in drive and letting the transmission work it out, but in my experience that’s a recipe for overheating the box. Towing into a Force 10 gale or up and down a hilly region on a hot day will take its toll. Use of the manual mode will get you a better result at times of high load and you can help it further by investing in a quality transmission cooler.

Maintenance and Operational Recommendations

I should also mention leaky rear main seals. When they leak it’s usually more a weep, mine has been that way for a couple of years and I didn’t bother getting it seen to as it wasn’t going to get any worse. Others might beg to differ, but I’m reliably told it is more cosmetic than terminal.

Owner maintenance is to be encouraged and I regularly would drop the oil, spin on a new oil filter and blow out the air filter, but a word of warning with the airbox on D-MAX. When you swap the paper element out with a new one, or service it and close the airbox, there are two retaining loops (plastic) at the back of the box, that receive two tongues to positively locate the lid in the right spot.

If you are a bit ham-fisted, it is really easy to snap the loops, thus denying a snug fit and dust ingress is a real possibility. I managed to Superglue a broken loop on both the D-MAX and MU-X and, with careful reinstallations since, I am pleased to report it is hanging in there.

Luckily for those into water sports, D-MAX came pre-fitted with diff and gearbox breathers and breather tubes that extended up and into the bodywork and terminated at a high point by the airbox (front) and chassis (rear).

The 4WD system is a basic part-time jigger. Part-time 4WDs will NOT sustain driving on hard surfaces (bitumen/concrete/paving), wet or dry. The more corners you corner, the greater the chance you’ll break the front end. HIGH range 4WD engagement on gravel roads should be encouraged as it is much safer than 2WD will ever be.

 There are three positions, 2H = 2WD (rear wheels only) in HIGH range, 4H = 4WD in HIGH range and lastly 4L = 4WD in LOW range. It’s a shift-on-the-fly arrangement, 2H > 4H can be done on the move at speeds up to 100km/h, whilst 4H > 4L is only achievable whilst stationary and with the main shifter in N (Neutral) in the auto. In the manual you didn’t need the clutch.

If you make all your HIGH range engagements on the move, you’ll get a positive result, either going in, or coming out of 4WD and confirmed with a dash display. LOW range can be a little a little hard to find at times unless you’ve got all your ducks lined up (straight steering, in neutral and with HIGH range already engaged). You’ll know when you get it because there’s a pronounced clunk from the under-gubbins. Another dash light will confirm it. Trying to swing straight from 2H > 4L whilst stationary will likely reward you with a flashing 4WD light and no hook up with the front differential, so get the HIGH range engagement done beforehand. Then it should be a snip.

Towing with D-MAX

Towing was not a strong D-MAX suit in my humble opinion. Despite the engine’s flat and linear torque curve there simply weren’t enough torques.

On stock wheels, acceleration when towing was acceptable (remember at the time Ranger and BT-50 and the Colorado offered 470Nm of torque Vs 380Nm in the D-MAX), but with your new set of taller treads, it’s a slower process and compared to opposition makes of the day, it is not a ball-tearer.

Some owners have opted to reflash their fuel management system or use a plug-in chip to change the fuel metering parameters, delivering more fuel and power.

Whilst the engine is inherently strong, going down this path is not without some risk.

Over-fuelling and higher exhaust temperatures might make a hand grenade of your 4JJ1-TC, so I wouldn’t do it. I can tell you that doing a muffler-delete is worth doing on these pre-DPD models, as the vehicle is a lot crisper in accelerating from a standstill and generally more responsive. That’s a cheap mod and adds a subtle sporty burble to the exhaust note, that the child in me appreciates!

The majority of my towing was done with Kimberley camper trailers with around 1,500kgs ATM (Aggregate Trailer Mass). A couple of times I towed caravans at near capacity (that’s 3,500kgs) and found it challenging. My personal view is that none of the utes sold in this country can safely pull anywhere near their maximum stated load and it should be avoided at all costs. There are simply not enough gee-gees for safe overtaking, not enough brakes to stop and suspensions that are chronically underdone for carrying heavy loads.

Suspension Issues

Talking of suspension, the rear live-axle uses leaf springs with shocks. The carrying capacity of the stock setup will likely be unsuited to your needs and like the front, needs to be replaced if your want is to four-wheel-drive or tow. The vehicle sits too close to the ground in standard trim (the brochure says 235mm) and will sag with any load. D-MAX sidesteps are especially vulnerable on ramp-over angles, when you will find that plastic and aluminium don’t usually respond to trackside repairs. Take them off.

