Gear oil?
 

So, i'm getting my 4.10 gears and 7.5 posi installed this friday and im a little confused...should i let the shop put in their gear oil during install, then after 500miles put in royal purple?

whats did you guys do? (anyone who has had gears installed)

That's what I did, ran a few hundred miles then changed it out just to check it and make sure everything was wearing okay.

What posi are you getting? The Eaton posi for the GT that I put in my car said not to use synthetic oil and to use a mineral based oil

Thanks for the help, and i just got the ford racing posi off of AM.com

i assume royal purple will be fine!!!?

Yeah Royal Purple would be fine with that setup.

They don't do it from the factory like that so I wouldn't worry about it. Install fluid and go.

Royal purple gear oil sucks. Look up the data sheets. Just use motorcraft or moble1 or something to your liking.