Hey guys, I'm new to the site as well as trucks. I've spent a lot of my adult life in Mustangs. Recently I bought an 89 f250, with a 351w and someone had swapped the manual transmission for a 3 speed auto.

I had the truck for a week, when I let my cousin drive it and he blew the motor. I'd like to be able to put the original tranny in when I redo the motor, or put a 460 in, but unsure of a tranny. I know I want more than 3 gears. Any help on this would be awesome. Thank u.

 

My old 89 came with a 351W and ZF 5-speed, so I'm guessing yours did, too. I can't tell you what you're getting yourself into if you decide to upsize to a 460, but I do know that there were different configurations of the tranny depending on the engine, so make sure you get a ZF made to bolt up to the specific engine you choose.

Perhaps another option would be to throw a Gear Vendors Overdrive unit on the tranny you have? If it's a 3-speed auto, it's likely the C6 which is a great transmission from a reliability and cost standpoint.

Mike

 

Thanks Mike. My big thing is to be able to run down the road at 60 mph and not have the engine screaming the whole time. Right now with the c6 it runs at 3000 rpm at 58 mph. I'm thinking that if I put a five speed back in it I can maybe run 2200 at 60. Any clues as to where I can get a used zf5 at a decent price, since now money I had set aside for the truck has to go into a new motor?

 

wth a 460 swap youll be at 2700 at 65

 

Well, your RPM is obviously gonna depend on a few factors, including the tranny and (more importantly) the rear end ratio.

My current truck (see sig) has a 3.55 rear and a ZF 5-speed. At 65, I'm turning around 2K RPM. IIRC, that was about the same on my old 89 with the 351 and the ZF and the 3.55 rear.

As to where to find a tranny, it's pretty popular so it shouldn't be all that hard. They're also notoriously reliable, so a junkyard unit may do just fine.

Mike

 

I recently bought a very low miled 460 and a zf5 for $450

 

craigslist is your friend.. quick search and i found a parts truck with a 460 in it.. tranny unkown.. may start there to see what other people have around you before you decide to go to a junkyard.. if you do go to junkyards chances are the truck is going to be stripped to the bone and many parts will be missing off the motor.. unless you just get lucky..

 

Thanks guys.... the more I think about it, I think I will just replace the 5.8 and go with a zf 5-speed. As far as cost, that seems to be the way to go.... I will most deff look into my rear-end gears. 3.55s or 3.73s seem to be the way to go. It's my understanding that there is a few different rearend sizes. Is there a way I can find out what size it is?

 

Ford Axle Code Chart .: Articles Look at the axle code on the drivers door sticker and compare with this chart (ignore where it says 1991).

 

I don't think 3.73s were an option on the truck. It'll likely either be 3.55 or 4.10

Mike