I just rebuilt My rearend because all the bearings were shot. I put a Set of 3:55 gears in it. Gas prices are riseing so didnt want the 3:73 agin. It was doing fine. But at 275 miles it started hawling when im going 35 to 50. I thought its supposed to be broken in by then. Is something wrong. Is it normal. And what is the spline on a 2000 gt stock axle? Thanks for the help.

 

It shouldnt be making any noise, something is wrong. The stock axles are 28 spline. How do you like the 3.55s compared to 3.27s? Any noticeable difference?

 

Its a good differance. Im likeing them. Today was the first day to get on them and not bad. So what would be causeing the noise. Every other speed is silent but that speed.

 

My axles are kinda bad would that cause it?

 

not having proper backlash would cause a whine who installed them and into what specs? and more details about your axles being bad will help

 

A friend who is a mechanic. Not sure what spec he did. What is a backlash. Just wanna learn. Thanks

 

were the bearings sit kinda scaped up the outer axles and the splines are a little worn

 

Backlash is the slop when you rotate the diff while holding the pinion.
should be around .010.

 

Backlash is the amount of play between the pinion gear and the ring gear. This measurement is vital, backlash that is set too tightly will result in a lot of heat, while too loose can cause lots of noise and breakage problems. you use a dialindicator with a magnetic base to check the backlash
When installing gears you also should get new shims which allow you to get the correct pinion depth and alignment for the carrier/diff. Depending on the thickness of the shims on one side or another and proper pinion depth will determine your backlash. If you have to much it can cause the whine your describing. That could be my only guess at this point

 

Thank you for your help and the learnings.