My Bravada transfer case and axles require GM exclusive lubes per GM and they are about 4 times higher than what Wal Mart charges. The two specialty GM lubes are:
Automatic Transfer Case Fluid GM # 12378508

Front and Rear Axle fluid (SAE 80-W90) GM # 1052271.

Especially with the transfer case fluid, GM made a major change in it a few years ago to address chatter in turning wheels at very low speed. Royal Purple lists an equivalent to the GM fluid on their web-site. My question- does it have what the GM fluid has? My quick research directs me to think Royal Purple is a small company and they either have awesome engineers or they are very good at marketing (like the K40 line of automotive electronics in the 1980'* that were crap but sold like crazy because they marketed so good).

Any thoughts on Royal Purple? How can they beat the big engineer budgets of a Mobile or Castrol?

Royal Purple overall kicks butt in the lubrication industry.

Last week I was working on an Envoy with the mechanic buddy. In having to refill the front diff he looked up the correct lube and it called for either GM lube or Royal Purple which was a synthetic and still fairly pricey but much cheaper than the GM version.

i'd use it.

thanks Bill

Royal purple for gear oil is out of this world never used it myself but, I know in the SRT-4 all the 350+ HP guys use it in their transmissions

Enough said...lol

Royal Purple is good stuff. I myself use AMS Oil products or Lucas Oil.

The cool thing about royal purple engine oil is that when you pour it in it'* actualy purple. but when you start the car and check it, it turns that amber color. So im guessing a chemical change is happening with the heat and preasure in the enigne.

I use royal purple oil in the summer and the purple water wetter.

they say that u can fill a motor with Royal Purple then drain it and it still provides more than enough friction protection to run the motor for a long time.

AMS Oil you can do the same thing. We did it to a buddies racing engine before they accepted the AMS sponsorship. They wanted to be sure that when they raced if they had motor trouble it wasn't from the oil.