The 3 speed Automatic tranny in my 1990 f350 dually with a 7.3 Diesel has seen better days. Can I upgrade to a allision 5 or six speed, or get another gear on the highway side of traviling in this gem of mine??????

Thanks

 

you can find info on allison transmissions on the web. there are several that will work for you. all the six speed units use trans controls and are more expensive. the at 545 is a all hydraulic 4 speed unit found in school bus and medium duty trucks it can be shifted with simple linkage or with electro/air shifter. the problem is geting the sae 3 bell and trans into the truck. it is rated at 235 hp and 445 torq with a gvw 30,000 lbs. I have been told this unit is under rated and will take 25% more power in a lighter rig like a F 350. I have seen a at 545 Dodge combo tow rig the guy said he loved it. Good Luck.

 

u can step up to the e4od and get a stand alone controller. or swap to manual 5 speed.

 

dont consider the e4od that is what junks most of these trucks. The 5speed swap is the best way to go. If you really want an auto you can get an at545 from an international bus or truck its a great trans i have several of them in chevys. Cost is much less than 5 speed you should be able to get everything for under 500 but you may have to run a body lift to get it under there.