Ok Im planning on building a car for the silverstate/pony express races in Nevada. In another post of mine someone put forth the idea of keeping the rear gear oil cool. So my idea is simply(maybe not havent really tried yet, but in theory) drill and tap a hole either into therear cover or housing (would drilling and tapping a hole above the pinion bearings be a good idea, so they would get the "cool" oil first, or is there a better place, would making a hole there be detrimental to the housing strength? That would be the return obviously. the pickup would most likely be on the cover, using a stainless hose going through the body somehow into a cooler panel, like trans cooler or oil cooler type of thing( cant remember the exact name at the moment.using an electric oil pump to mave the fluid, with maybe some sort of temp gage. unless of course this is all really trivial, not necessary in which I wont worry about it, but it was brought up so I figured what the hey.

NASCAR teams use a little belt-drive pump bolted to the rear end housing or an axle tube, that runs off of a pulley that's under the drive shaft yoke bolts. They use a small cooler like a Setrab or something. They usually mount the oil cooler behind the driver's seat where the back seat would go, under a hump so that it's outside the car, with a fan blowing air through it; and the rear end cooler on the right side. It's not real important where the cooled oil goes; only that you get the heat out of the rear end housing, so that it doesn't build up to a real high temp in there. Which is not a trivial matter at all.

I wouldn't bother with the temp gauge... again, the NASCAR guys don't seem to find it necessary.