If you want the correct readings you'll have to do it by the book, take it all apart. There's no half way when the measurements are that clsoe. My truck has 90k miles on it and I just replaced the third front seal now. The first was done under warranty, I did the last two. They seem to go out about every 30k miles. I now put a mark on the pinion and nut, then put the nut back to the same place that it was. I now tried putting one quart of dino oil 85-140w and the rest with the synthetic that belongs in it. I run long non-stop trips usually 950 miles on the first day. It seems my customers whos trucks are used locally don't have these issues, just the ones that run on the highway. I think the axle has a flaw in it. The oil shoot at the top where the gear lube is thrown in has to come out through the bearing. If you look at it inside of a dana reverse cut 60 axle, it has a relief shoot out the bottom for the oil to come out. The only way for the oil to get out of the AAM pinion cone is through a spinning bearing. I think it's building up just enough preasure to be a headache with synthetic. Every seal I have taken out looks like new. I'd feel better if I could see something wrong, I could be grasping at straws here. I have a customer who runs hot shot, he stoped using synthetic because he got tired of replacing pinion seals. One of his trucks has almost 600k on it and the other over 200k. I'd take a dana any day.
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93 250 2wd xc 354 auto 265k
04. 5 3500 4wd cc dully 373 6 speed 90k