Automatic Transmission

I own a 2000 Buick LeSabre with over 110000 miles. Recently it has developed minor shift problems. My mechanic changed the transmission oil and added a additive which he says will clean the valve body. It is working better since he did this (about 2 months).

I have used Marvel Mystery Oil in both the crankcase and gas tank with apparently no ill effects. Can it be used at all in the transmission?


I wouldn’t put anything other than automatic transmission fluid in an automatic transmission.

I wouldnt use Marvel. If you want to use an additive, use Lube-Gard, the one in the RED bottle.

What kind of shifting problems are you having??