Can''t back up

I have a 1990 camry 4cly,auto,200,000+miles Will not go into rev. All other gear seem to be ok. When I put it in rev. you can feel it change to that gear but will not move no matter how much gas you give it. filter changed about 45 days ago and looks clean on the stick. Need HELP

Could be the 1 to 2 or 2 to 3 shift valve.  If so the valve can be removed for cleaning.

Or a clutch, brake, etc. This requires removing the transmission.

Thanks, Where do I find the valves for cleaning? Are this elect. valves or spring ball valves?

Can''t post over 1 line without getting an error message.

Check your private messages for a link.  Go to Gen 2 section of link for trans info.

Check drivers side door for sticker with trans model number.

Could be A140E or A140L (or maybe H).

If A140E, trans has electric shift solenoids but don''t think this is the problem.

If may be the manual shift valves inside the valve body bolted to bottom of trans.

Get the trans info from the link and find your trans model.

Best I can do typing only one line at a time.