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Sierra diff clunk once now leaking
matt5964 - 27/6/16 at 08:16 PM

As title says I was at Bedford gt on Saturday and during the last session I got proper sideways on the second part of the Chican just before the stright and ax I ciollected it there was a clunk/bang from the rear I lifted off the power all seemed well so I got back on power and another clunk was heard but half the noise of the first.
Again all felt well so I got on the power gently to get to side of track, there was no noise and it drove well so I decided to continue on as to not cause a red flag. The car drove well no noise at all and pulled well. The only thing was that it felt like the LSD part was not working(if that's possible as when comming out of bends the inside where span up a bit, I thought the. Tyers (toyo R1R) had got over hot and loosing grip.

Back to the pits for a ferrie around and could not find anything wrong, drove the car home and all was OK agains looked and all seemed fine.

Tonight I have a look and the diff is weeping oil from the rear case housing but not loads

Any suggestions?


madteg - 27/6/16 at 08:41 PM

I have had my lsd leaking out of breather pipe on track. Found out it was boiling the oil and blowing oil vapor out, now i feed it to a catch tank 300mm above the top of the diff and check every time i visit a track.( I have not had any oil in tank as yet) I put it down to the lsd plates creating heat on a prolonged period and not designed for the abuse we put them through


Rob Allison - 28/6/16 at 02:10 PM

You could have damaged the planet gears. They are the weak part of the diff. also the cir-clip may have poped of one of the output shafts. Its also possible to split the main case but normally you need twice the power you have to do that.


matt5964 - 28/6/16 at 05:17 PM

Thanks guys.

Think I'm going to get road and race transmission to look at it and rebuild if possible else it's hunt for a new one, but there don't seem to be many 7" bolt on lsd's about