[JohnnyO]

This is the gear oil that GM recommends for the rear axle. The famous "grape juice"


Not sure if this makes it any better than any other synthetic? But so far no oil company lists that they conform to the GM spec.


Found this on another forum:


“Heavy Duty SAE 75-90 extreme pressure GL-5 axle lubricant, new grape sent”
code:
<HR>




<BLOCKQUOTE>Contains:
Hydrogenated trimer and tetramer of decene CAS #68649-12-7
Propene, 2-methyl-, polymers- CAS #9003-27-4
Mineral oil, Petroleum distillates, solvent refined (severe) - CAS #64741-97-5
Amines, C12-14-tert-alkyl, reaction products with 0.0-di-C1- Cas #71888-91-0</PRE>
<HR>
</BLOCKQUOTE>


Explaination of Ingredients:


Hydrogenated trimer and tetramer of decene CAS #68649-12-7
[This is a mixture of PAO base oils]

Propene, 2-methyl-, polymers- CAS #9003-27-4
[This is VII and Friction Modifier]

Mineral oil, Petroleum distillates, solvent refined (severe) - CAS #64741-97-5
[Heavy mineral oil or brightstock to thicken oil]

Amines, C12-14-tert-alkyl, reaction products with 0.0-di-C1- Cas #71888-91-0
[Surfactant, Antioxidant and friction modifiers].

They do not state the EP additives since this info is proprietary.
Edited by: JohnnyO

 

[JimWilson]

I called Mobil and they said there synthetic ATF and gear fluid is fully compatible with GM's specs.

 

[1822]

My GMC dealer uses Mobil Syn. gear lube. Can see the drums in the shop. Interesting note is it is not Mobil 1 gear lube. Maybe it is just the packaging.

 

[peachin]

Of course, those who are towing are using 75W140 grape juice. Arn't you?

 

[JohnnyO]

I was stuck on whether to go to the higher viscosity. I tow a travel trailer regularly throughout the summer. I was thinking of putting the 75W140 in but it really doesn't get that hot here like in Texas and our winters are pretty cold.


The GM stuff is too expensive to switch grades between summer and winter so I just stuck with the 75W90.


What anybody's thoughts?Edited by: JohnnyO

 

[peachin]

I changed my rear end fluid after the first 500 miles of towing which was at 1000 miles and went to 75W140 I really will not have to change it for awhile. 75W140 will always be better than 75W90 as it has that and more. I have towed in 90 degree weather most of the summer. I now have 15,000 miles of which 12,000 are towing 19000cgvw. My major concern these days is clean fuel and if you have to pay to change the fuel filter - watch out the dealer will charge over $80. I will be changing it every 8,000 miles. However I am now cinsidering the CAT pre fuel filter - The money for all these add-ons keeps going out. But the Juice was worth it, the guages were worth it and the 4" flow thru muffler is worth it. I guess it all has to do with how long you (we) plan on keeping our D/A's - It's a towing pleasure while driving a Cadillac - (and at the same time a complex computer on wheels) Of course the Allison is just one amazing piece of equipment!


But just like one tight, hot looking woman with lots of Chrome

- she requires lots of maintenance to be happy - sucker!