Afternoon all, I've noticed a bit of a problem with my indy. Theres always a clunk when changing gear (i know this is common with the R1 engine) but it always seems to be coming from the back of the car, it also does it when you back off the throttle and let the car coast along.

To see what was going on (engine off and neutral selected) I grab the propshaft, when I turn the prop the car moves forward, I turn the prop the other way and there is about 5 degrees of free play where it turns very freely without moving the car, then theres a clunk and then the car starts to move the other way. The UJs on the prop seem fine, does this mean my diff is knackered or do they all do this?

Cheers

Paul

[Edited on 16/6/06 by Paul G]

not sure if we both have worn diffs, but mine does it too, gets much worse after a run as the diff oil heats up and thins out.

i thing its just one of those things

I hope it is just one of them things and normal, I want to finally get round to driving my car not fecking around rebuilding it again!

Have you checked if the half shafts/drive shafts dependnig on what you call them rotate with the free play?

Could be worn CV's also.

Chris.

No mate I havent tried checking the driveshafts but would any play in these still not be from the diff? Do you mean the play could be coming from the flexible parts of the driveshafts (are these just universal joints like in the prop?)

Also what are the CV's and how do I check for wear?

Cheers

Paul

CV's are different to a UJ.

One is a constant velocity joint and the other is a universal joint. The main difference is that a constant velocity joint transmits a 'constant velocity' from the inner to the outer shaft independant of angle.

A Universal Joint will transmit a jerky quick slow, quick slow movement that gets worse with an increase in the angle of transmission. This explains it better...

http://en.wikipedia.org/wiki/CV_joint

http://en.wikipedia.org/wiki/Universal_joint

If, when you turn the prop with your hands the play doesn't affect the drive shafts then the play is in the diff. If when you turn the prop the inner shaft moves but the outer doesn't then the wear is in the CV.

HTH,

Chris.

mine clunks as well

all diffs should have some backlash, but obviously as they wear, the backlash will get steadily greater and much more apparent.

just make sure that it is definitely backlash that's making the clunk, as in about 400 miles, my prop bolts had come loose. that was making a hell of a clunk though. a bit of loctite bearing fit stopped them coming loose again

hth
tom

if its any consolation mine also clunks like hell.

I think it is a combination of bike engine and sierra diff.
I think a torque tube or similar would cure it. This takes the intial bite out of the output shaft when engaging gear.
i am sure someone on here as fitted one.

Mine clunks a bit too.

Going to Newark Paul?

I've got more than 5 degrees of backlash and big clunks and also drivetrain noise (chatter) when running at constant speed.

In fact on the way to Stoneleigh It Clunked so much my prop clunked right off at 90.

I have added a TRT rear prop (after reverse box) and this has helped to reduce the noise a bit but I think I'm overdue for a new diff.

Me too, I assumed it was a 'feature' with having bike engine and car diff. Mine also 'rattles' alot when in top gear on the motorway when I'm just tickling the throttle to maintain speed.

Cheers

Rick

Ah cheers for all the replies fellas, glad its not just mine that does it. I'll take another look when I get chance and see if it is the diff or the CV joints.