Jon Hanson

When I am accelerating, if I let off the gas, I get a very noticable "thump" sound coming from the transaxle area. Also, I have to baby the clutch to keep it from thumping when I shift. Anybody know what is causing this? Is this the famous rubber clutch center, but wouldn't that create a thump sound forward of the shifter?

Luke

your tranny mount is weak rubber. replace it or fill it up with coak.

if you are moving slowly, then step into the throttle harder, does it do the same thing?

Check out the post "ut oh....big bucks!?" by lemon yellow, currently two pages back. [quote]Originally posted by Lukesilver95186:
<strong>You need a trans mount right. It is a Metal shell the has A hard rubber on the inside. The rubber stiffens the area around the metal hook the bolts to/ and / suspends the tranny. If you fill the mount (around the rubber) with that hardening coak. it would be like having a new and "slightly" stiffer tranny mount.

Unless you are referring to problems that you are having with the transaxle cross member.





This is a koelin solid trans mount ($170). The oe items are cheaper. Notice this one doesn't have the metal shell around it, because the post is not encased in rubber.

When tranny mounts start going bad, you can feel a back and forth motion to the rmp's are you accecated from a stop. This is because the rubber is old and cracking, and the tranny is actually moving.</strong><hr></blockquote>

TomH

Hey, I have a similar situation with my automatic and thought it was the tranny. When I come to stop lights and the auto downshifts to first, I feel a thump. When I accelerate from a stop there is a similar but not as heavy thumb shifting into second. Could this be my tranny mount as well?

Car runs great otherwise, including smooth shifting into third and running at high RPM/speed.

Skip

Jon: It absolutely would cause a thump sound just forward of the shifter... that's where the clutch is.

Quick check on the rubber center failure:

- lift rear of car safely
- out of gear, clutch engaged
- reach into hole in front of tranny (trapezoidal rubber piece must be removed)
- attempt to turn the shaft

If it turns more than just a degree or two, your clutch center is failed/failing. That sound you hear is the metal cogs on the clutch disc banging together. Commonly, the failure mode is described as lurching, especially on deceleration.

Good Luck!

Jon Hanson

Thanks, guys, I'm now 99% sure it's the transaxle mounts. Anybody have reccomendations on where to pick up these? I don't race my 944, so if I get non racing mounts, it's not a prob. TIA

*EDIT* Pardon my ignorance, but what is coak.?

*EDIT* Picked up a couple tranny mounts from <a href="http://www.partsheaven.com/" target="_blank">Parts Heaven</a> for $25/ea.