My 1994 Mark viii slips when the car has been sitting overnight. It only slips in 1st, it acts like it doesn't catch 1st gear. It usually only slips 2 or 3 times until the transmission is up to operating temperature and then it works fine, until it sits overnight. It seems as if it is the tranny fluid pump is loosing its prime from sitting overnight. All the 1-2 piston conversion symptoms describe slipping from 1 to 2, could this still be the problem?

Yep. Change the fluid, accumulators and springs. That should be done with or without symptoms. Also switch to Mercon V fluid...

+1. I went through 3 4r70w's that started with the same symptoms.

flush the system drop the pan add some lucas additive

Ya we have done that no change I have ordered all the parts form ford and we are going to replace the 1-2 and 2-3 pistons and do a j-mod at the same time. I will keep you guys posted thank you for your input.

+1. I went through 3 4r70w's that started with the same symptoms.

WOW! look who is back. Long time no threads.

WOW! look who is back. Long time no threads.

Thats what I thought, a fellow post whore return's! :D

well its done for found one out of a 98 with 7,000 miles for $600 can any one tell me what all i need to do to put it in my 94?

Thanks Adam

You'll need to play with the wiring harness.

http://www.tccoa.com/articles/tranny/transmission/page16.shtml