There are a few online places you can buy this GM product.
But considering that you only need to change it infrequently, just get the GM Part No. U.S. 89021806.
Don't look for deal on this stuff.

 

This GM top secret fluid has been out for 10years.. Nothing special, just a synthetic oil with additives. The recipe has been copied and most likely improved. Pennzoil and Valvoline have the compatible fluid, much cheaper. Changing the fluid at recommended intervals is the key!

 

This is correct info - proper maintenance intervals.
But the manual states that the fluid doesn't need changing. (ever)
This is not a policy I follow. I just don't want CarlosC to go out and get any ole manual tarns gear oil, in attempts to save some bucks. This GM stuff is just not that expensive.

 

I hope he does some research or use 1 of the products I previously posted that is compatible. I did research and the gm special recipe is basically a syn 10w40 with additives.

__________Proper maintenance==== preventative maintenance===prevent premature failure:

Most manufacturers recommend that manual transmission fluid be changed every 30,000 to 60,000 miles. Under heavy-duty use, some manufacturers suggest changing transmission fluid every 15,000 miles.
WHY
In a manual transmission, the problem is not so much the fluid degradation, but rather fluid contamination. This contamination occurs over time as the synchronizers, bearings and gears in the transmission wear out. The resulting metal particles then float around in the lubricant. And we all know that oil with microscopic particles of metal in it does not lubricate as well as clean oil. So if these contaminants are not drained out, they will shorten the life of your transmission.
____________
same concept with the axles and transfer case

 

I figured I would go with aftermarket stuff because as long as it's containable with the gm stuff it should be okay. And I change all my drive line fluids and coolant every 25k-30k And oil every 2,500.

 

There is no benefit in changing fluids sooner than the recommended intervals without reason. All you do is throw money away. If the book called for fluid changes every 25K miles then by all means do it, if it says that 100K is fine then your spending 300% more than you needed to.

 

Recommended by the industry or by the Manufacturer's specific recommendation?

Keep in mind, the manufacturer, sells vehicles on low maintenance costs over the life of the vehicle!

Vehicle manufacturer's are now recommending oil changes every 5k-7.5k miles on conventional oil. Does that make the engine last longer? No way, they cut the price to sell the vehicle/sell on low maintenace, and want the vehicle back for repairs to make the real money!

What negative effects does the gm 100k dexcool cause if you wait until 100k miles to change it?

Changing the fluid, prevents premature wear and failures of all components involved in the system, in the long run, saves you money.

If you intend to stay in your rig for a long time, change those fluids at the whole industry recommended intervals!

 

I agree with hummerz, and also I tow with mine quite a bit. And I work at a shop so I get all parts and fluids way cheaper than auto zone and all that. And if I were to get rid of it all the records make the truck look that much better.

 

If it makes you feel better, do it. Back when oil was recycled by dropping a rope in it to wick and filter the oil product out and into the next barrel oil needed to be changed at 3k miles. If you feel the need to used full synthetic oil and keep changing it at 3k miles go ahead, it does not make the car "better". If the manual states to change fluid under adverse conditions at 1/2 the recommended interval do it but don't believe that by doing so under normal conditions that the vehicle will last twice as long or be healthier. A favorite line I remembered from one of the tech books- decreasing the interval between greasings does not make the bearing last longer, it does make more mess to clean up.