Attention: TDR Forum Junkies 
OK, one more time about rear axle fluid level. I've searched some of the threads and can't find a definitive answer. It may be a non-issue anyway.
The truck is a '97 Dodge Cummins 3500 dually, 4WD. Last year I replaced the rear axle (Dana 80) fluid with synthetic. This year I replaced the front axle fluid and in reading the owner's manual, noted that the axle was to be filled to the bottom of the hole. This rung a bell because I vaguely remembered reading to fill to a half inch below the hole. In fact all the 4WD's I have had back through the years specified something below the fill hole for front axles. I think it is at least partly because of the seals inside the axle ends which are not super effective. And in fact, I think the reason they always specify frequent front axle fluid changes is because these seals also are not too effective in keeping out water.
Anyway, here's the dilemma. The shop manual for my truck specifies filling to the bottom of the fill hole for both axles. Page 3-24 for the Dana 60 front, and page 3-127 for the Dana 80 rear.
The owners manual, page 195 says, and I quote, "The fluid level should be 3/4 inch below the plug in all Dana rear axles. " And, "The fluid level should be 1/2" below in all Dana 60F front axles. "
Last year I did fill the rear axle to the bottom of the fill plug hole, I had checked it before draining out the old and it was at the bottom.
Which is right? Is it really a problem? Should I siphon some out of the rear axle?
BTW, last year when I took the cover off the rear axle, I drove both left wheels up onto ramps, then both right wheels, in order to get as much old fluid out as possible. Then after filling I repeated this to allow new fluid to get into the axle ends and wheel bearings, then added necessary fluid.
Bob
The truck is a '97 Dodge Cummins 3500 dually, 4WD. Last year I replaced the rear axle (Dana 80) fluid with synthetic. This year I replaced the front axle fluid and in reading the owner's manual, noted that the axle was to be filled to the bottom of the hole. This rung a bell because I vaguely remembered reading to fill to a half inch below the hole. In fact all the 4WD's I have had back through the years specified something below the fill hole for front axles. I think it is at least partly because of the seals inside the axle ends which are not super effective. And in fact, I think the reason they always specify frequent front axle fluid changes is because these seals also are not too effective in keeping out water.
Anyway, here's the dilemma. The shop manual for my truck specifies filling to the bottom of the fill hole for both axles. Page 3-24 for the Dana 60 front, and page 3-127 for the Dana 80 rear.
The owners manual, page 195 says, and I quote, "The fluid level should be 3/4 inch below the plug in all Dana rear axles. " And, "The fluid level should be 1/2" below in all Dana 60F front axles. "
Last year I did fill the rear axle to the bottom of the fill plug hole, I had checked it before draining out the old and it was at the bottom.
Which is right? Is it really a problem? Should I siphon some out of the rear axle?
BTW, last year when I took the cover off the rear axle, I drove both left wheels up onto ramps, then both right wheels, in order to get as much old fluid out as possible. Then after filling I repeated this to allow new fluid to get into the axle ends and wheel bearings, then added necessary fluid.
Bob
