'87 Cutlass 2004R Trans issue/Concern

[TedH]

A gal I know from where I sing karaoke advises that the 2004R in her Cutlass is starting to fail in Reverse. She suspects the trans may require rebuild as another Olds she had at about this mileage (87k miles) experienced a 2004R failure and she had it rebuilt (about 15 years ago). Is there anything short of a rebuild (perhaps fluid and filter?) that may help?

[307caprice2nv]

My 87 Cutlass with a 2004R started doing that when I first got it 5 years ago at about 184,000km's. It would usually delay going into reverse after driving it hard or driving it at highways speeds for a while. The fluid still looked clean and good color but it was bubbling up. I eventually figured out the stock 305 was also running hot (up to 240 degrees on highway trips) and the lockup torque converter wasn't working. I put a good external trans cooler on which almost 100% solved the delayed reverse and bubbling trans fluid. Eventually replaced the rad with a good aluminum one which fixed the engine running hot. Then the car got parked due to rust underneath and I pulled the engine out of it. Later on my other car got wrote off and I had no choice but to put the motor back in the Cutlass and drive it. After reinstalling it the lockup worked again, and the transmission has worked perfect up until I parked it a few weeks ago with over 300,000km's on it and I've driven it really hard and raced it. Fluid still looks nice and red and will chirp the 1-2 shift at WOT. I think it's possible that some of these transmissions get rebuilt unnecessarily when the delayed reverse is due to an overheating problem. Anyone else seen this?