Crickets in the Pumpkin

[Lynxopie]

I need some Help!
I recently had a local performance shop install 4:56 gears (G2 Genuine Gears)with new timken bearings and a true trac into my '05 2wd Edge to accomodate the 32' BFG's. The axle is the standard 8.8 with 28 splines. The break in period went well but then I started to hear a high pitch warble (sounds like a field of crickets) between 35-45mph and again around 60-70mph(just my luck cruising speed!) the noise eventually got louder and is constant from 35-80mph while accelarating or coasting. THe noise seems more noticible when things are warmed up.

The shop has rechecked everything and even refilled the gear oil twice. They could find anything wrong and the R&P pattern is perfect. I have checked the u joints, rear output on the tranny and the "chirping" noise is definetly coming from the front of the differential (pinion area) and changes pitch slightly when accelerating vs coasting. The only clue from the performance shop is that they say the R&P gear teeth surfaces seem to have had some heavy machining lines on them when they were manufactured. The mechanic is suspecting that the gears are what is creating the noise.

Has anybody else experienced anything like this? Have true tracs ever created high pitch warbling/chirping noises? I am assuming bearing failure would be a lower grumbling sound...
Thanks in advance

 

[mhughes165]

how many miles are on the setup, a breakin period for gears is ususally about 500 miles for initial break in

 

[Lynxopie]

The truck has 25,300 miles on it today. It has been about 1,200 miles since the new gear setup. The vehicle had its frist run for about 15 minutes and then sat to let the gears cool, after that I took it easy for the first 600 miles.

 

[cashmoney37]

i had the same thing happend but i have a 7.5 with yukon 4.56. same thing u r talking about. i think it might be a pinion bearing so im changing mine out this weekend.