Replacing differential cover

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Aug 23, 2011 | 11:05 PM

fordtruck661

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Replacing differential cover

Hi guys Im looking at replacing the differential cover because it is rusted bad and looks to be leaking oil from the middle and bottom of the cover. just some of the questions i have are would you use a gasket or Permatex. Also Im thinking of just using 85W-140 oil for it seeing that its around $13 cheaper than the 75W-140. Any tips would be great.

Thanks

Aug 23, 2011 | 11:14 PM

snakedoc

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From: AL, Reform

i would get one from a 08+ there bigger and look good.
http://www.riffraffdiesel.com/catego...DIFF-FORD.html

Aug 24, 2011 | 07:05 AM

Ponyboychris

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From: Kiowa CO

Here's a good write-up. Welcome to guzzle's Rear Differential Maintenance Web Page

There's no gasket, just use some good permatex and I let it skin up for 20 minutes before putting the cover on then let it sit for 2 hours before adding fluid. No leaks. It's highly recommended to use synthetic oil (75w-140) and it was the most expensive part of the procedure but given the abuse the gear oil takes in the rear-end, I looked at it as necessary expense.

If you can swing it, get the '08 cover as well from Clay like Matt suggested. They are nice.

Aug 24, 2011 | 09:56 AM

rufushusky

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From: Walpole, MA

Quote:

Originally Posted by fordtruck661

Black RTV works very well, I highly recommend the 08 diff cover, I got it for like $60 bucks at a local ford medium duty shop, then 12 5/16-18x1.25 bolts and your good.

Also ford spec'd a 75w-140 synthetic for a reason, I would use it. Also check to see if you have a limited slip diff..if that is the case you may need to add friction modifier to the fluid. I didn't need to do that with my Redline gear oil but some other brands you might. Really the diffs can run 100-150k+ on a good fluid...I would just throw a synthetic in there and call it a day. Cheap fluid, expensive parts and long drain intervals are not a good mix. Also were are you looking for gear oil? You can usually find mobil 1 75w-140 for like 18 bucks a quart or Amsoil 75w-140 for 16 a quart.

Aug 24, 2011 | 10:05 AM

rufushusky

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From: Walpole, MA

I was just thinking you can usually get valvoline 75w-140 for like 12 bucks a quart at napa. Valvoline makes a pretty solid fluid in my opinion.

Aug 24, 2011 | 10:14 AM

fordtruck661

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Quote:

Originally Posted by Ponyboychris

There's no gasket, just use some good permatex and I let it skin up for 20 minutes before putting the cover on
If you can swing it, get the '08 cover as well from Clay like Matt suggested. They are nice.

When I looked online they were selling the covers with gaskets and for getting the 08 cover I wish i had the $$ for it but I just bought this truck and am short on cash.

Thanks everyone for the replies!