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Differential oil capacity

Printed From: The Ford Torino Page
Category: Model Specific Forum
Forum Name: General Automotive Technical Discussion
Forum Description: Technical Automotive discussion of anything not specific to mid-size Ford/Merc
Printed Date: 24-March-2023 at 3:19AM
Software Version: Web Wiz Forums 12.05 -

Topic: Differential oil capacity
Posted By: Dmarc28
Subject: Differential oil capacity
Date Posted: 20-May-2021 at 12:50PM
Hey guys, have a question regarding differential oil capacity. 
I am in the process of converting my ranchero to rear disc. I am putting a rear end off of a 79 continental back there. The 3rd member I have in a nodular one with no fill plug. 

Sooooo, I wanted to put a fill and drain plug in the actual differential housing. 
Paul at Cook's machine shop out in East LA, did the drain plug for me. Tried to sub out the fill plug work and recommend a place in garden Grove that had the capability to put a fill plug in the actual 3rd member, like most of them are. I've read it's 2-1/2 quarts depending on the type of housing

So I was thinking if anyone knew how much oil a big bearing differential housing used then I could have my friend place the fill plug on the housing for me so I could get it re assembled and put into my ride. 

Any help would be great guys, thanks a lot. 

Posted By: pete rad
Date Posted: 20-May-2021 at 3:12PM
The oil capacity for the lincoln mark 4 rear end differential is two and a half quarts. I do not know if the lincoln continental rear end differential is larger than the lincoln mark 4 or lincoln mark 5 rear end differential. And i do not know if the lincoln mark 5 rear differential had a larger oil capacity than the mark 4 rear differential. The oil fill plug is usually installed half an inch above the oil full line.

The ford 9 inch rear end differential also uses two and a half quarts of oil.

Posted By: Dmarc28
Date Posted: 20-May-2021 at 3:36PM
Thanks Pete, I appreciate you and your reply. 

Posted By: pete rad
Date Posted: 20-May-2021 at 4:11PM
Your welcome. I meant to say that the oil fill plug is usually installed half an inch above the oil full line with two and a half quarts of oil in the differential.

Even the full sized fords such as the Galaxies, LTD's and Marquis's from 1972 through 1976 that came with the 400 and 460 engines and the larger rear end differentials, used two and a half quarts of oil in the differentials.

Posted By: Big Bird
Date Posted: 21-May-2021 at 12:48PM
Get a picture of the correct location and match it. do not obsess about amount of lube, as the axle housing cavities are different from year to year or chassis to chassis. Lube needs to be deep enough to do it's job.

"What we do in full frontal view, is more honest than your cleaned-up mind."
1979 T-Bird
2005 F-150 STX RCSB 4.6, 3.55 LSD
How the Heck does a REGULAR CAB SHORTBED weigh over 5200 pounds?

Posted By: californiajohnny
Date Posted: 21-May-2021 at 6:03PM
what randy said!
 here's the location of the fill plug...

75 VEGA V6 5 SPD
70 CHEV C10 P/U

Posted By: handsofstone
Date Posted: 22-November-2021 at 12:18PM
   I will say that when I did a reseal on the 2.75 in my car shortly after I bought it, I only had about a quarter in there. When it started to leak out I stopped. Mistake on my part for sure but never had any problems with it. When the center was pulled to put the trac-lok in, no oil spilled out of the housing. I would never make that mistake again.

Posted By: Eliteman76
Date Posted: 06-January-2022 at 4:32PM
Side note: it also depends if you are running the ball bearing axle wheel bearings, or a Type 20 Timken roller bearing.
The reason that changes is if you are using the OEM factory roller bearings, they need axle tube seals put in the ends of the tubes before the axles get installed.

Now in the case of the heavy duty Type 20 tapered roller bearings, you actually want to run more gear oil to ensure the axle wheel bearings are getting lubed. Typically I've done 2.5 or 2.75 quarts on my 1972 small bearing 9" housing.
I will be installing my 1976 housing in the spring, with my '72 N case carrier and I will be filling to the fill port on the carrier. Because I am planning up upgrading axle shafts from stock and going to Type 20 bearings, I've seen 3-4 quarts of oil at times.

Clear as mud? ;)

Andrew:GTS.ORG admin, '72 Q code 5 speed Restomod
Pondering: #99Problems

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