Overfilling rear diff?!
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From: Central Alabama
Overfilling rear diff?!
I decided to have a local guy (general mechanic) that I trust change out my Spicer/Dana 80 rear diff pinion seal. Funny thing is, I did'nt notice it leaking until I drained and replaced the gear oil several months ago. Anyway, I pay the $103 and the mechanic and I get to talking. He retired from Daimler Chrysler as a master mechanic and he mentioned that pinion seals usually leak from either normal wear or overfilling the pumpkin. Of coarse, I ask how that is possible. He said that the correct full fill level is one inch below the fill hole. He said that if you fill the pumpkin until it runs out of the fill hole, thats too much! He also mentioned that there is a Ford Bulletin out that states this very same topic. He even showed me the old seal and it was in great condition, the rubber was still plyable with no signs of wear. He put in the new one anyway and checked for any signs of wear on the pinion shaft and yoke.
So, I guess my question is: Has anyone heard of this before? I've always been under the impression, you fill it until it runs out and cap it.
So, I guess my question is: Has anyone heard of this before? I've always been under the impression, you fill it until it runs out and cap it.
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From: Morgantown WV
Capacities
Front Axle Liters (Pints) 2.8 (5.9)
Ford Rear Axle Liters (Pints) 3.26 (7.0) a
Dana 80 Rear Axle (Conventional Differential) Liters (Pints) 4 0 (8.5)
Dana 80 Rear Axle (Trac-Lok) Liters (Pints) 3.8 (8)
Dana S135 Rear Axle Liters (Pints) 11.6 (24.5)
Friction Modifier 236.56 (8) ML (Ounces)
a Service refill capacities are determined by filling the axle to the bottom of the filler hole. On Trac-Lok axles always add friction modifier first
Front Axle Liters (Pints) 2.8 (5.9)
Ford Rear Axle Liters (Pints) 3.26 (7.0) a
Dana 80 Rear Axle (Conventional Differential) Liters (Pints) 4 0 (8.5)
Dana 80 Rear Axle (Trac-Lok) Liters (Pints) 3.8 (8)
Dana S135 Rear Axle Liters (Pints) 11.6 (24.5)
Friction Modifier 236.56 (8) ML (Ounces)
a Service refill capacities are determined by filling the axle to the bottom of the filler hole. On Trac-Lok axles always add friction modifier first
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Posting Guru
Joined: Aug 2005
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From: Central Alabama
Originally Posted by cdiddy
Have noticed my rear pinion seal leaking too. How hard or what is involved in replacing it. Is this somthing I could do or does it need to go to a shop?
https://www.ford-trucks.com/forums/5...ghlight=pinion
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Thats news to me as well. Ive always been filling them to the bottom of the filler hole. I never had leaks or anything.
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Posting Guru
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From: Central Alabama
Originally Posted by mech2161
Service refill capacities are determined by filling the axle to the bottom of the filler hole
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Post Fiend
Joined: Jun 2006
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From: Central, Al
Here it is from the factory service manual. mine is about due guess i'll just put in 8 pints and the modifier and see where the lever comes to. "Pints in ()"
Lubricant Fill Level Checks Axle Model Ford Specification Approximate Capacities
Liters Pint
80
(Conventional and Truetrac® Differentials) WSP-M2C197-A 4.0 (8.5)
80
(Trac-Lok®) WSP-M2C197-A 3.8 a (8.0) a
a) First fill the axle with 0.2365 liters (0.5 pints) of Additive Friction Modifier C8AZ-19B546-A or equivalent meeting Ford specification EST-M2C118-A
Lubricant Fill Level Checks Axle Model Ford Specification Approximate Capacities
Liters Pint
80
(Conventional and Truetrac® Differentials) WSP-M2C197-A 4.0 (8.5)
80
(Trac-Lok®) WSP-M2C197-A 3.8 a (8.0) a
a) First fill the axle with 0.2365 liters (0.5 pints) of Additive Friction Modifier C8AZ-19B546-A or equivalent meeting Ford specification EST-M2C118-A
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Posting Guru
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From: Central Alabama
According to every website I have found about differential filling, it says to fill until the fluid dribbles out of the fill hole.
There seems to be a lot contradictory information about what this mechanic has told me.
There seems to be a lot contradictory information about what this mechanic has told me.
Post Fiend
Joined: Oct 2003
Posts: 5,903
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From: MICHIGAN
A friend works a Tratech, Detroit Locker, he runs the axle dyno. He says fill till it runs out. The seal and/or bearing failures are most likely non-related, schmit happens! You can overfill a diff especially if you working on a hoist or with the axles sagging. They almost always sag lower on one side. The fill hole is above the bottom of the axle tube in most cases, allowing the fluid to fill the axle tube before it runs out of the hole. Hope that makes sense. Bottom line: Level the axle before adding fluid.
BTW: I'd like to see the Ford Bulletin/TSB
BTW: I'd like to see the Ford Bulletin/TSB
Last edited by Cuda_jim; Oct 7, 2006 at 06:53 AM.
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From: Central Alabama
I'm going to filler-up to the bottom of the fill hole and check the vent tube today. Upon reading some of those webpages lastnight, it mentioned that a blocked vent tube can create pressure in the pumpkin, resulting in a leakage. Thanks guys for your replies.