To Remove or not? The Rear Differential Cover

[chuntag95]

Well, I have read everything I can find, but still no straight answers. I know to go with synthetic and where the plugs are and what sizes they take. Do I need to remove the rear differential cover :confused: Or, will just draining throught bottom plug be fine? Thanks for your opinions and I really enjoy the forum.

Later,

[mdrag]

Chris,

I removed mine....and replaced it with the Mag-Hytec diff cover tongue.gif

IMHO I would not remove the diff cover for routine maintenance - just drain, clean the drain plug magnet, and refill. Mine was very clean inside, and I see little benefit from removing it.

If you decide to remove the diff cover, chances are you'll need a new gasket, or plan to use gasket sealer.

[ram/tx]

Chris...I'm with mdrag. I removed mine and it was just as clean and nothing was gained by doing it, it just cost me, because I had to go buy a new cover gasket. I should have just drained it though the plug in the bottom and filled it back up.

[NickLeinonen]

rtv silicone works good as a gasket. but with a drain plug, you don't need to pull the cover. [i have to with my 10 bolt rear :( messy job :( ]

[chuntag95]

Thanks for the consensus. Not remove it is :cool: That should make it easier and quicker. Between oil, transmission fluid and now the differentials, I could start my own oil disposal company. tongue.gif Thanks again. :D

[Diesel_Lawyer]

I changed my rear differential fluid this weekend. I broke down and bought 4 quarts of the GM synthetic stuff from GM parts direct. I used the part number in the owners manual. The new fluid smelled like grape juice but was golden in color. The bottle said something like "new grape scent."

The fluid I drained was purple and smelled like grape juice.

Anybody else notice that the new fluid was golden but the old fluid was purple but both smelled like grape juice?

By the way I did not remove the cover. The drain plug had a small ammount of what looked like silver putty on it.

[hoot]

Diesel_Lawyer,

You may have just uncovered the big mystery mustard oil that's in the front differntial!

[Diesel_Lawyer]

I used part number 12378261 for the rear diff. It smelled like grape juice but was not purple.

[mdrag]

I used the GM $ynthetic and it looked like any other gear lube (NOT purple)...but with the grape smell.

mdrag

[KenZ]

All grapes are not purple. Maybe you got the white grape version.

That silver putty I believe is wear metal that has collected on the magnet. Very fine particles. I really noticed it on my front differential drain plug

Ken

[Jelisfc]

Do the front gears turn all the time?

[mackey_62]

Probaby no need to pull cover.
Unless you just have to see what it looks like inside :D
If your worried about thorough drain, opinions differ on whether it's necessary, just let each side down (not same time :D )to drain axle tubes.

I know what you mean about disposal, used oil is building up fast with those 10qt. changes.

How many miles you got?? Might want to let front break in a little longer. Get a few hundred miles of 4WD time on it. Unless thats gonna be winter and your doing it in the driveway :(

[mackey_62]

Jelisfc,

No, When in 2WD, front driveshaft disengaged and solenoid disengages output shafts.

Also, If you don't want to pay GM price :eek:
I got Mobil 75w90 synth for about $5-6 / qt.
Sold just about anywhere.

[ 10-04-2002: Message edited by: mackey_62 ]</p>

[chuntag95]

mackey_62,

I have 15,300 on it now. I have only been in 4x4 for about 10 minutes. I missed hunting season last year :( I was going to change the front anyway and then change it again next spring/summer. It's hard to tell where one starts and the other begin's in Texas ;) I went ahead and bought the Amsoil Series 2000 75W-90 for the rear and the 80W-90 for the front. I got enought for a second change of the front come front change time. As far as the driveway, I have a buddy that has a heated and more importantly A/C controlled shop. If he doesn't have a Porsche or a woodworking project in it, I can use it anytime. :D

[Colorado Kid]

Unless something has changed from the previous generation the front diff gears do spin anytime the truck is in motion.

The front drive shaft does disconect at the transfer case, and there is a front axel disconnect, but it only disconnects the passenger side output...the driver side is still conected to wheel speed. Usually the driveshaft does not spin, so as a result the spider gears do spin and the passenger side output spins backwards as fast as the driver side is spinning forward (ring and pinion are stationary).

[hoot]

I don't believe the passenger side axles spin at all. Don't the spider gears just roll around on the PS side gear?

That part gets a bit confusing.

[Jelisfc]

The reason why I asked about the front axle is if nothing turns then I don't see the reason to switch to synthetic. I don't use it enough to make a difference. If it does turn then switching could be an advantage. Mostly because of added drag this winter.

chuntag95 (Chris) Why did you put 75/90 in the rear and 80/90 in the front? Why not 75/90 in both?

[ 10-04-2002: Message edited by: Jelisfc ]</p>

[chuntag95]

Jelisfc, I went with the 80-90 for the front because it was about half the cost of the Series 2000 75-90. That is also the weight that GM recommends. Since I plan to change it again in the spring after I use the 4x4 more and really break it in, I saved a few bucks. I still went synthetic because I am an engineer and just plan retentive that way. :D Overkill is my speciallity. ;) (Running sythetic saved my Pontiac engine once already when the thermostat stuck closed.) I have already purchased the 2 quarts I need for the spring change and have it sitting on the shelf. Never hurts to have a spare quart of whatever is where ever. I do alot of research on what is best or percieved to be the best. I look at all of the specs and make the final call. Analysis paralysis is my biggest problem sometime. :rolleyes: Again, an engineering side effect.

[chuntag95]

Okay, got both the front and rear changed. The rear was black and I had quite a few metal flakes on the magnet/plug and about 1/2 of a quart low, which is what I expected (Thanks to you guys/gals.) The front came out looking pretty dark at first and then turned into grey poupon. Again about 1/2 a quart low, but no big pieces on the magnet, just lots of metal dust. (Probably some effenciency engineer said to short every truck 1/2 quart and look at all the money they save on the high dollar synthetic. :mad: ) I went ahead and hit all 11 zerks while I was under there, and again thanks, cause I had only found 8 before searching. :rolleyes:

Okay, now the part I need help on. In the front diff fluid was a bunch of yellow flakes. It looked like paint chips. I thought maybe the gears were painted and the paint wore off or the casting release materials coming out. Has anyone seen this and should I be worried :confused:

I did jack up both sides to get fluid out of the axel tubes. Now, should I check level in a week or two, or can I go on my merry way until the next oil change? :confused:

Thanks for the knowledge I am sure to recieve. :D