Front Diff and Transfer Case Oil Change Howto

Quick question does the front diff need limited slip additive as well? Any additives for the transfer case?

 

No additives for either. Just pick regular dino oil or synthetic and you're GTG on both

 

I added limited slip in the front and rear none in the transfer case. Went with full synthetic. 75/90

 

I didn't add any to front or rear. Depends on what year you have too.

 

FYI - don't be a dummy like me and skip over that line that says 10mm hex for the front diff. I got the rear and transfer case done and then laid under the truck dumbfounded for about 5 minutes because I didn't have a 10mm hex (however I had a 10mm allen wrench and a rubber mallet - so I got the job finished).

 

i just hit 16,000 miles and ordered Mobil 1 and a 24mm socket to change my diffs. i may go more than 16K on the synthetic but i definitely want to get the dyno out of there before 30K.

i'll change the transfer case oil while i'm doing the diffs. why not?

 

I need to do this.

 

So the consensus is that 80w-90 is fine for front differential and transfer case? I can get 2 gallons of conventional GL-5 80W-90 for $20

 

I used 80W-90 for front, trans and rear ^

 

sub'd

 

Thanks for posting. Really helped.

 

Did the gearbox and tcase today. After 60k, the original oil in the tcase still looked new. Also, a 15/16" socket seemed to fit slightly better than a 24mm socket on the drain/fill plugs.

 

"oil looks new" I've noticed that too. I wonder how often it is really necessary to change this ? Supposed 2 B every 30,000 but I just change the rear diff last time.

 

Looking new and working like new are 2 different things when it comes to oil . . . but my opinion is that if you don't wheel regularly, the front could go 60K between changes without much worry. That said, I will still do mine every 30K because I am OCD and enjoy wrenching.

 

You didn't say it but I guess the additives can get used up and the oil still look new. On a side note the first time I changed the rear diff it looked like gray milk and stunk - the front diff and T-case always look new. I'll probably change all of them next time.

 

I am sure the BobIsTheOilGuy site may have some information, or maybe some other site -- I am not the expert on this. Basically, oil breaks down over time regardless of whether it is getting dirty. So while it may look clean, its lubrication properties are probably not the same. Not sure what additives there might be in gear oil, but I suppose they could break down as well. 60K miles is usually about 4 years for most people, and I would hesitate to use a bottle I had sitting around in the garage for 4 years, so keeping it in my tcase and front diff would bug me.

Gear oil stinks. I can smell it for a week after I do a change.

Not sure if you use an oil with a friction modifier (for LSD), but that as well as just normal gear wear can make it look like gray milk.

 

I think water may help to make it gray too. I don't think I can handle 10 beers with out some time and food involved but I do have a brewery 5 min's from my house if U R in the area sometime.

 

Nice

 

I'd like to have a beer in your neck of the woods. I was in Maui once - would love to go back.

 

Well if u ever do have a beer down here, make sure it's heineken. Green bottles is all we drink down here. Lol.