725Gus

Has anyone got any experience with using redline 75W90 oil in their diff?

I've got an 06 5.9L CTD with an 11.50 rear end. I was told by the dealer that I should have it changed and frankly when I got their price I almost EDIT a brick. I stand a better chance at doing it affordably myself and I've always trusted synthetics in my road and race cars so no harm done here on the truck I figure.

Or is there any reason that anyone can think of that I shouldn't?

Stovetop535

How many miles do you have on your truck? I would not waste your money on the dealer. It is extremely easy to do yourself. I personally have no experience with redline, but any name brand synthetic and you will be fine. I currently have valvoline in mine now.

725Gus

about 36k

All of them pulling about 10k behind it and this would be my first change.

Stovetop535

I would just spend a few hours in the driveway this weekend then. I have a friend with 175k on his truck and I dont know if he has ever changed his diff. fluid.

I change mine about every 30k.

1985cucv

yes do it yourself very easy i run ams oil in mine

TexasCTD

I have heard good stuff about Redline. Any GL-5 rated 75w90 gear oil is fine. I use Mobil 1 from VatoZone.

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725Gus

One last question for you boys.

Is there an actual gasket for the diff cover or is it true what I've been told that you just use a good RTV?

Also, what's the capacity?

TexasCTD

Should have a hard rubber reusable gasket. Just wipe it off and reinstall. No need for RTV.

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Stovetop535

Rear capacity is just under 4 quarts, and front is just under 3 if memory serves me.

Make sure you clean/brush all around the diff before you pop it off, otherwise dirt, sand, ext will fall into the gears once the cover is off.

725Gus

Thanks to all, I appreciate it.

92'1stGen

Last week when I went to the dealer, (because I still have free oil changes left), they brought me a list of prices for what things needed to be done to the truck. They listed changing both diffs, the air filter, and the fuel filter. They also mentioned that all of these, except the air filter, should be changed every 15k. Funny though, they never mentioned anything at 15k and I have 30.4k on the truck right now. Anyway, I already knew in my head that I wasn't going to get any of those things done at those prices. Plus I had already changed the diffs at 15k, the fuel filter has already been changed 3 times, and the air filter I was planning on changing.

But the moral of the story is, it's real simple in changing the diff fluid. Just be super careful not to over torque the bolts to the covers and snap one off in the housing. There about as tough as a stick of butter in an oven. Just snug them up and they'll be fine, that's what I did. Next time I change the fluid I want to replace the bolts with a tougher grade so I don't have to worry about this. Also, stovetop was correct in the amount of fluid need, 7 quarts should work fine.

Billy Ram

The gaskits will last many changes. Mines been changed 6 times and no leaks. Just snug the screws down enough to seal. They won't back out. As far as oil goes you can use any GL-5 80-90 W and I don't use synthetic. 15K is not long enough to justify expensive oils. Your seals will like the dino oil better anyway.
Billy

D45

Yep, and nicely made gasket.......feels like a steel internal ring, coated in rubber, like those nice Lube Locker gaskets