I've got the stock rear with a set of 3.73's in it. Lately under deceleration, the gears whine really bad. Is there anything I can do to fix it or prolong the life of the rear?

 

nope, i blew mine up the same thing happened. It willl progressively get worse and worse until u can't stand it anymore. Then just buy a new rear. I found some chipped teeth in mine....................

 

U could try re-shimming the pinion gear, but it's basically a matter of time before the rear end goes out.

 

Listen same thing happen to my car, the gears are not set up properly, the backlash is incorrect. IF you get the gears setup properly then everything will be fine again.
My suggestion is not to drive the car until its fixed, and if you have to don't rev it to high

 

if it's whining already i doubt u can reshim them to work, they are already worn and/or chipped. If i where u, i'd buy either a strange 12 bolt, or if u are not going to mod that much buy a stock rear. I just put in another stock rear about 3 weeks ago and I'm just hoping it lasts the summer until i get my 12 bolt, our rears are just pathetic.