Silverado Rear End Fluid

[jbux]

My 01 Silverado Z-71, 3:73 gears, is due its one time only rear-end fluid
change at 7500 miles. The service manual says to put 75W-90 synthetic fluid
GM Part #12378261 or an equivelant of GM Spec 9986115. I wouldn't have a
problem using this fluid if it weren't for the $26.78 a quart price tag, and
needing approx. 3 qts. I have looked at all the local auto parts and
performance parts stores for an equivelant meeting GM spec's, with no luck.
I have even e-mailed GM and 3 of the big oil companies for guidance. GM, of
course, could only recommend their fluid and a certified GM dealership to
change it. I have not heard from the oil companies. I would normally of
used mobil or castrol in a minute, but we recently bought a 5th wheel camper
and don't want to take a chance toasting the rear-end with some brand not
meeting GM spec's. Has anyone had a similar experience or can offer some
advise.
Thanks

[Dean Dardwin]

Use Mobil 1 75W-90 gear lube. Much better and much cheaper.

Dean

[98 Camaro]

Sythetic Gear oil is expensive regardless. This debate has been here a
number of times. I know of one person who received word from AMSoil and
Mobile. Mobile said they were not compatible, AMSoil said it would work,
but they would not guantee it or commit it to writing at that time.
--
--
98 Camaro

Money can't buy happiness, but it sure makes misery easier to live with.
"jbux" <jbu...@shreve.net> wrote in message
news:3c1a3f3b$1...@news.shreve.net...

[Joshua Phillips]

Referring to what "98 Camaro" posted I would closely read that back of
the bottle to see if it meets GM's standards, I can't imagine why Mobile
1 would not. Regardless I always buy my gear lube from the local
Peterbuilt dealer here in Cincinnati. They fill the bottle I provide and
they are much cheaper than any of the so called auto parts places (Auto
Zone comes to mind, ugh). The best part is their stuff complies with the
specs of the people supplying GM with the axles (Eaton and Dana).

I always ask who they (Peterbuilt of Cinci) get their oil from, then I
promptly forget making it necessary to ask once again. I'm reasonably
sure it's a name brand none the less I'm confident those axles see more
action than mine ever will.

[Houblues]

> My 01 Silverado Z-71, 3:73 gears, is due its one time only rear-end fluid
> change at 7500 miles. The service manual says to put 75W-90 synthetic
fluid
> GM Part #12378261 or an equivelant of GM Spec 9986115.

Here is some information I found through Google, supposedly from the Eaton
company and various oil companies regarding the Eaton locker in a Volvo.
Yes, obviously a Volvo is not a Chevy truck, but I am posting it because of
it's reference to the GM "spec", which shows in this material as a part
number, not a specification. The site referenced is
http://www.brickboard.com/FAQ/700-900/Driveline1.shtml

Automatic Locking Differential Lubricants. [Note from Michael Asmussen,
Torque Control Products Division of Eaton Corp.] We recommend the following
lubrications for our locking differentials:
1)Texaco 2276; Synthetic 75 W90; Gm Part # 9986115
2)Texaco 9622; Mineral based 80W90; GM Part # 9985290
3)Texaco 2080; Synthetic 75W140 (heavy duty applications); GM part # 9985991
Note - All of the above lubes are preblended with friction modifier. No
additional modifiers are necessary or recommended. As far as other lubes
are concerned, any standard GL 5 lube will work, but the units perform
optimally with the three listed above.

[Comment from Castrol:] Thank you for contacting Castrol regarding Syntec
75W-90 GL-5 gear oil in your Volvo differentials with an Eaton Automatic
Lock. You may use SYNTEC gear oil with full confidence.

[Comment from Mobil:] Mobil 1 Synthetic Gear Lubricant meets the GL-3, GL-4
and GL-5 API ratings. If the manufacturer requires the use of a GL-4 rated
lubricant ONLY, then you should not use Mobil 1 Synthetic Gear Lubricant.

[Houblues]

Here is another reference, this one a GM service bulletin update for cars
and trucks through 2001.
http://www.geocities.com/crackeregg/01-00-90-001A.html

What is important about this reference is the difference in wording
depending on the vehicle referenced. For some vehicles they do not
reference the SAE industry-standard product, and say use only the authentic
GM product, like this: "Axle Lubricant, use only GM P/N 1052271 (in Canada
use P/N 10950849). Do not add friction modifier."

However for most vehicles, including the one of the original poster, the
word is different, apparently allowing the SAE product by including it in
the reference, like this: SAE 75W-90 Synthetic Axle Lubricant, GM P/N
12378261 (in Canada use P/N 10953455) or equivalent meeting GM Specification
9986115.

[larry]

I had purchased the amsoil lubricant as a replacement and at the last
minute decided to use the chevy stuff and choke on the price.
I was told amsoil was compatible but could not secure this in writing on
a brochure
Mobil 1 e-mailed me that it was not compatible to the GM Spec.
Because of warranty considerations I went with the way overpriced Gm
stuff
will change out to amsoil probably at 50,000 miles
My dealer said to change at 3000 miles Does he know something I dont
like a high failure rate?
I paid 19.50 a quart instead of the 26.00 list. I have three dealers in
the area and told one Look Im going to be needing other fluids in the
future and am looking for a place to do business with where I will buy
all my parts if you will give me a price break
Hence he will make less per part but will get all my business This was
not where I bought my silverado

--
remove junkmail to reply 2001 Silverado 67 firebird Conv 59 Sears
Highlander

[Marshall Richards]

My 2002 2500HD with the locker is coming up on 5k and I will be having to
look for a fluid supply also. Sounds like you worked a good deal. I
contacted Eaton about an alternate fluid and never got a reply from them.
I suppose they are working together on this. To bad.
MR

"larry" <HDYM...@junkmailprodigy.net> wrote in message
news:3C1B914F...@junkmailprodigy.net...

[jbux]

I'm sure you checked it out but the 2500's and 3500's use a different lube
than the 1500's. I ended up going with the GM stuff. I kept getting reply's
from the oil companies saying they weren't compatable. I did hear from a
few posts that Texaco 2262 is compatable with the lube I would have used but
I would have had to order it since nobody in this area sells it. Make sure
and ask the dealership how much to add, the 1500 takes about 2 1/4 qts,
yours will take more. The service manual in your truck doen't list the
rear-end capacity. Good Luck..

"Marshall Richards" <mc...@combuy.com> wrote in message
news:9vi7dr$fejga$1...@ID-12687.news.dfncis.de...