intermittant transmission vibration in drive

[jrcowboys]

Guys:

I have intermittant transmission vibration (you can feel it in steering wheel)when the car is in drive at idle. Seems to be worst during warm up. Car is 1999 Lexus SC300 with 156K miles and I use M-1 Multi-Vehicle transmission fluid. Owner manual calls for Dexron II or III. Transmission shifts perfectly. Note: I partly change fluid yearly by sucking out two quarts(thats all I can get out) and the fluid looks very good (light pink).

Possible causes:

-transmission fluid too heavy causing torque converter to engage
-Motor mounts loose
-idle set too high (seems about right)

Any thoughts?

JR

 

[tig1]

Motor mount. Since Mobil 1 ATF is rated Dexron, it won't be the fluid. Maybe it's time for a spark plug change.

 

[OVERKILL]

Sounds like a motor mount, or the exhaust hitting something.

 

[Radman]

1 - Motor mount
2 - Transmission mount
3 - Engine vibration dampner

 

[mechtech2]

The trans is the last thing I would think causes this.
Misfiring or other cylinder uneveness is the problem.
Bad mounts make things worse - you feel it more.
Vacuum leaks are a candidate. so is general tune up stuff.