interchangeabilty question
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New User
Joined: Nov 2010
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From: cleburne tx
interchangeabilty question
hello guys i was wondering if any one has ever changed a f250 over to a f150 drive train? My truck is a 1984 ford f250 with 373 rear end gears and i was thinking about changing truck over to a 1/2 ton 9 inch rear end and the same with front end i know the front i beams and disk look to be the only thing different up front. I would like to keep the f250 leaf springs but i rarely haul anything with this truck and the 373 gears and granny transmission is killing me on fuel prices truck runs about 2500 at just 55 mpg.
anything you all can suggest would be a help i know i can just buy a half ton but this truck is in fairly good shape just really bad mpg even with a 4.9 gets maybe 12 mpg
anything you all can suggest would be a help i know i can just buy a half ton but this truck is in fairly good shape just really bad mpg even with a 4.9 gets maybe 12 mpg
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Joined: Jan 2001
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From: Virginia
If it's 4x4, the f150 stuff won't fit. The f150 4x4 beams are longer than the f250 4x4 beams, and they are made different on the end, since one takes leaf springs and the other coils.
Your easiest solution is to swap in a zf 5 speed transmission with overdrive. I just did this with my 89 diesel and it's a great swap when you are traveling the interstate. It also gave me 3 more mpg, and it's so much quieter when cruising down the road in OD.
You could also keep what you have, and hunt around for a used gear vendors overdrive unit. They make models to fit behind the transfer case, and I think some fit in front of it also. New they are very expensive,(2500?) and used they are around $1000.
Your cheapest solution would be to buy a f250 with a 351w, 4.9, that had a zf, swap it in your truck, and you could put the 4 speed in the old truck and re-sell it and get some of your money back.
Your easiest solution is to swap in a zf 5 speed transmission with overdrive. I just did this with my 89 diesel and it's a great swap when you are traveling the interstate. It also gave me 3 more mpg, and it's so much quieter when cruising down the road in OD.
You could also keep what you have, and hunt around for a used gear vendors overdrive unit. They make models to fit behind the transfer case, and I think some fit in front of it also. New they are very expensive,(2500?) and used they are around $1000.
Your cheapest solution would be to buy a f250 with a 351w, 4.9, that had a zf, swap it in your truck, and you could put the 4 speed in the old truck and re-sell it and get some of your money back.
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New User
Joined: Nov 2010
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From: cleburne tx
ya i have been thinking about just changing the transmission to ether a 5 speed or a c6 or maybe a aod but the aod is really expensive found rebuilt ones for 700 plus all the extra stuff to go to auto trans to get lower rpms my brother told me to chain my ford to a chevy to save on gas but he is a chevy nut
thanks for your help
thanks for your help
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New User
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From: cleburne tx
Ya it is a 2wd and have thought about trying to find a higher geared rearend i might go down to local salvage and see what they say about a trade mine low gear for there high gear days like this make me wish it had a 9 inch would be so much easyer to change gearing
Cargo Master
Joined: Apr 2010
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From: Acworth, GA
I have a 3.08 rear end in my truck. It is a 2wd, 300ci, with a man. 4sp OD. I get about 17mpg city and 20mpg hwy. In mine 1st is like a granny gear.
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Post Fiend
Joined: Dec 2007
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From: Lost
If you have a 2wd F250, and it's not the HD version, then swapping in F150 I-beams and rear axle could be done somewhat easily.
But, in all honesty, it would make more sense to just swap in a higher ratio rearend. Even a 3.55 rearend, combined with the taller tires used on the F250, would make it get better MPG on the highway. Plus it would be a lot less effort to swap than both the front and rear axles.
Granted, the taller 16" tires tend to have a bit more rolling resistance than the 15" tires used on F150's, so that could hinder the overall gains.
But, in all honesty, it would make more sense to just swap in a higher ratio rearend. Even a 3.55 rearend, combined with the taller tires used on the F250, would make it get better MPG on the highway. Plus it would be a lot less effort to swap than both the front and rear axles.
Granted, the taller 16" tires tend to have a bit more rolling resistance than the 15" tires used on F150's, so that could hinder the overall gains.
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Post Fiend
Joined: Dec 2007
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From: Lost
Very true. Most likely it drop 1-2MPG from what it gets with the 4 speed, since the auto doesn't have a solid connection like the clutch, and allows a small percent of loss.
Cargo Master
Joined: Mar 2007
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From: Arcadia, Fla
Which rear end is in you truck right now? Semi floating or full floating axle? Hit the you-pull-its and you probly get a whole axle probly under $400 depending the yard.
Also get some light truck tires(LT###R##16) and pump them up to sidewall rateing(usually 80psi) and they roll along time but you will loose some ride quality with those hard tires.
I love my 84 F250 can't wait to get it back on the road
Also get some light truck tires(LT###R##16) and pump them up to sidewall rateing(usually 80psi) and they roll along time but you will loose some ride quality with those hard tires.
I love my 84 F250 can't wait to get it back on the road
Posting Guru
Joined: Sep 2006
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^^^^ How much driving is he going to have to do to recoup that money though. If he desperately wants better fuel economy he should seriously get a cheap car that gets better economy not butcher down a perfectly good truck.
Post Fiend
Joined: Jul 2004
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From: Northern California
Reducing the hauling weight or GVWR of a vehicle is also ilegal. The same applies to putting smaller brakes on a vehicle.
You can upgrade and go larger, but you cannot downgrade and go smaller legally.
You can upgrade and go larger, but you cannot downgrade and go smaller legally.
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