Cheap fixes have included add-a-leaf helper-springs or airbags. Neither are any good. Airbags in particular increase the risk of chassis failure by point-loading the rear rails at a place they weren’t designed to take force, a bit like riding on the bump-stops all the time. Additionally the fitment of weight-distribution hitches was something that Isuzu Ute Australia frowned upon, because the torque-leverage added to the towbar assembly encouraged failure on a big enough bump.

The only reliable fix is to take the vehicle to a suspension specialist and replace the lot with a spring set-up calibrated for your realistic loads. We sell excellent suspension kits for RT D-MAX, in-particular our Dynamic Tune range, that you can find out more about here.

Do not go down the path of a GVM upgrade!

Learn to take fewer items and pick a smaller caravan and ignore the cries of foul from your partner.

GVM upgrades create an overly stiff and rigid suspension that’s not compliant, inflexible off-road and likely to cause fatigue in axle, driveshaft components, chassis and body metal, especially so when driven with overinflated tyres. You have just used up that last 10% of capacity that the maker has kept in reserve to prevent this very thing from happening.

Here at the Loaded 4X4 Store we have crafted suspension systems that are tuned for D-MAX comfort and will carry sensible loads and you can access that information here.

Brake Issues

Brakes were nothing special either, my pet hate with utes, is a drum-brake back end. The D-MAX ran ventilated front discs of 300mm diameter with twin-piston calipers which were okay, but the rear 295mm drums were pathetic. In highway use you might extract reasonable shoe life, but in my experience, I suffered my typical drum-brake woes of constant shoe replacement (bi-annually) due to trackside debris infiltration and regular adjustments were necessary to preserve a high-pedal and short handbrake stroke. Note to all makers, you need to fit discs front and rear please, because this stuff is rubbish and requires over-servicing!

Plenty of owners would also complain about what seemed to be front wheel bearing screams. It was in fact the front hubs needing a spray of magic-lube, Lanolin the can of choice. Dust will infiltrate the hub assembly, and that, and time, will dry the assembly out. A quick squirt usually fixes it.

Inner Guard Cracking

Let’s talk about the body metal.

There are a few reported failures of engine bay inner guards, where cracks appear and then require a serious dismantling of the vehicle (that’s engine out) in the crash shop for repair. Some fixed under warranty, others not.

Lots of finger-pointing has been directed at aftermarket accessory fitment, especially bull-bars and doubly-so bull-bars with winches, plus twin-battery setups and all the other junk that 4WDrivers like to add to a vehicle’s engine bay and near regions. Lifted suspensions have been cited as a cause as well.

Other blame has been attributed to the failure of rubber body mounts and a Facebook-fix is the use of Colorado rubbers instead of the Isuzu ones. Dunno about that, but I am firmly of the opinion that the failures are more than likely a combination of the vehicles regularly carrying medium-heavy loads, driving over repeated corrugations, and at too high a speed, and the gotcha moment – with overinflated tyres!

The bull-bar isn’t necessarily the culprit as it is attached to the chassis and the chassis is designed to flex, if it didn’t, it would crack. If the bull-bar was installed with insufficient clearance between bumper and guard, then there’s a chance it might be a contributor if it had been belting the living daylights out of the guard. That’s unlikely to happen as you’ll hear it and get it rectified quickly. I know plenty of people, like me, who run the likes of an ARB steel bull-bar (no winch), the heaviest, and have had no trouble at all.

Typical pressure statements on this vintage D-MAX and seen on the placard, hovered around the 200kPa/29psi mark for the fronts and up to 250-280kPa/36-40psi on the rears. Notice I said “up to”.

Despite my ute being heavy with a steel bull-bar, side rails, steps and UVP, along with a steel long-range fuel tank and all my training gear, most of its life on the bitumen it ran 210kPa/30psi front and rear when light and the backs bumped up to 250kPa/36psi when towing or heavy. On the dirt I slow down by 20% and drop the same margin in tyre pressure, the nett result is a more-comfy ride, less metal-fatigue-inducing trackside harmonics and no tyre failures. You ought to try it sometime.

Oh, and that was on quality light-truck tyres as well!

I mentioned UVP in the last paragraph, that’s Under Vehicle Protection, AKA, bash-plates.

