93 Buick Regal Custom 3800 liter automatic transmission trouble

190000 miles

Driving on the highway my car began to vibrate and lose speed. I had to shift out of overdrive before I could get the car to respond again. It continued to feel incredibly impeded. I could not push the car over 65mph and couldn’t remain at speed going uphill. From a dead stop, the car accelerates incredibly slow in any gear. The engine feels impeded even in P and N almost like the trans does not disengage. The trans will downshift and kick up RPM when pedal is put to the floor like normal. Any ideas as to what could be causing the trouble and how much it could cost to have repaired? I have checked the trans fluid in park at op temp and it’s perfect. No fluid is leaking from the car. Car feels like it’s in drive and I’m holding the brakes while hitting the gas… even in P and N so I don’t think it could be brakes.

Thanks
Sam

Find a good independent non-chain shop to check it out:

I don’t think it is your transmission, I think it is the engine. Your engine has simply lost power. Could be as simple as a clogged air filter, broken vacuum line, sparkplugs or as costly as a bad intake manifold gasket or head gasket.