My wife says it is annoying so now I have to fix it. Well hear is my problem:

I had gears installed last week and broke them in (steve00ram360 wrote....drive 20~30 min then let them cool all the way down, then every 30 minutes of driving, let it cool for 20 minutes..I did this for a couple of days)

There is a humming/whistling sound...I am pretty sure from the rear of the truck....when I step on the gas (not right away) and get to about 25 or 30 then you can really hear it. When you let off it is not as loud but you can still hear it and then when stepping on the gas it is loud again. I have had it back and the shop showed me it was a perfect pattern. I have set up Ford 9", Dana 44 and Dana 60 but not a corporate 9.25....I am assuming the pattern should be somewhat the same. The only reason I did not do this myself is because I did not have the time.

Any ideas would be great and specs of truck are below
Brad

 

I jacked it up at lunch so i know it is in the rear of the truck

 

My first task would be diff oil check. Makes sure there is enough. My second guess would be ring/pinion lash. I know you can buy that white, paste like stuff to check gear lash. Good luck.

 

yea im going to guess that the shop didnt set them up right and the backlash is off. i would take it back right away and have them check that out before it damages the gears or the rear.

 

Yeah I checked the pattern myself when the diff cover was off and it looked good. I am taking it back in this morning and looking at it again.

 

Well I have replaced all the bearings and reset up the gears 2 times. We had another pair of eyes look at it and we think it could be defective gears. Has anyone heard of this before?