TR6 Clunking in rear

[pdplot]

Pulled wheel today with son's help. Findings:
1. No frame cracks - period.
2. Tube shock bolts tight.
3. Bump stop rubbers in good shape.

Sounds like it might be coming from left side of differential. When you bounce the right side of the car, there is no clunk. Any ideas?

 

[Marvin Gruber]

Car jacked up, wheel off the ground, E brake off, trans in first gear, both hands on wheel that is jacked up, rock/turn wheel forward and back. You might hear same clunk. It could be universal joint.
Marv

 

[pdplot]

Will try, Marv. I'll let you know. These ^%$# TR6 rear ends...a "triumph" of British engineering.

 

[Tybalt]

How closely did you check the differential mount pins? This is known problem child area on these cars and the first obvious symptom is getting a "clunk" in the rear end. It's no unheard of to have the cracks shielded from view by the differential mount bushings. Take a look at what they show here about halfway down the page for an example:

https://tr6.danielsonfamily.org/DiffMounts.htm

 

[mallard]

Dry splines on the half shaft could cause a clunking sound.

 

[trrdster2000]

PDPlot, There are so many things that can go bump in the night on those rears, you may find more than one thing that is giving you grief.
I do agree the mounts are a big issue for cracking on the right side at the top, there is just enough space you can get a hand between the body and the frame to feel in there or take the wheel off and use a mirror and a flash light, the bolt goes through the frame and is welded all around, it will be easy to spot a problem.

Wayne

 

[poolboy]

I had a cracked right front mount, but it did not create a "clunk" sound. If I had to describe it, it sounded like the noise an aluminum drink can makes when it's bent in half...a crisp metallic sound...not a dull clunk.
What did make a clunk was an inner metal sleeve in the rear differential mount that had broken loose of it's bond with the surrounding rubber portion of the mount. It clunked pretty regularly during gear changes and at the beginning of sudden acceleration or braking.

 

[trrdster2000]

OK Poolboy, I was with you until the "sudden acceleration", then I had to see which forum I was on, thought I was on the Jag one. LOL

The rear of the TR6 has many clunks, very difficult to find sometimes.
Wayne

 

[poolboy]

You thought I meant "rapid acceleration" ?

 

[trrdster2000]

Taking a little mickey out, as my English wife would say. At certain speeds the 6 will surprise in a AutoX, still love them and mine is a joy anytime.

Wayne

 

[poolboy]

Yeah you right... get the gear and the rpms matched up and it's pretty "torquey".

 

[pdplot]

Jacked up car and rotated wheel/tire while in first gear as suggested by Marv. I had exactly one inch of free play in the left half shaft. At each end of play, it did make a noise but not the one I'm speaking of - just the normal noise when at the end of travel of free play.Did not compare the right side since the car would have to come out of the garage and it was raining. My clunk occurs on the upstroke when you push down on the left rear bumper and every time when hitting a bump in the road when under way. it's quite loud and sharp sounding.

 

[Got_All_4]

Trailing arm loose? That was my first clunk. Rear diff-mounts was my second, fixed that then another one showed up and that was the UV joints. Good for a few weeks and now there is another clunk. It's been several years since the diff mounts went so I'll check them. Thanks for the reminder.

 

[pdplot]

Supposed to have the rear looked at by a fellow TR6 owner this am but it was pouring and my car has never been out in the rain since I bought it over 20 years ago, s-o-o the inspection will be put off again. In the meantime, the sun came out and so did the TR6 and I'm down here at the office getting ready for the City to take my building for a new police station. We close on July 2nd and I have to be out on that date. I just finished going through 53 years of files, one by one and now over 80 plastic bags are ready for the shredder on Tuesday. Anyone want to buy some office furniture cheap? Real cheap.

 

[pdplot]

OK - new theory on clunking noise. It apparently started when I installed the 2" Goodparts spacer to level the rear of the car. I now believe the shock piston is hitting the end of the shock tube on the return stroke because the bump stops are not doing their job due to the lowering of the spring. If this is so, sooner or later the shock mount or the frame will break. I should be able to see if this is so by jacking up the trailing arm with the shock attached. If the entire car raises up before the bump stops hit, thus limiting travel, that will prove my point. Am I on the right track or is this just a cockeyed theory from a shadetree mechanic of a certain age? Will it make any difference if I reverse the shocks from top to bottom?