Be been wanting to change my diff fluid but I'm not sure which kind to use. I've got Yukon 5.13 gears with the factory limited slip in the rear. I'm not sure if it makes a difference but I'm going to be doing a lot of heavy towing also. Thanks.

 

Pretty much anything GL5+ rated,, it will say so on the container.

 

for towing run 75w140

 

I run mobile 1 full synthetic gear oil - If you have an LSD, make sure you use the correct amount of friction modifier - running without any will destroy the gears.

 

You shouldn't run friction modifier with synthetic lube on an LSD. If the gears don't chatter, it isn't needed.

 

Screwing up my limited slip is my concern.

 

So can I use mobile 1 full synthetic and call it a day?

 

Add the amount to the diffs needed form the friction modifier for the LSD then too it off with the diff fluid that you choose. I would run Lucas then if you like mobile 1 use that for the fluid

 

I used the valvoline diff fluid with the limited slip friction additive in it. I heard from people it works great. I will prob change it before it's due just to see how it looks

 

That really depends on your LSD and its friction modifier requirements. If you use too much your LSD just won't do anything - if you use too little you'll destroy it.

Some synthetic lubes might not contain adequate friction modifier - it depends on the lube. I've seen a guy destroy a Jeep LSD using synthetic valvoline gear oil because the bottle said it was designed for use in LSD's - but it didn't contain enough friction modifier.

In my opinion - if I had an LSD, I would use the exact same stuff and friction modifier amount that the dealer uses and call it a day.. That's what it's been tested with. Anything else is a guessing game.