Dmax body mount failures, and how we replaced them

We’ve had our Isuzu Dmax now for about 6 years, and overall its been fantastic. We’ve had a couple of smaller issues, which we’ve written about. If you are looking for the more common problems that occur with the MUX and Dmax varieties, you can read about it here – Isuzu Dmax Problems.

If you want to read everything we’ve written about our Dmax, including fuel economy figures, what it cost to build, what it weighs and heaps more, you can check it out here – Isuzu Dmax.

In the earlier post, we mentioned how the inner guards can crack, and that its an extremely expensive and difficult repair to get done properly. Thankfully, we haven’t seen this, but it has made me keep a much closer eye on the body mounts on our Dmax.

EDIT – at 90,000km, I noticed the first inner guard cracking, and have been monitoring it since (and it got way worse). This eventually failed in a big way, and we had our Dmax inner guards replaced under warranty at about 112,000km.

EDIT 2 – We’re now onto our second set of replacement body mounts, as they were looking awfully sad.

Dmax body mounts
Body mounts are pretty important; how often do you check yours?

What is a body mount?

Your 4WD runs a number of rubber assemblies in between the chassis of your 4WD, and the body. It reduces the noise, vibration and discomfort being passed through to the body which is far more susceptible to damage. These are essentially an isolation mount, and they isolate the two items. 

If you’ve ever seen slow motion footage of a 4WD off road on corrugations, you’d see that the bull bar seems to move a huge amount. In actual fact, its the body moving on the body mounts, and the bull bar is not really twisting at all as its attached to the chassis.

Body mounts are hugely important, and if they are damaged or incorrectly installed you can end up with knocks, cracking noises and stresses applied to your panels that they were never designed to have.

Dmax body mount failures

Upon my latest inspection, I saw the front left body mount had some damage in one section, and the front right looked even worse, with disfiguration in two places, and a crack starting to appear. With a service booked in anyway, I sent an email to my local Isuzu to have the spares ordered and ready.

I was not taking any chances, as leaving them would result in a much greater chance of cracked inner guards. At $341 plus labour for a set of new body mounts, its a no brainer. 

Still, at literally 65,000km on the clock its a premature failure, and average at best, and I was going to fight hard to get it done under warranty.

Body mounts replaced
The body mounts replaced on our Dmax with obvious evidence of cracking and failure

Isuzu Warranty

Our Dmax also had a rear differential pinion seal replaced, which the warranty was approved on extremely quickly during the service. I was actually surprised, as I expected that they’d decline it on the basis of aftermarket suspension, and the tail shaft spacer.

However, the dealer didn’t get a response from Isuzu head office in regards to the warranty claim for a number of days, and when I went to pick the vehicle up they suggested I should pay for it.

I said no, wait until Isuzu get back to you and if they don’t cover it I will. At $900 including the labour, I could have paid for it, but felt that I shouldn’t have to.

Eventually, they did come back and it was fully covered by Isuzu, and now I have the damaged body mounts in my garage as a reminder.

Dmax body mounts
The parts replaced, sitting in our garage

Swap them to Colorado body mounts

A lot of people are ditching the Isuzu body mounts and replacing them with Colorado ones. For those who don’t know, they are essentially the same vehicle in many ways, but the body mounts are different.

The Colorado ones are bigger, and stiffer, and those who’ve changed them say there’s far less movement and they behave well.

I am loathe to do this, because they are not what Isuzu supplied and having already dealt with their warranty department a number of times they would decline any guard cracking 100% if they knew you’d run different body mounts.

Sure, the idea of installing the Colorado ones to stop the cracking might be valid, but is it worth the risk?

The cracked panels is a massive job to do properly (6 – 10k worth) and its not something I want to mess with.

Does this cause the inner guard cracking?

The inner guard failures are relatively common, and I’ve seen them happen on vehicles punished off road and barely used off road, as well as vehicles with bull bars and without bull bars.

The exact cause remains to be seen, but having soft, or damaged body mounts would certainly contribute to the likelihood of failure.

I was told that there was an error with the type of steel used for the inner guards which is brittle, and this is probably also quite likely.

I was also told that the service technicians have been asked to inspect body mounts on each vehicle coming through, because they are failing prematurely and Isuzu are having plenty of cracked inner guards.

I have also seen a number of people with Ironman snorkels that have had cracking, which has been traced back to the removal of critical bits of material which weakened the whole inner guard.

If you have cracked inner guards, you can register your interest with Bannister Law, who are now looking into the cracked inner guards and DPF failures (or mainly turbo issues).

They’re on the way out again

After noticing the crack in our inner guard, I took a good look at the body mounts, and after just 30,000km the front left side has cracks, and is starting to deform, although its pretty mild.

Its pretty clear that these are not as durable as they need to be, and they contribute to issues on the front end of the Dmax.

Check your body mounts

If you have a Dmax or MUX, I’d seriously advise you take 5 minutes to check your body mounts, particularly the ones around the front of the vehicle.

Check the inner guards for cracking too, and if there is any damage I’d suggest you consider taking it back to Isuzu to be looked at.

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  1. Hey Vic,

    Funny you mention it; I had my head under there the other day having a look, and they seem OK. The vehicle is covered in mud at the moment though, so I’ll have a better look when its nice and clean.

    I expect we’ll get another 50k without too many issues, and hopefully longer. If they go again I’ll be fighting Isuzu for a poorly constructed component, or design.

    All the best

  2. Hi Aaron,
    How have the replacement genuine Isuzu body mounts held up? Still good after how many km? Love your articles…many thanks!

  3. Cheers Bryan,

    Hopefully something not too serious is picked up!

    Take care

  4. Bryan Dalby says:

    Hi,Aaron ,
    Took it to the Isuzu dealership but after a quick look they could not find any faults.Not being satisfied I have booked it in for a thorough checkover.Will let you know the outcome.
    Regards Bryan

  5. Hey Bryan,

    Sorry to hear that. Sounds interesting; is this from sagged/cracked body mounts? Have you inspected the engine bay for cracks?

    Take care

  6. Bryan Dalby says:

    Hi Aaron,
    my 2015 MUX as started vibrating on the passenger side, below the front window in the engine bay.It is an intermittent problem and happens usually when the engine is idling I have never been off-road and its only travelled 23,000km.
    Regards Bryan.

  7. Hi Neil,

    If it doesn’t have manual hubs (as in you can’t see them on the inside of the front wheels), then they are automatic connect/disconnect, but its done internally. They come from the factory like this, and a lot of people install manual locking hubs as an alternative

    All the best

  8. Neil de Coite says:

    Hi Aaron,
    I have a 2014 Dmax, second hand, and am so far pretty happy with it. However I am trying to find out if it has automatic freewheeling hubs and cannot find out. I have the manual that comes with the car and can see nothing about them in that and also a workshop manual in which again I can see no mention of hubs. It certainly doesn’t have manual ones.
    Any ideas?

  9. Hi John,

    Sorry to hear you’ve been having issues. I have the old mounts here, but no pitch gauge and wouldn’t be able to give you the exact pitch. That said, it is M10 and appears to be normal pitch.

    If you take a nut to a bolt store they’ll be able to clarify for you.

    All the best

  10. John Barton says:

    Hi. Have also had issues with my 2013 D Max cabin to chassis mounts. On my vehicle the front left mount bolt has broken. Essentially the the threaded section of the bolt has broken off in the threaded boss that is part of the cabin. I will need to drill out the broken section of bolt. Are you able to tell me the pitch of the bolt thread that is in the left hand front mount.