The UVP under this generation is flimsy with maybe 1.5mm pressed steel, offering only rudimentary protection against bumps and scrapes. Better to seek out some aftermarket remedy for something substantial. On my old jigger, I used ARB’s kit and it has copped a hiding. If you are about to pull the trigger on a new 2022 D-MAX or MU-X, go to the Loaded 4X4 Store as we will have our versions for sale in the second quarter of 2022.

The Tub

The ute tub is a generous size but blighted by a lack of tie-down points. Isuzu supplied a loop in each rear corner, but they were set low and impractical for my loads. I fixed that after applying a spray-in urethane Rhino Lining (as I loathe and detest plastic drop-in liners), which settled the loads from sliding around and coupled to Nissan’s ingenious Utili-Track system. Drilling into the tub to install some nutserts, gave me my fixing points for the D40 Navara’s aluminium Utili-Track rails, located in the floor between ridges. With the adjustable cleats installed, I can secure any load with a ratchet strap and know it won’t come adrift.

Trying to dampen the ingress of dust through the tailgate gaps in a ute is an almost impossible task. I did try a kit from Brown Davis that comprised some rubber door seals and UVA foam blocks and it helped, but you will just have to live with it.

Speaking of tailgates, one of the BEST modifications you can make to a D-MAX is installing a gas-strut setup and replacing the hinged metal straps. The struts take all the lifting pain out of tailgate use. Must-have modification!

Interior Comfort

The interior of the D-MAX was comfortable, but littered with a fair bit of hard plastic. The ones that annoyed me were where I rest my elbows, the top on the centre console bin was rock hard and the upper door trim was equally unforgiving.

The upper dash surface also featured a cubby-hole with a lid for small nick-nacks, which in theory was a great idea, except the lid would never open, no matter how many times you’d stab the button. I mention it because it was both hilarious and frustrating and all in the same moment.

The seats were reasonable for three hours in the saddle without a break and not leaving you looking like a cripple, with plenty of fore/aft and rake adjustability. The steering wheel allowed only tilt, no telescope.

The rear seat leg space was okay unless you were tall, the seat a little upright for my likes and the seat base lacking deep-foam cosseting for your bum cheeks. The rear seat bases were foldable and that enhances the practicality of a D-MAX as the space was often the location point for a 60L fridge when working away. There are also a couple of cubby holes under the floor where the seat base would normally rest, one side holding the bottle jack and tool roll.

Plenty of owners reported that the stereo/navigation and Bluetooth provision was pretty ordinary and phone reception through the speaker for the driver and microphone clarity for the other party at the end of the line were, at best, hit and miss. Navigation was also slow. Replacing the system with a popular aftermarket brand will likely get you a better result.

A/C Issues

One major fly in the ointment in the comfort stakes is the air-conditioning.

Any D-MAX of this vintage is likely to suffer evaporator failure. There’s some pipework that gets a little too close to the firewall and on corrugations will rub and fracture the assembly. There are other reports that irregular cabin filter change-outs will lead to internal corrosion and weirdly mysterious pin-prick leaks that could be manufacturing fails, leading to an escape of the gas. The solution? Pull out the dash. Luckily a revised part, once installed, should eliminate future problems.

My D-MAX has had this done twice now and thanks to Isuzu Ute Australia, all under warranty. You probably want to be sitting down when you hear the quote if you’re fixing it out of your own pocket. Likely near a day’s labour.

Alternator Issues

Might also mention that the 90amp alternator is vulnerable as it sits low and at a point where water and sludge can get to it. I nearly lost one in the first session I ever did in mud, roughly a year old, and noticed when it started screeching and the charge light came on. I managed to tip about three litres of cold drinking water through it whilst it was running and miraculously it flushed out the grit and came good.

It finally succumbed to mud recently and had to be replaced, the non-genuine part cost around $450 and a couple of hundred to install. I figured that was reasonable after nearly seven years and living a very dirty existence.

Sticker Specials

During the life of this series there was a variant spun out of the top-of-the-tree LS-T, to appeal to folk who like some bling. Initially launched in limited numbers in 2014 and called the X-Runner, it offered gun-metal painted 17” wheels, some lairy GT stripes on the bonnet and tailgate and front flanks, plus some red coloured inserts in the seats and door trims, a red Isuzu grille badge and a black painted tub sports bar and plastic tub liner.

