Advise needed: Clunking noise at the rear when taking off - What can this be?

Hi guys. I am looking for some advice.

When i accelerate from stand still i (often) get a "tok" noise from the rear of my Def90/98. Sounds like one metal part hits another one. When the car is cold, it does not happen or it is very difficult to reproduce. After about 10 minutes driving, it starts happening when i take off.

There is no noise when changing gears, neither up or down. Also not when I get off the throttle to "provoke" load change on the system. it is only when i start off.

First i thought it was a worn UJ in the rear prop shaft (had also quite strong vibrations starting at around 40mph). Prop shaft is sorted now, vibrations gone, "tok" noise still there.

Running out of ideas, but here options that fellow LR owners came up with plus my thinking:

- Differential: possible. bearing, pinion etc.
- A-Frame ball joint: Would this depend on the "temperature" of the system? Would say no. Would be there all the time.
- Bushes: Sames as ball joint ?
- Transfer box: Latest theory (expensive one). But I would hear the noise not at the very back, more likely to hear it more or less under the seat?
- Drive shaft / drviving member: worn splines

Any ideas from you side?

thanks
Dietmar

Bear in mind that the noise will be bouncing off the road surface and off of the panels underneath the vehicle so while it may sound as if its coming from the back it could actually be underneath you. Eliminate all possible sources at the rear e.g. diff, bushes, a frame balljoint, half shafts, bearings, wheels etc... Then start working forward

I would hazard a guess at the transfer box splines as when its hot the oil would be thinner so more likely to hear the noise , mate had a similar one which was the rear diff crownwheel bolts loose

Thanks for you ideas. re bouncing sound: possible. I think i will take the center panel off so that i have the transfer box directly next to me and give it a try to reproduce it.

Just take the PTO cover off and check your gearbox splines.

At least if all ok you can rule that out!

harry2012 said:

Just take the PTO cover off and check your gearbox splines.

At least if all ok you can rule that out!

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Yep I would say this also
there is a great write up on here telling you how to fit oil feed plate etc

Take it for a spin and warm it up until you get the noise.

Lie underneath it and get someone else to drive off, see if you can pinpoint the origin.

Could be something as simple as a brake caliper bolt loose, or the exhaust.

A mate had the same and it was rear A frame bearing?

Mine does the same but never changed it to be honest.

Pumpy said:

Take it for a spin and warm it up until you get the noise.

Lie underneath it and get someone else to drive off, see if you can pinpoint the origin.

Could be something as simple as a brake caliper bolt loose, or the exhaust.

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:lol: pls youtube it

Went to a LR dealer garage and the mechanic listened to the noise. He guesses that the half shaft splines might be the issue. So i will start there and exchange them.
Thanks for your input.

A frame ball joint. Does your Defender actually fly as well?

Scrawf

after picking up my td5 I also had this problem , it had the late type halfshafts with the separate drive member on the end, these had gone ####ed and caused a similar noise just with no difference hot or cold , I would recommend changing to the one piece halfshaft like I have done ( RR classic for 10 spline and 300tdi defender for 24 )

Another vote for halfshafts and drive flanges from me. Changing these took out most of my clunk, and the remainder of the clunk was removed when I changed the suspension bushes and the ball joint. It's very smooth now. it can be a combination of a tiny bit of slack in a number of things.

Just to show how much slack there can be in a halfshaft when you think nothings wrong. I just fitted a new front diff, absolutely no play in it whatsoever and it moved nice and smooth. As soon as I put it in and slid the halfshafts back in the amount of play was phenomenal even though the splines didn't look all that bad. Definitely buying new halfshafts and CV joints when I've got spare cash. It hasn't produced a noticeable clunk as of yet but its not doing it much good anyway

the_wolf said:

Just to show how much slack there can be in a halfshaft when you think nothings wrong. I just fitted a new front diff, absolutely no play in it whatsoever and it moved nice and smooth. As soon as I put it in and slid the halfshafts back in the amount of play was phenomenal even though the splines didn't look all that bad. Definitely buying new halfshafts and CV joints when I've got spare cash. It hasn't produced a noticeable clunk as of yet but its not doing it much good anyway

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when I changed the rear halfshafts on the TD5 id removed the old ones and in your hand they had about 4mm play in them ! im surprised they had not stripped yet, after changing to the def 300tdi ones all my play has gone and now I have no backlash at all , on and off the throttle you cant make backlash happen which is odd considering it was a farmers tow vehicle ! will be quite sad to change this transfer box as its better than the recon one I had before ( fitting disco 1 )

I think I have a similar problem with my 1998 P38. Getting loud clunks from the rear when accelerating hard from slow speed, or towing Heavy stuff up hill. Could this be half shafts or diff?

Drive Members are dirt cheap (if pattern parts) and so my first point of attack. Easy to swap (15 minutes max per side) and often an "instant" fix. I carry 2 of them as spares since the B*itpart ones are made of plasticene and fail quite quickly. My reasoning is that I know just where to go to fix the clunk and it saves the failure point being transferred somewhere more complicated and expensive. In other words, the DMs are sacrificial parts.

Steve RW said:

I think I have a similar problem with my 1998 P38. Getting loud clunks from the rear when accelerating hard from slow speed, or towing Heavy stuff up hill. Could this be half shafts or diff?

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You may be better off posting this in range rover section rather than asking a question on a thread that is based on the Fender.

Cheers