[CaptainB]

I just put my new Ford aluminum differential cover last night. It looks great, but, when I was filling it with oil, it only took about 2 and 3/4 quarts. I thought it was supposed to take about 3.3 quarts not counting the friction modifier.
I put in one 4 oz bottle of friction modifier--1 quart of Mobil 1 75/140 synthetic--2 or 3 oz's of friction modifier--1 quart of Mobil 1 75/140 synthetic--I only got about 3/4ths of the third bottle of oil in before it started running out of the fill whole. Does that sound right.
The truck was on level concrete in my garage.
I figured I would put 15 or 20 miles on it and re-check.
Anybody know if the 3.3 quarts is including the friction modifier? If it does then I would be about right, but, all the other posts I read make it sound like it is 3.3 quarts plus your modifier.
Buster

 

[Going_Going_Gone]

I thought I read a posting here from someone saying theirs took 3 and 3/4 quarts, so I bought 4 for the swap. When I installed the finned cover and filled mine, just under 3 quarts of Royal Purple synthetic topped it off. I bought the friction modifier from Ford when I got the cover, but when I test drove it, it didn't need any. I guess some synthetics already have a modifier additive in them and others dont.

 

[Toptech]

I should take close to four quarts. At least mine did.

 

[Lightningfast01]

M1 is already slippery stuff, I would only add slip agent if it chatters. I htink mine took about 3.5.