Rear diff fluid?

[Motorhead350]

I noticed mine is leaking. I'm going to change the gasket, but what kinda fluid does it need and how much should I buy? Stock diff with 4:10 Ford Racing gear.

Thanks!

EDIT: Used search found 75W-150.

Nevermind.

[Egon Spengler]

Search function is your friend.

[LeoVampire]

Get a lube locker 8.8 10 bolt gasket $15.00 to $21.00? and the cover will not leak again unless your stock cover is distorted.

Get a rag and drag out all of the old fluid out of the bottom of the diff you will feel a deep gully in there as your pulling the rag out this was here most of the fluid will be changed out except what you can't get at on the gears and in the outer axle tubes.

Fill it till fluid is comming out the magnetic fill plug hole then cap it off.

As to gear oil just make sure you use some Ford Friction modifier during the fill. I used 2 of these but I put in the larger TA cover.

A lot of people will chime in on what they think is the best gear oil so I will leave that one alone.

[ctrlraven]

2.5 to 3 quarts of 75w-140 Royal Purple or Motorcraft with a 4 oz. bottle of friction modifier.

[justbob]

2 quarts Motorcraft synthetic 75 - 140 and two 4oz friction modifier FTW. Not a single chatter and great hook up.

[Motorhead350]

Would 80W-90 work? It seems to be a lot less and what came in the car originally.

[fastblackmerc]

Would 80W-90 work? It seems to be a lot less and what came in the car originally.

80w-90 was the original spec. fluid, but Ford changed to 75w-140. IMHO, I'd go with Redline, no friction modifier needed. Been running that for over 50k.

[Blackened300a]

I sue Royal purple. It has the friction modifier in it and its been working great.

[tbone]

Search function is your friend.

Search function sucks.:flamer:

[Blackened300a]

Search function sucks.:flamer:

Yeah, its jammed up with stupid polls and nonsense. You have a better shot of getting a Marauder engine related question answer from google.

[RF Overlord]

^^^what fastblackmerc said^^^

Dom, with your power level (and the way you drive...:D ), I would recommend you stick with synthetic 75W-140. That's what Ford put in the CVPI and what they include in the axle TSB kit.

As mentioned above, Motorcraft, RP, and RedLine are all good choices, but another alternative is Valvoline (available at any NAPA). Their version of synth 75W-140 has the friction modifier built in as well. I just bought some for Phoebe to replace the 80W-90 conventional I put in for a quick flush after the axle replacement. It's going in this weekend.

[tbone]

Yeah, its jammed up with stupid polls and nonsense. You have a better shot of getting a Marauder engine related question answer from google.

+1 bazillion!

[Black_Out]

You don't have to use the additional friction modifier with royal purple right?