It was the true embodiment of a sticker special, as mechanically it was the same bag of tricks. There were just two colours, Pearl White and Mica Black and the 660 examples sold pretty quickly.

It was repeated again in 2019 in the RT series, again limited in numbers to just 645 examples in Pearl White and the new Magnetic Red. The wheels grew an inch to 18” and again painted, this time in a matte black. It was another sticker special. Yawn.

Wheels and Tyres

16 x 7” fitted with 245/70R16 AT – replace with LT245/75R16 120R or LT265/75R16 123R

17x 7” fitted with 255/65R17 HT – replace with LT265/65R17 120R or LT265/70R17 121S

The RT Euro 5 - 2017-2020

As before there were three body variants, single cab, space cab and crew cab and in the same trim levels of EX, SX, LS-M, LS-U and LS-T. Prices, as you would expect were on the rise, with the EX single cab manual 4WD costing $34,800 plus on-roads and the LS-T crew cab auto 4WD costing $54,200 plus on-roads. 

In 2019 warranty was expanded to 6 years/150,000kms with roadside assistance and IUA introduced a 7 year capped price service regime where they claimed 7 years of regular service would only cost $3,600.

Euro 5 Engine and Transmissions

In 2017, the major news story was an update to a new Euro 5 compliant engine and now known as the RT Euro 5 series and you’ll know if you’ve got that one, because when you lift the bonnet, you’ll see a bright red intercooler hose near the airbox.

With the hose comes some more go, torque output enhanced marginally to 430Nm. It was definitely more-sprightly, but that is likely more to do with the gearbox, because you get six speeds to choose from in both auto (called Rev-Tronic) and manual and first was lower, the manual getting a gear-speed indicator in the dash display in case you forget. Additionally with the new manual it is worth noting that use of LOW range required a clutch depression, something not required in the past with the previous five-speeder.

The extra gear in the auto sounds like a good idea, until you get it on the open road…

I hate a gearbox that hunts and this one carried on like a pork-chop, up and down like a yo-yo, so luckily there was a transmission software revision that calmed it down a bit, but it was not Aisin’s best bit of work. Isuzu’s weren’t alone at the time because I remember driving the same gearbox in Prados, Fortuners and Hiluxes and they were all blighted the same way.

DPD and Revised Turbo Issues

The other “improvements” were a DPD (that’s code for Diesel Particulate Diffuser) that has been reasonably reliable, but I wish I could say the same for the then, new, variable vane turbo. It was a dud.

It’s a Mitsubishi unit and whilst I don’t have a beef with that company’s 4WDs, this component was flawed. Under acceleration (like in the three failures I witnessed, when overtaking other vehicles), the vanes get stuck open, the blower goes into over-boost (apparently around 30psi) and that triggers limp-home mode, with its reduced engine speed to protect the motor from further harm. It always happened to me when I was on the clock and inconvenient.

Another common failure with them is likely due to swarf left behind in the machining process and incorrect tolerances between the main turbo-shaft, the vanes and its body, creating an imbalance that presents like the Sirens in Homer’s Odyssey.

It will be a throwaway and initially was being replaced with an identical new unit, before it was realised it was a turbo design and manufacturing issue. It is not uncommon to have some owners have to suffer three or four replacements until they get the revised version (looks the same, different part number) that fixes the problem. Luckily, this is a simple warranty job that will be honoured reliably and you’ll know when it’s going to occur when it starts to sing. Or it just goes pffft. Like when you try overtake that truck. It is also not kilometre-dependent. Could be new, or a year or two old, but it will fail.

The DPD (Diesel Particulate Diffuser) system is pretty reliable, but it will play up if you mostly do short hops around town. On longer journeys and at highways speeds with the exhaust temperatures up, it will be as happy as Larry, passively regenerating the diffuser. On short, stop/start runs, it might give you a bit of grief. You can watch its progress on a dashboard screen with five bars indicating how choked the diffuser is. Active regeneration is automatic and you’ll know when it is on, as the car gets a bit stinky with some additional heat wafting around, plus you’ll note a slightly increased idle speed.

The system is akin to a catalytic convertor in a petrol engine car. By adding more fuel and raising the engine speed and exhaust temperatures, the “burn” as it is called, turns any soot or PM (particulate matter) into harmless ash, that escapes out the exhaust pipe.

The DPD box fortunately is located up high in the engine bay and won’t start scrub fires like other makers who’ve placed theirs under the vehicle. They get hot and any combustible material around them will… combust!

