What's the difference in diffs?

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What's the difference in diffs?

Postby Tallboy » Thu Dec 28, 2006 6:30 pm

I was wondering what the difference in a High pinion and low pinion diff is? :?
What are the advantages of the HP and would installing a front dana 60 from a 78 or 79 just bolt right into a 72 with 44HP currently :?
72 F250 4x4 Ford GT Red.
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Postby 72hiboy4x4 » Thu Dec 28, 2006 7:36 pm

your '72 has a HP diff? its been changed out, right?
My 72 has a 44LP stock. what transfer case do you have? (married or divorced?)
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Postby averagef250 » Thu Dec 28, 2006 8:14 pm

The high pinion axle has the pinion above the centerline of the axle while low pinion is below it. Ford low pinion axles are all made with a 5 degree down pinion angle for a divorced t-case. Ford high pinion axles are made with a 5 degree raised pinion angle for a mated t-case.

If your '72 is stock height a HP60 front axle will have issues with the front driveline clearing exhaust and clutch linkage. The '76 and newer ford disc brake axles are also wider than all early axles. Your front tires will be 3/4" further out on each side than they were with the stock axle. Not a big deal with a lift and bigger tires, but stock bumpsides can look goofy.
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re: What's the difference in diffs?

Postby Doug Comer » Thu Dec 28, 2006 10:16 pm

I have a hp60under my truck and it sits on the stock springs. I did have issues with the long tube headers but never had issues with the clutch linkage. For what its worth if you have a hp44 under it now the hp60 is just a bolt in deal. Doug

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re: What's the difference in diffs?

Postby Tallboy » Fri Dec 29, 2006 12:02 pm

Well 72 I guess I'm wrong.... :? I was under the assumption that all early fords came with HP44's and a Dana 24 t-case...... divorced of course. So it looks like i have a LP44 front......

Now I know. Thanks guys :thup:
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Postby pat67shorty » Tue Jan 02, 2007 9:50 pm

High pinions have reverse cut gears that are on the strong side of the gear during forward operation.

The low pinion axles have standard gears that operate on the weak side while moving forward... like driving a around on a rear axle in reverse.
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Re: What's the difference in diffs?

Postby Doug Comer » Sun Apr 10, 2011 11:21 am

The 67-72 F100's had HP44's and the F250's had LP44's, just to clear up any confusion with this thread.
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