Originally Posted by
cowboywildbill
I think the new torque convertor and the tighter trans with less % of slippage and the larger cooler and maybe better engine temp control play into the lower LML's trans temps. I think a lot of the higher temps on the LBZ were due to the engine temps fluctuating and the trans cooler lines picking up heat from the radiator rather than dumping it in there. As for the rear, it is the same internally from what I've read, But the axle tubes are now 4" in diameter and larger than before to increase the wieght rating. I don't know if the larger tubes help with cooling the rear diff fluid or not. I wouldn't think so but who knows? I changed our rear diff at 1,000 miles. It only had 2.5 quarts of fluid in it. I let it sit level for a 2 hours before I drained it on a very warm day. I put just a little under 4 quarts back in and stayed the recomended 1 and 1/2 inch below the fill hole. I think the rear is the most critical first early maintance for break in that should be done. And then engine oil.