Rear Differential SOAKED In Oil

1959 - 1978, M151, M151A1, M151A2, Technical questions and discussions, regarding anything related to the M151.
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Crux444
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Rear Differential SOAKED In Oil

Post by Crux444 » Tue Jun 01, 2021 2:05 pm

So this isn’t good - my rear diff is soaked in oil and has coated the swing arms, propeller shafts and underside of the rear tub. I’m thinking that clearly one of the seals has gone - probably P/N 12259428.

I think I will have to pull the diff and replace all of the seals to be sure. Before I do:

A) Could it be anything else? The main gasket <GULP!>?
B) Can I just replace the seals, or do I have to do a full teardown?
Canadian Army (1988-2011)
Kandahar, Afghanistan 2006-2007

M151A2 CDN (1974)


Rickf
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Re: Rear Differential SOAKED In Oil

Post by Rickf » Wed Jun 02, 2021 5:41 am

It will be one of the seals, normal for these. Get a seal kit which will include wear sleeves and install the kit. Just so you know you will expand your four letter vocabulary trying to get those old seals out. They are substantially longer (deeper) than civilian seals. Be careful you don't score the housing in the process. I am mentioning this since we see a lot of people asking HOW DO I GET THIS OUT!!!!!!!. You just need to keep working at it and it will be pretty much destroyed by the time it comes out so don't try to finesse it. Taking the diff out and doing it on the bench will make the job easier as long as you have a way to secure the diff so you aren't chasing it all over the bench.
1964 M151A1
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone

svramselaar
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Re: Rear Differential SOAKED In Oil

Post by svramselaar » Wed Jun 02, 2021 9:34 am

Hi
On top off the diff. Is a ventvalve
If this is clogged the pressure inside go up
1976 ? M 151 A2 AMG MUTT lost in acsedent
1978 M 416 A1 ( parkhurst ) trailer
1970 m151 A2 FORD BUDD tub
1957 Volvo sugga radio truck
M 274 mule HOME MADE MULE

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W. Winget
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Re: Rear Differential SOAKED In Oil

Post by W. Winget » Wed Jun 02, 2021 10:28 am

Order seal kit, pressure wash it, re-fill, drive around and look for the fresh leak, (clean vent as suggested) then if it still leaks, attack it...

or

go with a thicker gear oil. Now that's debatable, but a thicker Mobil "6" Gear Oil (I think it's called that) I'm currently using in my Ford Mower Deck gearbox and front spindles of the GPW. it wouldn't leak out and is made for industrial gearboxes and differentials. Science has advanced.
V/R W. Winget
Looking for 1918 Standard B 'Liberty' truck parts

Rickf
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Re: Rear Differential SOAKED In Oil

Post by Rickf » Wed Jun 02, 2021 1:19 pm

Keep in mind that you need an oil that is fluid so that is is in constant flowing contact with the case for cooling. I think what you are talking about is an updated version of corn head grease. Not so sure that is up to the job if you are driving down the roads for any distance.
1964 M151A1
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone

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W. Winget
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Re: Rear Differential SOAKED In Oil

Post by W. Winget » Wed Jun 02, 2021 2:29 pm

Mobil Gear 600XP 460 Gear Oil
Made for heat too.
Just a thought.
Waw
Looking for 1918 Standard B 'Liberty' truck parts

Rickf
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Re: Rear Differential SOAKED In Oil

Post by Rickf » Wed Jun 02, 2021 3:12 pm

I say fix the seals and use regular gear oil in it. I have never seen one with worn bearings due to bad oil unless it was full of water. Usually they go bad due to lack of oil because it all ran out. As one of mine did when the seal went out catastrophically. I drove about 25 miles with no oil in the diff. She was glowing when I got home!!!! Surprisingly nothing seized or welded itself up. When I tore it down it was rough but the bearings were still all in one piece.
1964 M151A1
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone


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