Tranny thump going to reverse gear

[71GTJ]

96 Avalon-------Not so much into drive. Maybe RPM too high?

[BonzoGonzo]

set brakes. have someone torque it up in reverse and drive as you watch. if it moves much, check motor mounts

[pmesfun]

Yeah, mine does it too, only when warmed up. I've checked the motor mounts, all looked fine. I asked this question a while back and someone mentioned cv axles. I think the front motor mount is probably my problem.

[71GTJ]

Motor does not move much in gear.I was told that if rpm is above 800 and go into reverse you will get that thump. So if engine has not warmed up enough to decrease the rpm below 800 than your thermostat is stuck open or does not close all the way. Can anyone out there confirm or reject this theory.

[BonzoGonzo]

certi... he77, i can't even spell it! but OH LA LA!!

take a couple thousand and pay one of them, ok?

now that i know your requirements, i'll not bother you with my amateur responses. promise.

[71GTJ]

Hey BonzoGonzo, I've edited my previous question. No requirements. I wish i had a thousand!!!!

[BonzoGonzo]

Originally Posted by 71GTJ

Hey BonzoGonzo, I've edited my previous question. No requirements. I wish i had a thousand!!!!

my car goes ito reverse at 1000 rpm or better, every day when she is cold...

how does your trans fluid look? is it burnt (black) with gritty looking stuff in it? often times old, worn-out fluid will cause rough shifting, of all kinds...

changing the trand fluid is a PITA... can't do it all at once. first unbolt the pan, clean it inside, install new filter (being CAREFUL not to over-tighten the bolts for the filter, as they also hold the valve body on) and replace the pan.

now you can start draining 2 quarts of fluid every time you change your oil, via the drain plug in the bottom of the tranny pan. it will take quite a while for this to replace the fluid. pep boys will power flush it for about $150...

[71GTJ]

Tranny fluid looks clean, drives great. Just that it takes so long to warm up, which means the revs are above a 1000. I've waited over 5min. for the revs to reach about 750, then no thump going into reverse. What could cause this delay?

[BonzoGonzo]

Originally Posted by 71GTJ

Tranny fluid looks clean, drives great. Just that it takes so long to warm up, which means the revs are above a 1000. I've waited over 5min. for the revs to reach about 750, then no thump going into reverse. What could cause this delay?

The thermostat would be the next suspect. I think there are some vacuum switches that operate as the engine warms, but I don't see how they could be causing this...

Thermostat is not toooo hard to do - remove air cleaner, battery, etc. etc. etc. Use an extension to reach the bolts. Drain some antifreeze out first... just about like any other car. Lots of wiring plugs to unhook... You can do it in about an hour.