clunk when shifting

#1

Hello - thought I’d get the collective wisdom. I finally took the car out to the track a few weeks ago, ran a HPDE weekend at Gingerman. Overall the car ran really well. As the subject states, I had a really annoying clunk when shifting reasonably quick - the only way i could get it to subside was to double clutch. I’m pretty sure the reason that worked was the added time it takes and not something internal to the tranny. The car was still running stock engine and tranny mounts - which will be replaced before going to Putnam next weekend. Any other places you’d look? All of the suspension and subframe bushings, strut mounts, etc are all new.

The other things I found was a fluid leaking from the clutch slave and a clicking that increased in frequency with speed. I remember thinking the diff’s input bearing sounded awful when I had it out, so I’ve somehow convinced myself that the clicking is the diff. I’ll have it on the lift this weekend so I should be able to confirm/disprove that theory.

Any ideas on the shifting clunk or the clicking?

Thanks,
Gareth

#2

Does it happen between every gear change? Is the sound coming from the trans area or farther back? How old is the center support bearing and driveshaft?

#3

Almost all of my gear changes were from 3 to 4 - but I first noticed it going out on track from 2 to 3. So at least on those gear changes, yes. The driveshaft is probably original to the car. I didn’t feel any play in the u joints though. Center support bearing is of unknown age but looked ok. Guibo is new.

I’d say the sound was from the trans tunnel, but its hard to say. As soon as I read support bearing though… sounds like a good place to look.

Gareth

#4

do you still have the balancer around the guibo? it could be hitting the shift rod especially if you’ve recently installed a short shifter.
bruce

#5

I removed the balancer.

Thanks,
Gareth

#6

I get a little clunk once in a while from a hard 2-3 shift. I suspect it is my rear end mount/bushing. I have one, just have not replaced it yet.

#7

I had the car out this weekend at Putnam with the new poly engine and trans mounts - the clunk is gone!

The down side was the hard line that goes from the right side of my steering rack sprung a leak. I ended up removing the power steering and patching that line with fuel hose. It got me through the weekend and now I have the winter to fix it. I was amazed, on track I didn’t miss the power steering at all - only when parking did I really notice it.

Gareth