'96 SL1 Transmission Clunk When Shifting

Update: I removed the torque axis mount and it looked like the rubber had shrunk pretty badly so I went to the local dealer and bought a replacement ($73). it seemed much stiffer, so I was hopeful that it would resolve the clunking.

Unfortunately, the replacement made little difference, although the engine does not move as much anymore. But, the loud "clunk" when shifting is still there and sounds like it is getting worse. The clunk is heard worst when shifting between park and reverse, and then less noticeable, but still bad between neutral and drive. I did not hear much going from drive to 3rd and then 2nd, although there seemed to be a faint "buzzing" in 2nd while still at a stop. When I take it out of the garage for a spin, the clunk is bad on every shift and downshift too, but they appear to happen at the right RPM/speed. When it is in a single gear, like 2nd, it drives perfectly and sounds fine. It is only when it up and down shifts that it sounds like it is getting torn apart and the shift is extremely harsh. .

Can someone who has had the auto trans "valve body" problem please describe the symptoms and approximate cost of the part & difficulty of the repair? Any other ideas? Thanks in advance.

Bob

Have you tried a drain and fill (or two) of the trans fluid? I started having the signs of the valve-body problem (slippage, clunk/hard shift), but a drain-and-fill with Mobil Synthetic Trans Fluid fixed the problem for going on 8k miles.

After I replaced the Torque Axis Mount and saw no improvement I drained the fluid and changed the filter hoping that would solve it, but again, no improvement. (The previous fluid and filter had been replaced just about 18 months and 15K miles ago.) As a last resort, I even tried removing the battery cable for 2 minutes to reset the transmission computer. Again, no improvement.

At this point I'm researching a Saturn Fans web site that has an unorthodox "cure" for the "reverse slam" posted. It involves running the vehicle in reverse against a stationary object for 30 minutes to get the fluid hot and force it through the clogged valve body. I figure there isn't too much to lose at this point, but would like to verify that my symptoms are in fact caused by the same fault since nowhere did anyone on that site mention clunking when shifting forward gears.

Thanks for the thought. If anyone else can confirm this is the reverse slam or provide other thoughts, let me know.

Bob

Thanks for the reply. It engages perfectly and seems to be at the normal time when shifting from park to reverse. There is no noticeable delay. It also shifts at normal times when driving or so it appears. The only symptom is the extremely harsh nature and loud "clunk" that comes with the shift, even when at a dead stop and engaging the gears for the first time when attempting to back out of the garage.

Any other thoughts? My intention is to try to 30 minute reverse at idle with the brakes holding the vehicle still. At this point I've already changed the fluid and filter so all I need to do is add the trans cleaner additive. So if it does not work, I will only have lost the time and gas I burned.

Bob

I'm certainly no expert, but from your description, there appears to be nothing wrong with the tranny. You say it shifts at the right time, and with no noticeable delay or clunk. Have you considered "drive line play"? In other words, if a CV joint has play in it, the tranny will appear to clunk as the slack is taken up. This is particularly noticeable when going from drive to reverse with brakes applied. Just a thought!

I have been under the car with it up and when the shifter is moved between reverse and park it the sound seems to actually come from the transmission itself. I will take another look, but even though it is shifting at the correct RPM torque points, it is definitely not right. Much too harsh and I suspect this is what is causing the noise. This is why I thought that the "reverse slam" was a good description. It does seem to be "slamming" into gear too abruptly but this is with all gears, not just reverse and that is why I was not sure if it was the same thing.

(Hopefully) Final Update on my '96 Transmission problem (the trans was shifting extremely harshly between all gears and even when going from Park to Reverse):

The lower motor mounts looked good - the engine moved less than 1/2" laterally even during the harsh shifting, so I decided to go into the TAAT transmission through the top valve body cover (which is located under the

12V battery holder).

After removing the outer cover (13 bolts) and then removing 19 more bolts that held the internal solenoid cover in place, I was able to remove the solenoids themselves. There were 5 in total and 4 of them measured 4.4 to

4.5 ohms each which agreed with the information that Bill Biggs had provided (they should be 4-6 ohms when "cold"). The 5th solenoid however measured just 0.6 ohms so appears to have an internal short. This solenoid is the last in the string nearest the front of the vehicle and I presume the one that modulates the fluid pressure. Since it was not working, the shifts were getting full pressure which almost certainly would have caused a catastrophic problem if we had continued to drive the vehicle and ignored the "clunking" noise.

I plan to pick up a replacement solenoid tomorrow at the dealer along with a new cover gasket and then put it all back together and have it back on the road sometime later this week. Special thanks to Bill Biggs ( a.k.a. webacraft on the SaturnFans Forum) for his assistance and to Blah Blah, Steve, and Curmudgeon for their replies.

I hope that this thread may help someone else down the road if they experience the same problem.

Bob