Thank you for your time and opinions in advance.
*Newly acquired from 1 owner, Slick La Sabre with 122K.
*Owner recorded every fill-up/service in book in Glove box.
All but Plugs and Transmission service.
Drove Car for the last month with no issues, tranny shifted great, no slippage put around 2K on it miles on car.
*Today I Dropped the tranny pan, Changed filter, flushed out T-cooler coil..then Refilled with Shell Universal. Pan was exceptionally clean..Some material on magnet..some on bottom, but in all good shape for -20Year/122K car- Fluid was dirty but in no way had burn smell to it. Cleaned it out then reassembled/adding filter & fluid.
Drove 5 miles, it ran shifted great (BETTER), no slippage.. stopped was 1/2 quart low. (left it running) and topped it off drove it 3 miles...stopped added about 1/2 pint to finally top it off, then drove it home (7miles) checked level..OK (While it was still running). Got back in to head to town and pulled it down into drive and now it will not shift out of 1st.
*Any combinations of gear selector movement or Engine RPM has no effect. Reverse works great no slip just like 1st. Will not shift out of 1st!
The Day before... I did replace the thermostat that had been stuck open for the last 6 years. (Lady said she hadnt had a heater in 6 years..
*1st day really above 80dg here and the Radiator Fan kicked on an ran today at idle for first time I've ever heard at about the same time I stopped and checked the fluid level for the final time....coincidence??
91 Buick LaSabre Custom
A Clean 122K