Transmission Question

[Mblinko]

Over the last few thousand miles I have noticed a small clunk from what seems to be either the transfer box or rear axle. It is not alarming at all but I have noticed it only clunks when pulling away from stationary AND turning either left or right, e.g. from junctions. It does not happen when pulling away from stationary AND going straight ahead.

If I had to guess, I'd say the clunk was the one or other of the rear wheels catching up after having to turn on a different radius when going round the corner, suggesting either rear diff or half shafts. Transfer box is not silent but then again it is not noisy. Truck has done 204k now and otherwise is in good order.

Anyone any ideas or experience of this sort of thing?

 

[StarCruiser]

The truck isn't fitted with an automatic type of locker in the rear diff is it? Can't remember the type but some of them click - or clunk.

The only clicks I've had doing such manoeuvres are from the CVs but of course these clicks come from the front.

Could it be a worn bush on your anti roll bar or the like? Drop link perhaps?

 

[Mblinko]

The truck isn't fitted with an automatic type of locker in the rear diff is it? Can't remember the type but some of them click - or clunk.

The only clicks I've had doing such manoeuvres are from the CVs but of course these clicks come from the front.

Could it be a worn bush on your anti roll bar or the like? Drop link perhaps?

It's a regular diff with locker, not LSD. All the bushes are new everywhere. Definitely not the CVs though.

 

[StarCruiser]

Any play in the driveline beyond normal? UJs perhaps?

 

[Mblinko]

UJs are new this year.

 

[StarCruiser]

I'm out of ideas MB. Hope you find it and it's not too expensive. Good luck with it.

 

[Mblinko]

Cheers for the thoughts I'm still erring towards diff or shafts but need to wait for more experience to pass by this thread.

 

[frank rabbets]

The centre diff isn't stuck on is it. Probably not as you would notice other symptoms.

UJ's are new but that is an area where recent work has been carried out so worth checking.

 

[AndyCook]

Genuine Toyota UJ or cheaper millers/roughtrax ones ?

 

[clivehorridge]

I would suggest UJs or wheel bearings, as both can cause a clunk sound, but the "turning" component of your post would point toward the rear differential (as you've ruled out the sound coming from the front).

Sounds do transfer through the drivetrain so I wouldn't be surprised if it was a fault forward of the rear axle.

 

[Mblinko]

The centre diff isn't stuck on is it. Probably not as you would notice other symptoms.

UJ's are new but that is an area where recent work has been carried out so worth checking.

No, it's not on. Good point to check and see if anything is loose though.

 

[Mblinko]

Genuine Toyota UJ or cheaper millers/roughtrax ones ?

Toyo ones, but I can't remember who sold them to me.

 

[Mblinko]

I would suggest UJs or wheel bearings, as both can cause a clunk sound, but the "turning" component of your post would point toward the rear differential (as you've ruled out the sound coming from the front).

Sounds do transfer through the drivetrain so I wouldn't be surprised if it was a fault forward of the rear axle.

Wheel bearings are about 30k old now. Again they were Toyo, but I've no idea what life I should expect from them.

Sometimes it feels like it's under my seat hence thinking perhaps it may be the transfer box, but I don't understand why it clunks only on corners.

 

[t1pper]

Rear propshaft UJ allignment, they must work as a pair.
Not sure if the splines can be assembled incorrectly??

 

[Mblinko]

Yes they can be assembled wrong. It's prop phasing. I was careful to ensure it was right though as it causes vibrations and wear.

 

[t1pper]

Maybe worth dropping the oil on the front diff, rear diff and transfer box it is cheap and a quick job.
Examine the oil if one has a problem it should be evident by metalic debris or particals in the oil.
If there is nothing to report then it would strongly suggest toward the problem being else where in the drive train.

 

[frank rabbets]

Yes normally any problem inside the axles or boxes would almost defo cause metal particles. No up/down play in the axles or boxes flanges?

Perhaps an assistant could drive and replicate the noise with you walking around beside the car.

 

[Jon Wildsmith]

You said all new bushes everywhere - did the clunk happen before you replaced all the bushes?

 

[Mblinko]

You said all new bushes everywhere - did the clunk happen before you replaced all the bushes?

TBH I can't recall so I'm going to have to eliminate them.

 

[AndyCook]

Are the toyo UJ's the £10 ones ?
Check them for play anyway