Differential and Transmission Service

[endeavor to persevere]

Originally Posted By: ctc
Sorry if this is a dumb question. Does the AWD use the G80 rear diff?


Look on the label in your glove box and check the RPO codes for G80. That will be the Eaton locking Diff.

Quadrasteers could be had with a G86, that was a real limited slip and required the additive, I don't believe the AWD came with that diff.

 

[RoGuE]

In my Haynes manual it gives a torque spec (47 ft lbs I believe) for the differential drain plug. Is this necessary or can i just snug it down the same as an oil pan drain plug?

And for the transmission drain bolt and the bolts for the pan itself, do I need to use a torque wrench for that? Someone suggested I just snug them up since the pan bolts are speced for 12 ft lbs.

Also, what should I use to clean out the inside of the transmission pan? Brake cleaner?

 

[mechanicx]

Originally Posted By: RoGuE
In my Haynes manual it gives a torque spec (47 ft lbs I believe) for the differential drain plug. Is this necessary or can i just snug it down the same as an oil pan drain plug?


47 lb ft is higher than a typical oil plug, but if you have a good feel for tightening bolts, snugging it like an oil plug is reasonable.

Quote:
And for the transmission drain bolt and the bolts for the pan itself, do I need to use a torque wrench for that? Someone suggested I just snug them up since the pan bolts are speced for 12 ft lbs.


Again, it would depend on how calibrate of wrenching hand you have, but here a torque wrench would be a good idea.

Quote:
Also, what should I use to clean out the inside of the transmission pan? Brake cleaner?


How I would do it is clean it in soapy water like simply Green, rinse it good and let dry. I don't like to let anything into a transmision besides ATF. Brake clean would probably be OK too though. Most shops use a parts cleaner bench.

 

[Kestas]

The drain plug is probably a pipe thread (tapered thread). For those plugs I clean the threads with a wire wheel and use teflon tape to make the next service easier. With teflon tape (or any other thread treatment) 47 ft-lbs would be too much torque.

 

[AzFireGuy79]

I dont think you will ever (ok rarely if ever) see any trans shop using a torque wrench to tighten pan bolts. Just use a 3/8 drive ratchet and palm it, making sure all bolts are snug moving around the perimeter several times.

DOnt sweat the torque on the diff plug. See how deep it is in the case and just make sure its snug. Unless it is leaking, GM DOES NOT endorse the use of sealants on the plug. If it is leaking you can use the GM Goodwrench PTFE sealant.

Oh and BrakeKleen is more than ok for cleaning out the trans pan. I usually hit the valve body (avoiding the electronics of course) if the trans has been neglected. The nice thing about BrakeKleen and why it's ok to use on a trans pan is that it does not leave any residue.

 

[mechtech2]

Changing the rear end oil buy just dumping it from the drain plug is WAY better than not changing it at all.

As always, make sure your FILL plug can come out first!

 

[RoGuE]

Thanks everyone. I feel much more confident about doing this.

Now lets talk fluids. I'm going to stop off tomorrow afternoon to pick it up. Is Dexron VI synthetic by nature? Will it be available in Wal-Mart? And the diff fluid, will one such as Mobil 1 75w-90 (or something better) be available at Wal-Mart or will I need to pick that up at a parts store?

 

[endeavor to persevere]

Originally Posted By: RoGuE
Thanks everyone. I feel much more confident about doing this.

Now lets talk fluids. I'm going to stop off tomorrow afternoon to pick it up. Is Dexron VI synthetic by nature? Will it be available in Wal-Mart? And the diff fluid, will one such as Mobil 1 75w-90 (or something better) be available at Wal-Mart or will I need to pick that up at a parts store?


Castrol Dexron V1 is semi synthetic and Valvoline V1 is full synthetic. Here, Autozone has castrol while Oreillys has the Valvoline.

You may have to go to an autoparts store to get the Mobil 1 75W90. My Wal-Mart never has a good supply of Mobil1 diff fluid.

 

[AzFireGuy79]

Many claim ST is a blend. Other fluids like Valvoline VI are group III. At the end of the day both meet the strict spec of Dexron VI so who knows if you will ever see a real world difference between the two. Highly unlikely.

The one thing you will notice is how big a hit your wallet takes. Last time I bought ST DEX VI it was $3.77 per quart. Had to get a few extra bottles for top off because wally world ran out of ST and paid almost $7 per quart for valvoline DEX VI!!!

Mobil 1 gear oil is no doubt good juice. I prefer RL and amsoil but Mobil 1 is readily available from most any autoparts store.

 

[RoGuE]

Are both the Supertech and the Valvoline GM approved fluids? The Valvoline is $6.59 per qt and the Supertech is $3.77 per qt. Just have to decide which to get by tomorrow morning.

And I read somewhere else on here thT Mobil 1 diff fluid has slip additive in it? Is this still okay to use in my Suburban (2wd).

 

[AzFireGuy79]

I know Valvoline is a licensed product and last time I checked I believe Supertech is as well. I could be wrong on the supertech as I dont have a bottle laying around.

The Mobil 1 Gear oil will be more than edequate in your suburban. No worries there. If its an open diff the slip additive will not harm a thing.

 

[defektes]

Valvoline syn is a great product.

if your going with dino valvoline though the NAPA house brand is relatively the same stuff and a bit cheaper most of the time.

If you use Supertech I would change it out more often.


Not sure if they are GM approved, most likely yes.

 

[mechanicx]

Yes Supertech is available in Dex VI for about 3.75 or so a bottle at Walmart, quite the deal. And since it's Dex VI it is approved. I saw it at walmart the other day but I've never seen much of it, just one bottle.

 

[RoGuE]

Came back a little while ago. Picked up everything I needed. I got the Valvoline Dexron VI. It was $6.39 a quart, plus a 10% or so AAA disocunt.

They didn't have any Mobil 1 75w-90 but they had Valvoline so I just got some of that. I'm sure it's pretty good as well.

 

[AzFireGuy79]

Valvoline makes a very good gear oil. Did you get the syn-power or regular 75w-90?

 

[RoGuE]

SynPower

 

[RoGuE]

I got the pan off but could never get the drain bolt off. I am wondering if I should do something about getting that drain bolt off if I ever do this again. Should I try spraying some penetrating oil on it and getting it off? I can get the socket to get a good grip on it with the pan off but I turn it.

 

[JustinH]

In my F150's I would buy the royal purple gear lube that already had the limited slip additive mixed in.

I changed it about every 40-50k miles, or any time the diff was submerged in water.

 

[RoGuE]

Transmission fluid is now flushed. Wow, what a pain that was to drop the pan. I lost about 1.5 quarts of fluid on the floor and ending up throwing my shirt out, lol.

Differential will get done next weekend. I certainly took my time to do this.

 

[AzFireGuy79]

Great job! Yeah it's messy when dealing with that poorly designed drain plug. The fittings on the cooler lines are pretty straight forward until you loose a clip and find out they cost $13 bucks!!!

Now its time for a new shirt and a cold one!