My friend has a 1996 honda civic with an automatic transmission, the car runs good for 20 minutes, but once the transmission get hot, it won't move forward or backwards.

He's changed the fluid in the transmission and that's doesn't seem to have helped. Is there a transmission filter to change that would solve this problem, or what else could it be. Thanks in advance!

 

Sounds to me like the torque convertor is locking up. Time for a new tranny.
What fluid are you using?

 

I'd tend to agree.

You likely could get a bit more time out of it with a good servicing, but it's unlikely to last long.

 

You can find an auto tranny for dirt cheap. Swap a new one in and call it a day. I personally have never seen an auto tranny lock up or go bad unless it was filled with the wrong fluid, not serviced properly, or run dry.

 

I told my friend, he doesn't have a problem pulling the tranny out.

There are a few bone-yards in the area, that include a 6 month warranty on the parts you pull. He really didn't know what the problem could be.

I thank you all for the quick replies, at least we know which direction to go in. Thanks again!