4 Wheel Drive/SUVs: driveline question, automatic transmission fluid, synthetic lubricant

Question
Hey i have a 2000 gmc sierra 1500 with a 4 inch lift. i was recently on the highway when unexpectedly my u joint snapped and i lost my driveshaft destroying it, then i had to drive 30 miles with just front wheel drive. i was wondering what the fluid is that leaked out where the sliding yoke slides into the transmission. i checked all the fluids and they are good but i dont know what kind of lubricant to put inside. any help would be great.....and also do you think it is contaminated in there? should i rinse it out or something? also my new driveline will be steel instead of aluminum will this cause a problem????please help me  

Answer
Casey,

First, check out your drive line angles.  With the lift, you would need to make sure that the u-joints have the same angle coming out of the transfer case and the differentials.  If not, your u-joints can get in a bind and break.

The yoke is sliding into the transfer case, and not the transmission.  This unit is separate from the transmission, and has it's own fluid.  This is usually checked through a plug in the side of the transfer case.  Most take automatic transmission fluid, but some require a special synthetic lubricant.  I doubt if it's contaminated, but it wouldn't hurt to change it with new fluid.

I would suggest that you purchase a repair manual for your GMC, as it will give you all the specifications for fluids, and how to change them.

Carl