What axle do I have?

[bizzo15]

I know it's a coporate 10 bolt with the 3.42 gear ratio but what size is it 8 1/2 9 1/2 or 10"? I'm getting ready to pull the cover and refill the fluid. What kind of gear oil does it take 80w90?

 

[Greg]

i think its 8.5"

and yes 80/90 will work.

 

[bizzo15]

Thanks greg, is there any better weight i should be using? I thought I read somewhere that if you're gonna tow use 75w140 or something like that and I'm assuming synthetic would be preferred.

 

[Greg]

I use 80w90 in my rear end, and 5w30 in my engine and i never use synthetic. that is just how i was taught to do it and that is how i will always do it.

 

[bizzo15]

I can understand not using synthetic in the motor especially if you haven't done so since it was new due to leaks and what not, but I think it would be beneficial in a differential. I'll probably stick with regular though just because synthetic diff lube is twice the price of the regular stuff. You run 5w30? I was thinking these v8's would take 10w30 and that's what I bought for my first oil change. Doubt it will make a big difference either way though.

 

[tattooed4life]

Run 5w30 just like it calls for. I changed my diff. fluid and put the Lucas synthetic in it. IMO that's the only way to go.

 

[Greg]

I rock the Quaker State High Mileage 5w30. I love the stuff.

Takes one 5 quart jug to fill the motor up, and around here that one jug is about $12, where as each quart is around $3+

 

[bizzo15]

Well I changed out the rear diff fluid. Good thing I did too, what a nasty mess, looked like chocolate milk in there. One of the bolt holes was stripped on the bottom of the diff so I had to hunt around and finally I found a sel threading bolt that did the trick. Otherwise it would have been a breeze to change out the fluid. Did discover though that I have an axle seal leak as my driver's side rear brakes are soak in diff fluid. How hard of a job is it to replace those on these chevy trucks?

 

[Aloicious]

axle seals aren't too hard to change, you need to pull the tire, pull the brake drum, remove the differential cover, get into the carrier and push the axle shaft in to allow removal of the C clip (there should be an access point somewhere on the carrier, different carriers are different on how they are set up though, I'm use to my detroit which is different that a GM carrier so I can't remember how GM does it, I think there is a cross shaft bolt that needs to be taken out before you can get to the C clips.)....then once the C clip is out, carefully pull the axle shaft out, pull the old axle seal, and tap a new one in, then reverse the process to re-assemble everything. its really not too bad.

as far as fluid goes, I usually run either 75w-90 or 80w-90. I prefer synthetic everywhere. there used to be a time when synth could cause leaks due to higher detergent amounts, but that was back 30 years ago, synthetic oil technology has come along alot. switching to synth shouldn't cause any issues whatsoever. and it has higher sheer strength and breakdown resistance (among other things) than conventional. however it does cost more, so if you can't justify the cost, there's nothing wrong with conventional. whatever you do though, get a quality brand. I prefer either M1 or RP for the gear oil...in fact I make my own concoction for the rear end, I mix some ultra fine molybdenum disulfide in with the gear oil to help further reduce friction and the subsequent heat in there. works great.

 

[bizzo15]

Okay seems easy enough, I wonder if anayone has the torque specs for the cross shaft bolt and c clips? My alldata supscription doesn't even list the axle seal replacement procedure which ****** me off since I spent $30 for the subscription and it doesn't seem to have half the repair procedures listed for this truck.