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Rear Diff Seal ???

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Old May 17, 2016 | 12:55 PM
  #1  
Wrecklesswisdom's Avatar
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Rear Diff Seal ???

Hey guys, so im tryign to get a new seal for my rear diff as it has been leaking since i got it (very slowly, luckily all the mud keeps it pretty well sealed). The thing is, im not familiar with how to change this out. Most rear diffs ive dealt with have the seal facing the rear of the vehicle, this one the seal faces the front. Is this a special seal? Anything i should know before i start tearing it down?
 
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Old May 17, 2016 | 01:04 PM
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Are you referring to the diff cover gasket? If so I've been very pleased with the LubeLocker brand of gaskets. Lube Locker - Lube Locker
 
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Old May 17, 2016 | 01:21 PM
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Sounds like you are referring to the Ford 9" which is a whole other monster?
 
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Old May 17, 2016 | 02:19 PM
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its looks like this one. I thought i had a photo on my phone but i do not.

 
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Old May 17, 2016 | 02:22 PM
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That's a 9". A lot more involved than just un-bolting the cover. Gotta pull the wheels, drums, axles, and driveshaft. Then the center drop out weighs about 70lbs.
 
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Old May 17, 2016 | 02:26 PM
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Originally Posted by 351Cleveland C4
That's a 9". A lot more involved than just un-bolting the cover. Gotta pull the wheels, drums, axles, and driveshaft. Then the center drop out weighs about 70lbs.
All that just to change the seal? i cant just undo the driveshaft and drop the rear end?
 
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Old May 17, 2016 | 02:59 PM
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Originally Posted by Wrecklesswisdom
All that just to change the seal? i cant just undo the driveshaft and drop the rear end?
Nope.

The axles don't have to be completely removed -only withdrawn like 8 to 12 inches.

I can change that gasket in less than an hour.... It apparently takes 351Cleveland about five hours.

I'd rather have removable carrier than a rear axle where the gears have to be set-up inside the axle. .. and that's why NASCAR racecars use the Ford 9-inch design. Those guys can change a gear carrier between 10 and 15 minutes.

.
 
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Old May 17, 2016 | 03:02 PM
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Originally Posted by HIO Silver
Nope.

The axles don't have to be completely removed -only withdrawn like 8 to 12 inches.

I can change that gasket in less than an hour.... It apparently takes 351Cleveland about five hours.

I'd rather have removable carrier than a rear axle where the gears have to be set-up inside the axle. .. and that's why NASCAR racecars use the Ford 9-inch design. Those guys can change a gear carrier between 10 and 15 minutes.

.
Hahaha. I've done it pretty quickly, but about the time you think a job will be quick and easy, is exactly when it won't be.
 
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Old May 17, 2016 | 03:09 PM
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Originally Posted by 351Cleveland C4
Hahaha. I've done it pretty quickly, but about the time you think a job will be quick and easy, is exactly when it won't be.
"..sperience!"
 
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Old May 17, 2016 | 03:10 PM
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Originally Posted by 351Cleveland C4
Hahaha. I've done it pretty quickly, but about the time you think a job will be quick and easy, is exactly when it won't be.
beings i havnt done one of these before, i imagine ill be moving pretty slow and careful, but if i have to do all that i might just overhaul the whole axle, thinking about getting some lower gears so i get better MPG/top speed. not planning on doing a ton of towing, at the same time ive always prefered over-axled under powered builds cuz they break less. decisions.
 
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Old May 17, 2016 | 04:23 PM
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If you don't like your mileage now, going to lower rear end gears will definitely result in you liking it even less.

A numerically low ratio number is a high gear. A numerically high ratio number is a low gear.

2.75:1 would be a high gear ratio. 4.11:1 would be a low ratio.

--I also recognize the photo of the rear end you posted. That was the original 9-inch 3rd member with a 28-spline, single track differential and 3.50 gears that came in my '69 F100. I replaced it with a 9-inch N-case 3rd member with a 31-spline, 4-pinion, Traction-Lok differential with 3.50 gears. The Ford 9-inch N-case 3rd member came out of a '75 F150 4x4. The 31-spline axles came out of a '71 F100 that had a Ford 9-3/8" rear end.

Before the 3rd member and rear axle (28 to 31-spline) change in my truck.



During.



After the 3rd member and axles were swapped.

 
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Old May 17, 2016 | 04:33 PM
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If your just cruising around not doing any towing or hot rodding, a 2.75 is what I would recommend.
 
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Old May 17, 2016 | 05:14 PM
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Originally Posted by 351Cleveland C4
If your just cruising around not doing any towing or hot rodding, a 2.75 is what I would recommend.
....I have an '81 Bullnose 9-inch rear end assembly that has a stock set of 2.47:1 gears in it. If you had about 5 miles of straight road, could probably get the truck up to about 140.
 
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Old May 17, 2016 | 05:26 PM
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Originally Posted by Wrecklesswisdom
Hey guys, so im trying to get a new seal for my rear diff as it has been leaking since i got it (very slowly, luckily all the mud keeps it pretty well sealed).
Members are giving you instructions, but you haven't said which seal it is. Member in post #2 suggested housing gasket...which is not a seal.

Pic: The pinion seal is 4676 .. the axle seals are 1177 .. the housing gasket is 4035
 
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Old May 17, 2016 | 05:40 PM
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Originally Posted by NumberDummy
Members are giving you instructions, but you haven't said which seal it is. Member in post #2 suggested housing gasket...which is not a seal.

Pic: The pinion seal is 4676 .. the axle seals are 1177 .. the housing gasket is 4035
Thank you, its the housing gasket that is leaking, everything else seems to be dry.
 
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