upgrade
Senior User
Joined: May 2001
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not sure why you'de want to swap I have 3.55's & tow a 31' 8000# + TT on a regular basis. just drop down to 4th as soon as her nose goes up & I get the same gearing as if I had 4.10s & still get the mileage benifit of the taller gears when mt which happens to be a lot more than not.
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Joined: May 2001
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From: Cabot, Arkansas
Originally Posted by dorsetmerv
How much will it cost if i get a garage to upgrade my rear 3.55 axel on my f250 to a 4.1 to increase my towing capacity?
many thanks guys.
many thanks guys.
Post Fiend
Joined: Nov 2003
Posts: 21,285
Likes: 16
From: Nutter Fort, WV
You don't want to know how much I tow with 3.55's and 33" tires on a regular basis, but it is over 20,000 gross here in the mountains with a 4 speed manual.
The only thing that would benifit from lower axle ratios is the U joint and driveshaft life.
With fuel prices I can afford to replace them rather often since I still get reasonable MPG's when running empty.
After looking at the numbers I guess it would not be that bad with a ZF 5 to go to 4.10's, 2400 would be 70 MPH with 31" tires. Still your MPG's will take a hit if you do much freeway driving.
The only thing that would benifit from lower axle ratios is the U joint and driveshaft life.
With fuel prices I can afford to replace them rather often since I still get reasonable MPG's when running empty.
After looking at the numbers I guess it would not be that bad with a ZF 5 to go to 4.10's, 2400 would be 70 MPH with 31" tires. Still your MPG's will take a hit if you do much freeway driving.
Post Fiend
Joined: Nov 2003
Posts: 21,285
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From: Nutter Fort, WV
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Post Fiend
Joined: Nov 2003
Posts: 21,285
Likes: 16
From: Nutter Fort, WV
Well since I was averaging 10 before the IP swap last weekend I am happy again.
33" tires and a T19 with 3.55's = 2650 RPM at 70 MPH
I don't think a ZF 5 could stand what I do with my truck for very long.
I would like to drop the RPM at highway speeds, but I like my indestructable cast iron transmission.
I am holding out for a ZF 6 after I can rework the dash and rear axle swap so I can have a speedo.
33" tires and a T19 with 3.55's = 2650 RPM at 70 MPH
I don't think a ZF 5 could stand what I do with my truck for very long.
I would like to drop the RPM at highway speeds, but I like my indestructable cast iron transmission.
I am holding out for a ZF 6 after I can rework the dash and rear axle swap so I can have a speedo.
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