Gears?
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Junior User
Joined: Jun 2003
Posts: 83
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From: Rome, Italy
Gears?
After I switched my 84' F250 from a 2x4 to a 4x4 with the use of an 83 F 250 suspension and frame I need to match up my gears. The front off the 83 has a DANA 50 with 3:54 gears, the rear (off my 84) has 3:73 gears. I know I need to match them up before I start running the 4x4, so here is the question.
I want a little better MPG, right now as a 2wd w C6 Auto I get about 11 MPG ( last figured it out before I did the switch) I have a Berg Warner 4 speed tranny that I am prepating to put in with the original 84' 460. I plan to run stock or slightly larger tires on the truck ( no big mudders) the biggest would be 32x11.50. Given all this, should I switch my rear end from 3:73 to 3:54, or the front from 3:54 to 3: 73. I haven't seen 3:73s for the Dana 50 yet, and I don't know what the rear is. I have been trying to ID it but can't find any identifying numbers my best guess is a Dana 44.
I want a little better MPG, right now as a 2wd w C6 Auto I get about 11 MPG ( last figured it out before I did the switch) I have a Berg Warner 4 speed tranny that I am prepating to put in with the original 84' 460. I plan to run stock or slightly larger tires on the truck ( no big mudders) the biggest would be 32x11.50. Given all this, should I switch my rear end from 3:73 to 3:54, or the front from 3:54 to 3: 73. I haven't seen 3:73s for the Dana 50 yet, and I don't know what the rear is. I have been trying to ID it but can't find any identifying numbers my best guess is a Dana 44.
Postmaster
Joined: Dec 2002
Posts: 3,959
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From: USA
The rear end should be either a Dana 60 or a Ford Sterling 10.25". I don't remember what year they changed from the Dana axle to the Sterling. If it were my truck, I would change the front axle to 3.73 to match the rear. Since you are running slightly larger tires and it is a 4x4, and possibly you are towing or hauling something heavy sometimes, the lower gears will help with pulling and hillclimbing power and 3.73 is not so low as to rev out the motor too fast at highway speeds. 3.54 is still acceptable since you do have a big block but probably wont give you any better gas mileage except when running empty at speed on the freeway. That was what I found when I went from 3.55 to 4.56 in my F350 with 351 and C6. Try www.precisiongear.com or www.reiderracing.com for gears for your Dana 50 axle.
Senior User
Joined: Jan 2004
Posts: 153
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From: Harrison County, Texas, C
I am pretty sure that they first started using the 10.25 in 1985 so your rear should be a D60. A d44 in the rear of a 250 would be awfully lightweight for your truck. Unless It is some weird custom job it should be a 60
I would change the D50 TTB over to 3.73. I might be wrong but I believe the d50 ttb's use the same size RP gears as the d44 ttb's. Ask a dealer to be sure though.
I would change the D50 TTB over to 3.73. I might be wrong but I believe the d50 ttb's use the same size RP gears as the d44 ttb's. Ask a dealer to be sure though.
