• Hey Guest!
    British Car Forum has been supporting enthusiasts for over 25 years by providing a great place to share our love for British cars. You can support our efforts by upgrading your membership for less than the dues of most car clubs. There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Upgraded members don't see this banner, nor will you see the Google ads that appear on the site.)
Tips
Tips

Driveline Clunk Diagnosis

Share this page

I am 90% sure it's the axles, which can be expensive to fix. I had previously replaced the bushings and the U joints, the shocks are tight and the end links were replaced.

Ian
Following your quest to simply know what's causing the clunk been dealing with issue for several years, only happens from dead stop disengaging clutch 1st gear take off, sometimes when exit fwy stop/clutch/shift/clunk, no hard takeoff simply routine shifting/driving. Same Mechanic since '83 inspected, pulled/pried looked/felt for anything loose to no avail as problems is of course intermittant and has yet to clunk during his test drive when at his shop the latest being 8/2011.

Clunk appears to be torque related during inital take off, sounds/feels like something hangs up then snaps loose, told him guess I'll have to wait until whatever it is finally breaks for me to know. Have rear shock conversion with short angle from top of shock tower to body for added support. Thinking diff & mounts were bad replaced diff 2008 with poly bushings mounts (clunk was there prior with rubber mounts) 2010 replaced drive line with R. Goodparts heavy duty driveline with larger u-joints, GPs adjustable trailing arm brackets, panasports on 205/70/15s

To date the problem still exists, when I think it might happen nothing, then out of no where clunk! like you gut feeling it's the axles which are on my bucket list and the only thing not replaced from tranny to rear and they definitley have high miles on them. Aggravating as it is best wishes in your search for the cause.

Julius
 
Poorly lubricated or worn half-shaft splines might do that. The torque keeps them from sliding, and in a quick take-off the rear wants to squat, but can't until the torque eases on the splines and they can slide.
 
TR4A_IRS said:
I was able to detect play in both axles by holding the axle at the differential flange and rotating the corresponding wheel. I am just not sure how much, if any, play is normal.
Click to expand...

I've had the half-shafts off my car before and it is my recollection that on at least one I could feel a fair amount of rotational slack in the splined sliding joint. And going from memory again it seems to be I looked it up and they were available new in the range of $300-400 a side. Based on a careful cost-benefit analysis I elected to only replace the failed u-joint and put the rest of it back together. There's a little bit of slack in the diff as well and together they add up to a fair bit of shunt. Having taken the spline joint apart and looked at it I can well imagine that a new one would feel tight, seems to me one side was better on my car as I mentioned. I did replace a noisy hub bearing which showed no play or signs of getting worse, just detracted from my enjoyment of the car enough to seem worth it. I.e. those types of decisions- to replace the 'serviceable but could be better' - are down to your own choice and I wouldn't presume to advise on that. From what I have seen, significant wear on the splined joints is possible and this could be at least part of what you can feel as you surmise.

Pete
 
I have a pair of half shafts complete with the outer bearings that are in good shape, I replaced mine with goodparts CV axles, I will let them go if you need them I also have a rebuild diff unit, I put in the Nissan R200 unit last week end

Hondo
 
After 16 years of looking for and never finding it in my TR6, I gave up. Did just about everything mentioned including axle half shafts. It was exactly as described. Clunk somewhere in the back when just taking off. It must be pretty common.
 
I don't mean to highjack the thread but I also have a clunk in the rear. I just replaced diffrentle bushing and shock links. I had replaced all of the u-joints before I rebuilt the engine. The lever shocks seem to be tight.

My clunk seems to be when I go over a bump. I am pretty sure it isn't the tailpipe. I am thinking that it might be trailing arm bushings. I will change them next.
 
I'm with you looking for the clunk in my 4A. I just wrapped my emergency hand brake cables in foam as George suggested, and I'll soon be on the road to see if that's the fix. If not, it's a mystery. I've checked about everything.
 
But on those half-shafts, no question about it. On take-off, they will knock a bit. Mine was slight, but it bothered me. I now have CV axles.
 
Sounds like to me your differential is the source. if everything else is right, then I bet your differential is the problem. I replaced my half shaft with CV axles mainly because of them locking up on take off and I didnt like that side ways jerk when they let go, but still had a clunk, usually noticed it when just starting off in first gear and going over speed bumps, went thru the same things, all u joints, tightened up the shock mounts replace differential bushings, Thats Why I got a nissan R200 differential, and now no more noise from the rear end. Any yes I even purchased a rebuilt differential from the guy in Conn, it seemed to be less noisy but still clunking, if you prefer to stick with the original equipment I have the rebuilt unit I took out, but I have read even when they are rebuilt they still clunk some.

Hondo
 
Back
Top