Hi,

the rear diff seems to be leaking from the gasket on the cover. So I`ll take off the covers on the front and rear diff to change the fluid and put new gaskets on. But what oil would you recommend?

My personal preferences are Amsoil or Redline synthetics. Use some spray brake cleaner to get everything nice and clean inside the "punkin'", and inspect the gears for any chipped or broke teeth. New gaskets not entirely necessary, most folks just use the black RTV silicone high temp sealant, just favor the outer edge of the cover when putting the RTV on.
This is just MHO, others may have other considerations....

Hi,

the rear diff seems to be leaking from the gasket on the cover. So I`ll take off the covers on the front and rear diff to change the fluid and put new gaskets on. But what oil would you recommend?

Anything synthetic. I have always had good luck with Mobil 1 75w90 gear lube but I am sure they are all decent.

AMSOIL and Mobil 1 get my vote.:)

I use the Fleet charge in the gallon jug, but I will switch to Mobil 75-90synthetic before I try to tow any thing.
I have all ways sealed my 10-bolt's up with RTV only and never had any problems.

AMSOIL and Mobil 1 get my vote.:)

Are any additives necessary for limited slip diffs?

Peyton

Are any additives necessary for limited slip diffs?

Peyton

Yes, you can get it at any auto parts store, the clerks usually don't know what you are talking about though. It usually comes in a small 7oz. tube rather than a bottle and is located close to where you'll find the gear oil.

Some synthetics can run without. Really varies among trucks, but it's just easier to add it as opposed to wait for the chatter, and then add it.

Thanks, so it`s some synthetic 75W90. The glove box sticker says it`s a locking diff, and someone told me that they are different from limited slipping ones. Would I need a special additive for that?

Unfortunately, it`s leaking from the front where the drive shaft goes in. What would it take to fix that? I guess I`d have to pull the whole diff apart to get the input shaft out and replace a seal there? I can`t do that myself since I`d mess things up when it comes to align the gears, or before that. But I`m not sure if I can trust a shop with that, either :/

Maybe I should keep checking and refilling as needed for a while ...

You dont need to tear it completely apart. Remove the driveshaft, then you'll see a large nut that fastens the yoke to the input shaft. If you have a way to get that nut off(that's the hard part, an air impact wrench is the way to go), you should be able to pry the seal off. Replace with the new part that typically has a "crush sleeve" on it. You need to refer to the manual on your particular diff. to get the torque specs to set pre load, etc. when you replace the yoke. I'm sure I've over simplified the proceedure somewhat, but thats the gist of it.

I was told that you don't need a crush sleeve for the diff yoke (my diff seal is leaking also.)

BTW, yachtcare...I'm in your neck of the woods at least twice a week for work. Del Prado, Veterans, College...all over the Cape. :)

The crush sleeve thing probably depends on the make/model of the diff. Not sure what Olee is working on. I had the one on my '68 replaced and watched the guy as he explained the process to me. Basically torqed the yoke back on to a certain spec, to set the "pre load" then backed it off a bit. Wasn't very expensive as I recall. The one on my '61 needs replaced also, got the part, it looks like a front oil seal on the engine. One of theese days I'll get round to doing that.

Zeitgeist, My shop is on Skyline, about 1/2 mile north of CC Pkwy. Drop me a PM here next time your coming up, maybe we can do lunch.