flush first is my recommendation.

Roy

Answered by ASEMaster6371 (expert)
24,845 answers provided

Disconnect cooler supply line and pour new transmission fluid in. Put pan underneath cooler line and turn on engine. Transmission fluid flows in pan as I continue to add new transmission fluid and old transmission fluid comes out of cooler supply line until new transmission fluid shows coming out stop engine. Then I should drop transmission pan and change filter and gasket and loose some new transmission fluid just poured in to flush out old fluid. Then top off to required level. Is this how it is done? Thanks.

P.S. both vehicles have over 100,000 miles and never had flush done.

Response from roycar71
27 questions asked

no. you need the actual machine that circulates the fluids. when you do it this way, you starve the main shaft of lube with an open cooler line.

Roy

Answered by ASEMaster6371 (expert)
24,845 answers provided