Rear End Swap
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Rear End Swap
Hi, I just purchsed a 1996 F250 PS. It is a standard that came with the 4.10 ratio rear end. Since I don't pull very much, I'd like to swap it out for the 3.73. I had a 1997 PS with a 3.73 and it got a lot better gas milage (the 4.10 is only giving me 14 MPH on the freeway). Ford started using the 3.73 in 1997. Does anyone know if a complete axel swap will work? Also, does anyone have an opinion of the 3.55 ratio rear end (i.e how much towing capacity will I lose?)
Thanks for any input,
Flyyboy (Bryan)
Thanks for any input,
Flyyboy (Bryan)
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Joined: Jul 2008
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From: Thomasville, GA
I swapped from a 4.10 dually rear end to a 3.55 single wheel and with a stock truck I hated the 3.55's.
But I love having them now, with my Stage I injectors and chip and the mods in my signature. I get 20mpg highway and still can tow quite well. Tow a 19 foot boat pretty often, towed my wife's cobalt on a trailer with 2k in the bed across I-40 from NC to Oregon with no problems, and the pic in my sig had about 4k pounds of hay in the bed plus had a 20ft flatbed trailer behind it with at least 2 tons more and it pulled it fine.
It's a lot easier to find 3.55's than 3.73's (they mostly used them in '99+ superduties and the axles have a different wheel bolt pattern).
Directly swapping the axle is easy. WHen I did mine we just unhooked the driveline, unbolted the springs and brake lines and swapped it springs and all.
But I love having them now, with my Stage I injectors and chip and the mods in my signature. I get 20mpg highway and still can tow quite well. Tow a 19 foot boat pretty often, towed my wife's cobalt on a trailer with 2k in the bed across I-40 from NC to Oregon with no problems, and the pic in my sig had about 4k pounds of hay in the bed plus had a 20ft flatbed trailer behind it with at least 2 tons more and it pulled it fine.
It's a lot easier to find 3.55's than 3.73's (they mostly used them in '99+ superduties and the axles have a different wheel bolt pattern).
Directly swapping the axle is easy. WHen I did mine we just unhooked the driveline, unbolted the springs and brake lines and swapped it springs and all.
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Joined: Feb 2009
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From: Plankinton, SD
Ya, ford didn't offer the 3.73's in these trucks. Not till 99. Like Evan said, swapping an axle is easy if you want to go to 3.55's, but you need to change ring and pinions to get 3.73's. I like my 3.55's with more power I have now too, pulling and all. But I would like 3.73's someday. It's up to you, if you tow much and are stock, the 3.55's aren't the best for sure.
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Joined: Nov 2009
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From: Denver, CO
Ya I thought the OBS's were all 3.55's or 4.10's, I just swapped to the 4.10's due to a larger tire but with the 3.55's and 285 tires I pulled my gooser with my buggy no problem granted I hadeII's and other mods. swap should work streight up if front matches as well
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From: metairie, LA
i hpe i am not hijacking to bad, but here goes.... will a super duty rearend fit our trucks without to much work? i ask because of the disc breaks And the factory 3:73's and i know the lug pattern is differnt. can the front rotors also be used from a super duty? super duty wheels are a dime a dozen around here and obs are not
on edit: the 2000 superduty and my 92 call for the same front wheel bearings
on edit: the 2000 superduty and my 92 call for the same front wheel bearings
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Joined: Jul 2008
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From: Thomasville, GA
Yeah, I'm not sure how well mine will do if I swap to 315's after my 4x4 swap... Might have to stick with 285's
George, I am pretty sure the 10.5 rear will bolt on pretty easy, I thought about getting a matching front and rear from a SD to do my 4x4 swap, but ended up getting that Dana 60 from a '94 for $350... with matching gears to my rear end!
George, I am pretty sure the 10.5 rear will bolt on pretty easy, I thought about getting a matching front and rear from a SD to do my 4x4 swap, but ended up getting that Dana 60 from a '94 for $350... with matching gears to my rear end!
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From: Maryland
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Cargo Master
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I wouldn't recommend driving that slowly on the freeway.
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Joined: Jul 2008
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From: Thomasville, GA
How fast are you driving on the freeway and only getting 14 mpg? When mine was a dually with 4.10's I was still getting 18mpg highway, and I got between 14-15 mpg towing a car and with a canopy and 2,000 pounds in the bed going across the country doing 70mph the whole way with 3.55's...
14mpg seems low even for 4.10's...
14mpg seems low even for 4.10's...
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Thanks everyone.
Brownie, I just drove from Denver to Houston running 75 to 80 mph and got an average og 14.5 mpg. My RPM were about 2500. When I had my 1997 F250 PSD I got at least 18 mpg. The 1997 did have the 373's. It was the first year for that option on the f250 PSD. I guess since it was not an option for the 1996, I might need to go with the 355's. I was hopping to use the 373's and not sacrifice too much towing capacity.
Brownie, I just drove from Denver to Houston running 75 to 80 mph and got an average og 14.5 mpg. My RPM were about 2500. When I had my 1997 F250 PSD I got at least 18 mpg. The 1997 did have the 373's. It was the first year for that option on the f250 PSD. I guess since it was not an option for the 1996, I might need to go with the 355's. I was hopping to use the 373's and not sacrifice too much towing capacity.
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Joined: Dec 2003
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From: socal
My F-superduty (F450) PSD and 4.88 R&P I avg 16 mpg rolling 2000-2200 RPM 48-50 MPH on the freeway, yes I get flipped off a lot! I want to regear to 3.55 also but you guys say they suck with a stock motor? 3.73 would be cheaper (no carrier change dana 80) but would that net me the best MPG?
Flyboy, with 4.10 wouldnt a taller tire get you close to 3.73? Like a 285?
Flyboy, with 4.10 wouldnt a taller tire get you close to 3.73? Like a 285?