Possible brake or transmission problems

The new ute
DmaxNZ
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Joined: April 27th, 2015, 3:28 pm

Possible brake or transmission problems

Unread post by DmaxNZ » April 27th, 2015, 4:25 pm

We have a 2014 Dmax LS 4x4 auto, it's just had its 10km service. The problem is that when the vehicle is in drive and the foot brake is depressed, as at traffic lights etc, as I lift my foot off the brake pedal to then apply the accelerator the sensation is that the gearbox engages its first gear and a "thud" is felt through the brake pedal. At first I thought it was the brakes sticking somehow, but my dealer had the vehicle for 2 days and said they stripped the brakes and found no fault.
The "thud" doesn't happen every time but enough to make me think that something is not right, a passenger in the vehicle also has felt the "thud". I previously owned a 2010 Dmax which was inferior to this later model but braking and accelerating in traffic was very smooth.
I approached another dealer who advised that the issue might be around the hill start assist, but he then advised me that my model doesn't have this feature. I am still waiting for a response from my dealer as to their next step as I pointed out the problem to them again.
I have been driving for 30 plus years and have driven many automatics, utes and other 4x4's and never experienced this issue before. Or this the norm for a 4x4 auto ute.
Has any other Dmax owner had this issue?

LST Newie
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Re: Possible brake or transmission problems

Unread post by LST Newie » April 29th, 2015, 12:18 pm

Other owners have experienced similiar to what you are describing but with varying degrees of harshness. It seems to be a trait, albeit an annoying one, of this model. IMO it has something to do with the drivetrain, as in the yoke into the trans. When you drive on cruise and cancel it with the button there is no clunk but if you cancel with the brake pedal you think WTF was that!
Guys who have had a 2" lift done have had to get there tailshaft extended or a spacer made because this slight lift means the yoke is not seated far enough onto the spline of the output shaft.
I think your problem is there. Depends how hard you come to a stop which determines how much wind up is in the rear suspension/axle and pulls the yoke rearwards

Only solution to prove what I suspect is to mount a camera under there to record what is going on

FJRider
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Re: Possible brake or transmission problems

Unread post by FJRider » April 29th, 2015, 12:52 pm

I have a late 2014 SX Auto , I have a ARB GVM upgrade , so it has quite a lot of lift in the back , can't say the same for the front it is now sitting a Std hight . I haven't noticed any thing like what you have ,
Anyway that's not really why I replied to this thread , I just wanted to say my SX has the hill start feature , I would be surprised if your LS didn't , still may have nothing to do with what you report

What LST says makes sence .

Lord_Muck
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Re: Possible brake or transmission problems

Unread post by Lord_Muck » May 4th, 2015, 3:07 pm

I had the exact same issue, especially stationary on a slight decline, then every time i let go of the brake it would do it, pointed it out to them for my 3000km tyre kick, they told me "mmmmm it's the brake calipers moving, it'll go away". I highly doubt their assessment of it, however it did go away coz it did it from 0-5000kms or so and i haven't noticed it since.

DmaxNZ
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Re: Possible brake or transmission problems

Unread post by DmaxNZ » May 23rd, 2015, 9:32 am

Hi All
Sorry for the late reply, been working away, drove the vehicle this morning for the first time in a couple of weeks. The problem is getting worse, it's now done just over 10,000 kms. I'm going to contact Isuzu head office to see if they can offer any help. I will mention LST's comments and see what they say.

Thanks for your responses.

LST Newie
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Re: Possible brake or transmission problems

Unread post by LST Newie » May 23rd, 2015, 7:39 pm

I have read that a solution to the problem is to pack the yoke with grease and this was also the case for another brand with the same problem.
However, the grease dissipates and the problem comes back. It could be a case of the engine/transmission is sitting too far forward on its mounts and needs levering rearwards a bit after loosening the engine mount/transmission mount bolts to reduce the distance between the back of the trans and the diff flange. This would be my first tack at fixing this symptom

mydmax
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Re: Possible brake or transmission problems

Unread post by mydmax » May 23rd, 2015, 10:14 pm

Packing the yoke with grease only adds grease to the transfer case lubricant.

jazzeddie1234
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Re: Possible brake or transmission problems

Unread post by jazzeddie1234 » June 9th, 2016, 10:19 pm

My Dmax has started doing this (20,000kms) quite often and driving me mad. A lot of googling and I found a few things of interest. Someone was able to film the drive shaft and the slip yoke slides out a little under braking but does not smoothly return until it rolls forward - hence the thump feeling. Other 4wds in the US have similar issues and Ford even published a service bulletin - which I will try and report back.

In short you drop the drive shaft, lubricate the slip area with oil (ford said to use atf but I assume this was to do with their gearbox running atf) and reinstall. They specifically say not to use grease but again this could be because they are concerned with atf close tolerance gearboxes.

Very disappointing as I spent months diagnosing a vibration on my 2009 lifted dmax which came down to a loose tolerance slip joint - which solved the issue once replaced. BTW that replacement removed almost all free play in the driveshaft compared to my new dmax which has plenty
Isuzu Dmax 2014 LSM,
Sports Range bull bar,
12,000lb winch, ome suspension, 135l poly long range tank

jazzeddie1234
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Re: Possible brake or transmission problems

Unread post by jazzeddie1234 » July 14th, 2016, 10:27 pm

So I drained the transfer case and replaced the oil with synthetic 5w-30 which is the closest to the one specified in the book. I may be dreaming but I think the problem has greatly reduced and only occurs when braking hard enough (to a full stop) so the rear lifts slightly and then squats back to normal - at that point I still feel a thud. But it is well within what I am happy with.

This suggests the thinner oil allows the yoke an easier slide?

My max is back in the dealer tomorrow to replace another transmission oil seal... :mad:
Isuzu Dmax 2014 LSM,
Sports Range bull bar,
12,000lb winch, ome suspension, 135l poly long range tank

jazzeddie1234
Been here a while
Posts: 209
Joined: December 10th, 2010, 12:02 am

Re: Possible brake or transmission problems

Unread post by jazzeddie1234 » April 9th, 2017, 10:11 pm

Another update...
The transmission thump was ok for quite a while but returned - I was 5 months towing with 250kgs on the ball (2.7t caravan) so my braking technique was much more moderated and the suspension more compressed which may have put the height closer to stock. I have now fitted a 15mm tail shaft spacer from iron man (much cheaper than superior E) and this made an improvement when unladen. The thump now feels more like a transmission change down on a (hard braking) stop and the slip joint side play is greatly reduced.
I was ok with 15mm spacing but be careful to check there is some slip left on full compression!
Isuzu Dmax 2014 LSM,
Sports Range bull bar,
12,000lb winch, ome suspension, 135l poly long range tank

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