I have a 2004 Dodge Ram QC that I had 4.56 motive gears with a Detroit Tru-Trac put in about 3 weeks ago. I noticed a whine in the differential at around 45 mph that extended to 55 mph. I was told that this was normal for 4.56 gears... it this true? I am also worried because the noise seems to be extending beyond the initial 45-55 mph range. Is there anything that can be done to fix the problem with the whine? Initially it was only when I let the truck coast after accelerating, but I am starting to hear noise when the truck is decelerating, but after 45 mph the noise stops. Thanks for your help.

 

I just had the same set up installed, no noise or whine. You need to bring it back to the installer.

 

I have 4.56 ---no noise go back to installer