Clunk in manual trans drivetrain

[ErikS]

2002 SL, manual trans, 80K miles
Car runs great, shifts/runs great, but experiencing an increasing clunk on alternate accel/decel while in gear, and with a clunk when most often starting out in first gear.
CV joints OK, as verified by local mechanic, who indicated that it was a transmission issue.
On searching this forum, see that other possible causes may be motor mounts or lower control arm bushings, but didn't find anything exactly matching our symptoms.
Suggestions?

[93twincam]

Without hearing it or being able to drive it, sounds like it could be motor mounts. I would check those.

[cgg17]

Perhaps the diff pin is working it's way loose. Pull the VSS (vehicle speed sensor) and check through there to see if the differential pin is dislodged.

When mine blew I heard a metallic "ping" noise a few times throughout the day. The next day it blew a hole through the trans.

If it is a clunk in low gears only, it very well could be motor mounts. When the TAM (torque axis mount) collapses, and the bottom engine dogbone get sloppy, oftentimes the engine will contact the subframe.

I would suggest an inspection of the differential pin through the VSS hole, and if the differential pin checks out, inspect/replace the motor mounts.

[trottida]

When I had that experience it was that the 3 bolts on the timing cover for the upper motor mount that had loosened off. I torqued them down to spec and the problem went away. I've heard of others where the 3 studs in the timing cover sheared off.

[RockHudStone]

I have this problem now. I changed the top motor mount and the dogbones. Wrenched as many nuts and bolts as I could find. shook everything. looked at things with a flash light, don't see what's moving. Thought maybe it had something to do with anti-swaybar mounts but they seem fine.
I suspect the drivers side. when it happens in first in the rain the left wheel slips a little. But don't hear anything on tight left or right turn so don't think it's the CV joint but don't really know. It's gotten almost constant so when I'm sure a mechanic will notice it I may bring it in for service.
Or wait for it to get worse and see if I can find it, dont know.
It's like the wheel move forward or back a small amount with accel/decel or accel after breaking in neutral so its like a slight wheel movment. But sway bar was replaced and ends and mounts are tight. Wait and see.

93 SL2 Manual 195,000 miles

[RockHudStone]

PS- Its a sometimes "clunk" on accel/decel. When it happens in the rain at a stop light on an up hill, at that moment the left wheel skips a little. Other then that there is no pull on the steering wheel so I don't really know if its a wheel movment. I don't know?

[ErikS]

Hey all,
After replacing motor mounts (didn't help), replaced lower control arms and tie rod ends - which took care of the problem. Car runs great again!
Guess the local mechanic did not want to work on my old Saturn......