'94 Lexus Ls400 Transmission

[JDee]

My '94 Lexus has about 200,000 miles on it. The transmission generally works smoothly, but occasionally when I put it in gear, the car sort of jerks as the transmission engages. Once I am on the road, everything always works well. This issue is intermittent. Most of the time the transmission slips into gear smoothly. I checked the transmission oil level and all is well there.

A friend mentioned having the transmission cables or linkage checked. He said they might need tightening.

Can anyone tell me what is happening and how to resolve the issue?

[sha4000]

If fluid level is correct and the fluid is still red and not brown/black then most likely you need a new transmission mount. When you change the mount the old one will probably fall apart, especially after 20+ years and 200k miles. The good news is that the part is cheap and you can change it yourself.

http://www.clublexus.com/forums/ls400/450071-diy-engine-and-transmission-bushings-replacement.html

[VBdenny]

Mounts are rubber and it gets hard, cracks and allows the transmission to move slightly upon torque. Probably not a bad time to do a drain and fill on the transmission. I bought a case of Toyota transmission fluid and luckily, there is a drain plug. Drained, measured, refilled, drove, drained, refilled etc. Took 4 times to go through the case. Car now has over 200,000m and shifts like new WITH the original mount. Go figure.

[landar]

Welcome Jay!

Good advice on the transmission mount. However, I want to point out that it is not always easy to determine the level. Sometimes it looks proper but could be 1/2 qt low. Especially if it does this only when cold, first thing in the morning. If so, you might consider adding 1/2 a qt and seeing what happens. It won't kill your tranny even if a 1/2 qt high. And as VBdenny points out, may be time to change your fluid.

[JDee]

Thank for the suggestions! The transmission mount has been replaced. While the issue is better, it still jerks occasionally, though less frequently. What else could be causing it?

[Exhaustgases]

A sticky torque converter clutch could. Or somehow it gets some pressure past a leaking valve or partially stuck solenoid.

Also there could be material flaking off the clutch and it gets partially wedged and allows the clutch to be slightly engaged. But that would have it doing the jerk all the time.