DumbGenius

Hello,

recently my 2000 GS400 has begun to show strange symptoms in the morning.

1st symptom-clicking or clunking when I shift to reverse or drive. The noise eventually dims as car is warm.
2nd- when I put into drive the idle is low and vibrating. When in park and neutral the rpms are nice and strong, in drive it eventually gets low as 2-3 rpms. At stops it will have a range of motion, up and down similar to if it were a problem with TPS.
3rd- when accelerating from a dead stop, when the RPMS get around 9 rpms I feel a wobbling vibration type of sensation. I want to say if feels like the transmission is not fully engaged. This symptom dims as I gain speed and momentum and also when the car reaches operating temperature.
4th- only occurs occasionally after the previous symptoms, when arriving at a stop the car will violently shake as if it’s struggling to run. Similar to a misfire or timing issue.
5th-when AC is turned on it reduces symptoms as well.
6th- if I slam on breaks, or suddenly slow down the transmission disengages temporarily as if I put it in neutral, then re-engages after a 2 second delay. (This happens at all times, warm or cold.)

Based on my research most signs point to transmission/engine mounts, however the one thing that makes me skeptical is that the symptoms mostly disappear when car reaches operating temperature.

recent work-(Within past 2 years) timing belt has been replaced, spark plugs replaced, Throttle body assembly replaced (including TPS I believe.) I use all OEM parts in my repairs and performed by a licensed mechanic.

‘recently did a seafoam treatment. My emergency break was non operable for a long time, and possibly put added pressure on transmission and mounts. I have since fixed the breaking system.

have not done the fluid check or replace yet. But will obviously be my next step. So ladies and gentlemen, thoughts?

kevin3344

This may or may not be your issue, but I had a similar problem on my '99 GS400. Very low rpms and sometimes they would fluctuate. Everything was fine when in park. Coming to an abrupt stop sometimes caused it to stall or shake similar to a misfire - but it was only after the car was warmed up. There was no CEL either. After much research it turned out to be a vacuum leak...I found a cracked hose under the engine cover. Take the four bolts off and examine all of your hoses for signs of cracking. As for the clunk when switching to reverse or drive that could in fact be your motor mounts. When I replaced mine the car drove a lot smoother.

DumbGenius

thank you for your contribution, I think that is very helpful. I will take a gander at my hoses, and I’m pretty much sold on the fact I need engine/transmission mounts. The car is 20 years old and I have never replaced them in the 7-8 years I’ve owned her.

DumbGenius

So batter is dead this morning before heading to work. Reading that it is possible for bad/low battery to cause intermittent transmission issues. Let’s hope !

DumbGenius

Thanks for input