Synthetic gear lube / rear-end size

[65-f100]

Hey guys - need a little help. I've got a 96 K2500 Suburban. I want to switch to Amsoil in the front and rear diffs. Saw on the Amsoil site that the synthetic may attack RTV sealant and it lists which ones are compatible and which ones aren't. First question - what is the easiest way to determine what size diff I have? Second - has anyone had any problems with leaking after switching to synthetic? Thanks!

[Keith Richards]

The only question I can help you with is the diff size.To my knowledge,(if you have the 6.5 engine) the only diff is the 1 ton 14 bolt.It has the 10.5 inch ring gear.That is the only axle I have seen under 3/4 ton hd trucks and burbs.And it's the toughest axle you can get for that application.

[Dvldog 8793]

Howdy
I have been using Amsoil in the rear diff for about 60k miles. I just recently had a leaking seal that caused my brakes to lock up :mad: so now my whole rear axle is appart. I have a full float and the ends are factory sealed with silicon, can't tell you what type they used except that it is black. I had NO silicon leaks and all the old stuff that I cleaned off showed NO signs of degredation. Can't tell about the diff cover as I have a maghytech that uses an o-ring seal. The rear lube that I use is Amsoil 75-90 series 2000. Up here in the cold I KNOW it makes a difference in the winter :D
Hope this helps!
L8r

[65-f100]

Thanks for the info. What size diff would I have in front - the 8.25 or 9.25? I noticed I have a front axle seal seeping - how difficult is it to get the axles out? I can see where the axle unbolts from the flange and I know how to get it out of the hub. How does the axle stub come out of the trans? Does it just use a clip like most front-wheel drive axles?

Thanks!

[number two]

The 3/4 and 1 ton trucks use the larger front differential,I'm assuming the Suburban is the same. The driver's side axle stub just pops out like a front wheel drive car,with a spring clip on the axle. Then you can change the seal-very common problem. The right side differs from the 1/2 ton and the 3/4-1 ton diff. 1/2 ton models also have the clip like the other side,as well as a washer that likes to drop down when pulling out the axle. 3/4-1 ton models must remove the extension housing. There is a regular snap ring that must be removed to remove the axle and change the seal. Red anerobic sealer is used to seal the extension housing when reinstalling. I've tried doing axle seal jobs with the diff in the truck,but anymore I just remove it and do it on the floor. Don't worry about synthetic lube eating up silicone. Good Luck.

[MTTwister]

number two -
I have a beginning leaky right front seak on the PU. Once they go, is this a continual battle keeping seals in?

Going to farm the job out, should I have them do both sides - ( a little less shop time charge on a double, than 2 singles )?
- the drivers side is currently looking ok.

Thanks

[joed]

Seems to be a popular problem, as my left seal seems to be seeping now as well (although making it 110k is probably not too bad).

Probably a dumb question, but having never removed a FWD axle before, can you achieve enough clearance on the driver's side by just unbolting the cv at the diff. flange without removing the wheel hub portion?

Thanks. Joe.

[number two]

Gentlemen-Yes the seals can sometimes be an ongoing thing. I just serviced my truck today and found my right side seeping a little. It's been over four years,but only 20,000 miles since I changed it. I bought the seals from the dealer. Maybe I'll try another brand next time. I also remember that clip on the drivers side axle shaft was broken in half and I had to wait another day for a new clip.
MTTwister-if you were having the right side seal changed,I'd surely have the driver's side done as well. It's the easier of the two do,especially if they remove the diff housing. If they were changing the right side by removing the extension housing in the vehicle and leaving the diff in place,and your other side ins't leaking,you could roll the dice. Two theories here-if it isn't broke don't fix it-vs the seals have the same wear on each other so the other one's due as well.
Joed-yes,there is enough room to remove the 6 bolts holding the CV shaft to the axle flange-it's not that hard to hold them out of the way.

[Tony J.]

Originally posted by Keith Richards:
if you have the 6.5 engine) the only diff is the 1 ton 14 bolt.It has the 10.5 inch ring gear.Cool! I was going to ask the same question, as I'm doing the same thing to my 95 K3500. My question though is, there are 2 10.5 inch rear ends listed on Amsoil's site- Dana and not Dana. Dana holds 5.5 pints, NOT Dana holds 7.2. How do you tell the difference?

[Scooby]

I dont think GM used Dana axles in the rear on the newer trucks. The Dana axle will have the series # cast below the cover in the web where the axle tube goes into the pumpkin. Dana 70 would be the possibility ina 1 ton truck, but I dont think GM used them.

[number two]

I believe the 10 1/2" GM rear end has 14 bolts on the cover and the cover is 6 or 8 sided,rather distinct,and also has a circle of bolts in the front as the pinion shaft is removed from the front. Dana axle would have an oval pattern to the bolts.

[Polar Diesel]

I believe the 3/4 hd's use gm rears, and the 3500 SWR 4X4 use Dana. I'm not sure about the duallys

[Dvldog 8793]

Howdy
My '99 3500SRW has a 14 bolt GM, it now holds 4.5qts I'm not sure what it held with the stock cover. A Chiltons manual should be able to tell you. ;)
L8r
Conley

[Polar Diesel]

They must have changed because I know that the early 90's 3500's used dana if they were 4X4, this was on regular cab trucks.