transmission need help .

my truck 2010 tundra 5.7 after my transmission cooler broken i install new one on .i refill trans with Toyota fluid but i don't why my truck lost revere gear .i can drive forward but no revere .can you tell me what wrong? Thank you

 

Did you get the level correct? Have heard that these transmissions are very particular about the level. If over or under filled it could have created the problem.
Welcome from TX.

 

yes i did when engine idle i open small bolt at trans pan.

 

I don’t think the level is supposed to be checked when the truck is running.

 

Yes engine On but must know trans fluid temp and it needs to be about 115 degrees - barely warm - I'd use a trans fluid reader like Torque for example to avoid goofing around with pinning things. You'll see what I mean, read here, especially post #16: https://www.tundras.com/threads/transmission-drain-and-fill-help.48855/

 

Doubtful a level correction is going to be the fix. It could be coincidental or a result of your recent cooler issue.
Its probably time to call a few transmission shops that are familiar with the Tundras and discuss your issue. Hopefully one can offer a solution.
Good luck!

 

Transmission temp MUST be between 115F-130F and have the cooler thermostat pinned open for a correct level. Do it on a level surface.