Transmission question - need some wisdom

[Pruitte27]

Hey y'all

Just bought a 91 F350 (7.3L, 4wd dually, automatic) last month and I'm having a little trouble with my shift from 1st to 2nd. As far as I know these came stock with a 3 speed vacuum shifted tranny (C6 I believe). From what I can tell a previous owner has done a tranny swap to the E4OD transmissions which were in broncos and possibly e350's at the time. When I drive the truck, it does not shift until about 3 grand rpm's which leads to a hard shift. I bought the truck to haul my horses with, but really don't want to haul anything with it until this is fixed. I know on the stock transmissions there is a vacuum modulator on the transmission which can go bad and cause this to happen, but I'm not as familiar with the electronically shifted trannys and need some advice. My thought is it's either a solenoid or the clutch pack is going bad, but I really don't want to replace/rebuild the transmission unless I have to. Does anyone know any tests or had this problem before that had found the issue and corrected it? Thanks in advance

Jake

 

[Pruitte27]

Anyone??

 

[blacksnapon]

sounds like forward clutch, sorry!

 

[Bedlinedf250]

Are you willing to buy a new tranny. I had a similar issue but would do it after 40. Rebuilt the tranny to a heavy duty 4r100 version with nothing being fixed. Luckily the guy had a reputation and gave me a 2 year warranty. Took him almost 6 months to get it goin normally again. Last thing he did was replace the case meaning the shell. Couldn't explain it but once all the parts were put into a new case ran like a champ and it's been almost 3years of heavy hauling.