rear diff oil

[Night Shifter]

i finally bought a set of 3.73 for my car but i want to use the best gear lube. any suggestions? I'm looking at royal purple max gear 75w90. I'm a noob to the rear diff so how many bottles do i need?does it matter the year car you have for gear lube?

 

[Nightstick]

i finally bought a set of 3.73 for my car but i want to use the best gear lube. any suggestions? I'm looking at royal purple max gear 75w90. I'm a noob to the rear diff so how many bottles do i need?does it matter the year car you have for gear lube?

I run Mobil 1 75/140 without friction modifier. Need 3 quarts. Won't quite use all of it though.

 

[four six]

Year won't matter at all, because they are all the same since 87. 3 qts of Royal purple 75 or 90w

 

[Kilgore Trout]

Plain old 80W-90 gear oil will be fine but overspend if you want...

 

[lvmustanggt]

with my T/A rear end cover and 3.73 I use 2qt of Royal purple 75w140

 

[Kilgore Trout]

Prior to 2001 Ford spec'd 80W-90 gear oil, mid 2001 they started specifying 75W-140 synth. Should be a tag on the diff if there is any confusion.

Use 4 ounces of friction modifier regardless unless it is already "in there" like with Royal Purple.

 

[blackfang]

When I did the gears and TA Girdle I used M1 80w90 and Fords bottle of friction modifier.