I recently bought a 2004 CC 2wd D/A for towing a trailer, and improved fuel mileage over a gas truck. I know that the transmission temp gage is fairly new, as an option, from GM. Have any of you installed a differential temp gage? I drive to the Keys once or twice a year and it a 1200 mile trip one way. We usually drive it straight through, 16 to 18 hrs depending on traffic. You could fry eggs on the differential by the time we arrive. Just wondering what others that tow have done or thought about. What the temps are and where to locate the probe? What weight oil to use? I have read that some are using 75-140. That leads me to one last thing. What brand of differerential oil do youcan be use as a replacement for GM's. GM want $26 to 30 a quart. I can't find the GM spec that they list in the manual to see what other fluid can be used. I called three different dealers and got three different answers.


Scott

Get a Mag Hytec cover,


It doubles the axle fluid capacity to almost 8 qts. and has a dipstick to check fluid level and a tapped hole for a temp probe.


Look here Mag Hytec (http://dieselplace.com/forum/forum_posts.asp?TID=10786&PN=2)


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If you are concerned about warranty issues buy the GM grape juice and be done with it.

Run Schaeffers 75w-140 synthetic gear lube w/ moly.


It will drop the temps.


Order from Eric.

BART,


Haven't done the test on a Duramax yet (but have on that other brand, the paint burns off the factory cover in about 5000 miles so that's what got me interested in seeing what was going on) we installed one of our PML aluminum high capacity pans and a diff temp gauge and got almost 30 degree drop across the entire operating temps. call me if you have any questions and the pans and gauges are on our site.


Mark @ DPPI