Axle gearing question...

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Doug F
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Axle gearing question...

Post by Doug F »

Hey all,

I am curious, why is my front axle a 3.55:1 (as is stamped into the axle tag) and the rear axle a 3.50:1? (it's all factory FORD)

Wouldn't this cause drivetrain problems?

My new truck is 3.55 front and rear... :hmm:

Thanks!
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Re: Axle gearing question...

Post by fordman »

not sure if it would be factory. but that is close enough to work.
cep62
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Re: Axle gearing question...

Post by cep62 »

Doug F wrote:(it's all factory FORD)
well actually the front is factory "Dana"
but thats not enough difference to matter.
On loose dirt or snow you'll never notice.
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Re: Axle gearing question...

Post by Wes »

it is common to see 2 different gear ratios. Normally there is only .01 difference. For example, Ford 9" is 4.10 and Dana 44 4.11, 2 different manufacturers. 3.50 and 3.55 more than I have noticed. You wouldn't notice that in loose/soft stuff.
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Re: Axle gearing question...

Post by averagef250 »

The front axle is typically geared faster than the rear. I think HP 44 gears were made in both 3.50 and 3.54 ratios to work with the 9 inch and dana ratios. I haven't had a HP 44 that old (they just came out in 66), but all the 70's coil sprung ones I've had were 3.50 or 4.09. 3.55 in the front with a 9 inch in the rear and factory tags on the axles is an unusual find.

If it were mine and I found some 3.50 gears I would change them. you do not want your rear end spinning faster than the front in snow or ice.
1970 F-250 4x4 original Willock swivel frame chassis '93 5.9 Cummins/Getrag/NP205/HP60/D70
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Doug F
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Re: Axle gearing question...

Post by Doug F »

Yup.. Factory front and rear tags! (Old and rusty as they are!)

I'd need the reverse ring and pinion in 3.50 then.
Doug F
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Re: Axle gearing question...

Post by Doug F »

New Question:

OK, after some good long research, I have decided to replace the whole front axle assy with a 1976 Dana 44 assy w/Disc brakes and a 3.50 ratio.

Anyway, steering now has me thinking...

I see in the tutorials/tech section on here that early tie-rod end studs are shorter than later model ends, is this also true with Dana knuckles? (I am thinking the tech thing I read is for 2wd, but I am not sure)

IF it is true, what can you recommend for steering linkage (I don't want to use the 76 linkage, too many parts and the steering box is set to the 67 direction.) I like the simplicity of the 67 set-up and am possibly looking into HD Off-Road linkage too that steers from the PS knuckle...
Doug F
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cep62
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Re: Axle gearing question...

Post by cep62 »

The "76-77 linkage was a y style that has some geometry issues, and a expensive pitman arm.
the "78-79 style is a better set up.
I cant remember if I used the stock pitman arm or not. :hmm: (I think stock)
I've since switched to a power unit.
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Re: Axle gearing question...

Post by Redcap »

3.50 and 3.55 are close enough. You won't notice it at all.
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