question for the diff experts
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Posting Guru
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question for the diff experts
my son bought two diffs for his 1977 f-150 there suppose to be 410's the rear diff is 37 crown 9 pinion=4.1111111 the front is 45 crown 11 pinion=4.090909 does it matter that there not exactly the same? we were also wondering if we put the rear assembly in,and pull the axles do we need to put new seals in, there not leaking at the moment. If it needs new seals, do the bearings have to be pressed off then on to get the seals done? or is it something we can do our selfs? the front seal on the diff is leaking, I assume the yoak has to come off to change the seal? sorry for so many questions, I guess while I'm at it how do we tell if it is posi or limited slip, I do know its one or the other
Posting Guru
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From: Dededo, Guam
question for the diff experts
I am assuming your son's truck is 4x4. The ratio's need not be exactly perfect. They can be within 1% of each other. 4.09 and 4.11 are close enough to work i believe. As far as the seals go if they are bad change them. I only worked on my 8.8 axle shaft seal so my expierience is very limited on changing seals. Posi's and limited slips are the same thing. Limited slip is just the broad term for it. GM called thier limited slip's(LS) posi-trac. Ford called thier LS, Trac-loc. Hope this helps you.
Posting Guru
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From: Copley, OH
question for the diff experts
Those are the correct ratios. Ford usually runs a hair less reduction in the front axle. Allegedly this gives greater stability in the dirt.
If you've got it apart CHANGE THE SEALS. They're like $2-3 each.
Your shop manual should have good illustrations of both open and limited slip carriers, they're easily distinguished once you've seen the pix.
If you've got it apart CHANGE THE SEALS. They're like $2-3 each.
Your shop manual should have good illustrations of both open and limited slip carriers, they're easily distinguished once you've seen the pix.
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question for the diff experts
Havng a higher ratio makes the truck turn a lot easier and pulls the front end around rather than the back end pushing harder. 4WD farm tractors have te same feature to enable sharp turns in loose dirt.
Post Fiend
Joined: Jun 2003
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From: NE Texas
question for the diff experts
Originally posted by omni
do you know if i have to get a machine shop to take the bearings off the axles, in order to change the axle seals,
do you know if i have to get a machine shop to take the bearings off the axles, in order to change the axle seals,
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Posting Guru
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question for the diff experts
thanks Big Orn, do you think I can change the pinion seal myself, I thought the pinion nut was tightened a certain amount to crush the crush sleeve, can you just take that nut off and reinstall it after you change the seal???
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Post Fiend
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From: NE Texas
question for the diff experts
No, just remove the yoke and replace the seal. Be sure to torque it back to specs - which I don't know right now - but there should be no problem with the shims just replacing a seal.
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Post Fiend
Joined: Jun 2003
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From: NE Texas
question for the diff experts
Originally posted by Big Orn
No, just remove the yoke and replace the seal. Be sure to torque it back to specs - which I don't know right now - but there should be no problem with the shims just replacing a seal.
No, just remove the yoke and replace the seal. Be sure to torque it back to specs - which I don't know right now - but there should be no problem with the shims just replacing a seal.
Posting Guru
Joined: Dec 1999
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From: Copley, OH
question for the diff experts
And use a new crush sleeve. They cannot be reused without risking damage to your pinion setup. If you reuse the same pinion and bearings, the shims will be the same. Make VERY sure that you keep the side shims on the carrier on the correct sides.
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question for the diff experts
For the pinion seal vs crush sleeve, check your shop manual. I changed (just) the pinion seal on a Ranger 7.5". The shop manual said it was OK to do that. I think the procedure involved measuring what torque it took to loosen the pinion nut - and then using that torque for reassembly.
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