heldrasil

The last time I took my vehicle in for service I was told that they were unable to remove the plug from the rear differential to check it's fluid. They had told me that the plug itself had been stripped. On top of this, I have now been told that my axel seals are starting to leak. I have already dropped over $1k in this vehicle this month alone and can not afford any more repairs at this point in time, so this brings me to my question:

I am sure I can find a way to remove the plug myself, but I am unsure as to what fluid actually should be placed inside the differential. I have looked all over the internet for this info and can not find it, I have called the dealership and their only answer is "I'm sure it's some combination of gear oil and another additive"....

So I hope that someone here can help me out in finding this information.

Sheppy

Just go to an auto parts store and look up the weight of rear end fluid to use. Lucas is the best in my opinion, no additives needed, just drop the old fluid and fill with Lucas Rear End Lube. Chevy did a cool thing with the TB, there is a plug/cap on top of the diff's pumpkin with a hose commin out of it, it works nice if u have the right tools and fills easily. On the stripped plug, I dont have any suggestions, but deffinately get a new one when u get the old one off.

rbarrios

OK. Finally changed the oil in my differential. I changed the ORIGINAL FACTORY OILMilieage is 111,837The manual calls forSAE 75W-90 Synthetic Axle lube GM part # 78261 or meeting GM spec 9986115.I created a thread on the appropriate fluid to use- and the confusion that GM SPEC causes. In the end- after viewing documents online- AMSOIL 75W-90 Severe Gear oil is a perfect replacement. People have said Mobil 1 is ok to use- but I emailed Mobil 1 and they said they did not meet the spec- and to procure the oil from dealer. So its up to you if you want Mobil 1. Dealer oil, or AMSOIL. (or other stuff of your choosing- hopefully its meets requirements).So the parts needed are shown in the picture + You will ALSO need a 3/8 extension, a 3/8 ratchet and a breaker bar (if youre weak like me).

I went ahead and removed the rear tire- for several purposes. To check its condition, to refille with air, to operate the lowering mechanism, and to clean the tire. It also gives you space to work on the rear end.
on my 03, I have a drain hole. shown here.
Here is the location of the refill holeNOTE!!!!!, before you drain the oil, use your 1/2 inch extension and ratchet to try to remove the refill hole. It does no good to drain, if you cant remove the refill hole. Be careful using the extension- try to hold it in place as tight as possible. the little ball bearing on the extension may keep the extension from fitting in the little square- if youre not careful youll round the edges of the square. I used the breaker bar to help me get leverage.
Once its drained out- you can refill.Since my rear end had 111,837 miles on it, I wanted to see what condition the gears were in. so using a 13mm socket I started to remove the bolts.You will need the 3/4 socket extension to clear the metal bar that partially blocks 1 bolt- OR use a wrench.heres my cover- and views of the insides....
I was a little surprissed when I removed the refill hole- as it started to spill oil thru here. the level was high enough.....I placed the drain pan and let it drain a bit.I then proceeded to remove the drain plug and let it drain out.
Once its drained out- you can refill.Since my rear end had 111,837 miles on it, I wanted to see what condition the gears were in. so using a 13mm socket I started to remove the bolts.You will need the 3/4 socket extension to clear the metal bar that partially blocks 1 bolt- OR use a wrench.heres my cover- and views of the insides....





I did not buy a gasket- as Id seen on here that the gasket was rubber and most likey reusable. (and hard to get at auto parts stores- and if they have it- its wrong- as per members on here).I cleaned the mounting surface

I then cleaned the cover

then I cleaned the gasket. still in very good shape
I then put everything back toghether again. I didtn use a torque wrench. I tighethened the bolts to about what they felt like when I removed them. they werent that tight (never had a leak). I put all bolts in and tightened them like on the tires. across from each other... once it was all back toghether again. it was time to refill.The contraption I Have in the picture I had to cut the hose to get the bottle upside down and get it to drain. it was a bit messy- and tedious.Learn from me- and use a hand pump. (I had one- but dad had cleaned it out with gas- and I didnt want to introduce gas into the amsoil). so do yourself a favor and buy a little pump. it will make it easier....2 quarts is all youll need. it brought the level to a bit below the fill hole.(not sure why it had more when I removed the fill hole 1st time).here is what settled on the bottom when I removed the oil. the black spots were not metal....... they were sort of like plastic. cause I could crumple it in my finger. Im not sure if they fell in when I was undoing the drain holes.you can see the super fine metal particles.
here it is all put back toghether again..... I went ahead and cleaned the cross bar- since some oil falls on it.
I was surprissed what I didnt find......I DID NOT find any large metal flakes. chunks etc....I found less fine metal particles than I thought Id find.Could be they were suspended in the oil. (magnet would have helped).But in close inspection the rear end gears looks exceptionally good to me.

rbarrios

I did this in November of last year. I had 111,XXX miles on the vehicle.
Im now at 131,000.

the original post was on trailvoy.com and a discussion about it.
there was also a post I created about the oil to use back there.
I did contact the likes of Mobil 1 and they emailed me back saying their product did not meet the GM specs.
Amsoil did. so thats what I went with.

Also- I think the newer TB DO NOT have a drain plug.... for those, you simply remove the covers bolts at the top and when youre getting to the botton.... oil starts coming out...

and the ratchet is 3/8 not 3/4.

rbarrios

http://forums.trailvoy.com/showthrea...nge&page=3

2004LTGUYANDGIRL

THE FLUID IN YOUR REAR DIFF IS 75W90

AT MY SHOP WE CHARGE 29.95 TO REPLACE IT AND IF THE PLUG IS ROUNDED OUT WE WILL REPLACE IT AND PUT TAMPER SEAL(YELLOW PAINT) ON THE NEW PLUG THEN IF YOU TAKE IT SOMEWHERE ELSE, AND THEY SAY "IT'S STRIPPED" YOU WILL KNOW THEY DID IT BECAUSE IT LEFT OUR SHOP WITH TAMPER SEAL AND A NEW PLUG

ALSO ITS BEST TO CHANGE YOUR REAR DIFF FLUID EVERY 30K MILES IF NOT YOU RISK HAVING A BLOW OUT AND THAT CAN COST $1,000