I have learnt that the DPD pressure sensor might start playing up around the 100-150K mark. The sensor measures the saturation of the diffuser. As the PM from the diesel combustion process accumulates in the diffuser, it creates a pressure imbalance between the inlet and outlet sides of the exhaust. The restriction is noted by the pressure sensor which then triggers a burn. If the sensor fails, the burn doesn’t occur, choking the engine and promoting another limp-home response and a visit to the service centre for rectification. Fortunately it is a relatively simple fix, being a plug-in part.

Flash Interior

Interior changes were limited to some fabric changes on the seat and stitching and a new circular dash gauge display, plus on the up-spec models a padded centre console-top. Revised audio units provided better phone connectivity and sound quality, but still far from perfect. A reversing camera was standard across all the LS variants and a USB charging point can be found behind a silly rubber flap that you will need a sharp point to flip open. Why?

Hill Descent Control but no Rear Diff-Lock

Added to the ABS suite of braking aids was HDC (Hill Descent Control), an autonomous (once engaged) downhill braking system.

A lot of folk unfamiliar with 4WDing can get themselves into a bit of a tangle off the beaten track when they adopt the “D for Dumb” method of off-roading. That is, leaving an automatic in Drive and assuming the transmission will look after every eventuality on the trail. Of course, use of Drive in a descent is not without some challenge, as the vehicle will want to pick up speed, shuffling up through the gears unless the footbrake is applied.

Heading downhill at a million-mile-per-hour is scary, so with HDC activated, the vehicle will accelerate to a nominal pre-determined speed of approximately 4 km/h before the brakes are pulsed by the brake computer to arrest the descending speed to something more comfortable.

Other makers have had this technology for some time (Land Rover introduced it to the world in the series one Freelander AWD in 1997), but where Isuzu differed, is in making speed adjustments via the foot pedals, rather than the cruise control buttons.

If the set speed was too fast, you simply bring your foot up onto the brake and squeeze the speed down to your preferred lower level, holding the brake for a few seconds before releasing. Travelling too slow now? Rest your foot on the accelerator pedal and push it to where your new higher descending speed threshold might be and again, wait a few seconds, before releasing the accelerator pedal pressure. The vehicle “learns” your speed settings.

Despite being available on South African D-MAXs for the first time, Aussie versions continued to be dumbed-down and missed the off-road-critical, electro-magnetic rear-locking differential.

Leaf Spring Issues

This generation D-MAX also employed a three-leaf pack in the rear springs on LS-U, LS-T and X-Runner variants in an effort to find some more compliance compared to the former five-leaf design.

On release it seemed to live up to the engineers claims, as it rode a lot better, but at a cost, and that was carrying capacity and durability. Most were replaced under a warranty recall with fatigued leaves (broken) or from losing their elliptical tension and sitting flat or inverted, before their owners realised the aftermarket offered way-better and more durable options.

Wheels and Tyres

16 x 7” fitted with 245/70R16 AT – replace with LT245/75R16 120R or LT265/75R16 123R

17x 7” fitted with 255/65R17 HT – replace with LT265/65R17 120R or LT265/70R17 121S

18 x 7” fitted with 255/60R18 HT – replace with LT265/65R18 122Q


After reading all of this you might be thinking the 2012-2020 Isuzu D-MAX was a lemon, but I would disagree.

All vehicles have their strengths and weaknesses, witness Toyota with its DPF and fuel injector woes. Then there are Ford and Mazda with melted pistons in 3.2s from crook injectors and the need to change the oil in under 10 minutes, crook transmissions and mystery CAN-BUS electrical gremlins. Mitsubishi copped plenty with bent chassis on big enough bumps. All of this and more can happen to any make, given enough time and coupled to user ignorance and abuse.

I had no problem investing my hard-earned in our 2014 D-MAX and our 2016 MU-X and you shouldn’t either.

They are a simple, and in our care, reliable truck, even when pushed hard on a daily basis, both on and off-road.

The RT Euro 4 models (2012-2016) stand out as being the less troublesome, unless of course the turbo flaw has been fixed in the RT Euro 5 (2017-2020) unit you are looking at. Fix a couple of other things and you’ll end up with a 4WD that will reward you with some fabulous adventures and the aftermarket looks after the model with plenty of accessories to plug the gaps.

Visit our D-MAX product page

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