I am working on an 06 V6 with an FRPP traction loc and a set of Yukon gears because Ford does not have the 3:73s for the 7.5 anymore. I set them up the same way I have done every other gear job and I cannot get them quiet. The car gets a very high pitched whine that starts around 30 mph and gets louder the faster you go. I have checked the pattern and it is dead center and everything else is within spec. Anyone had any advice?

 

I had Yukon 3:73's installed by a speed shop. They whine as well. I just learned to except it (for now).

 

I told the shop that did mine that I only wanted FRRPs (4.10s). they were back ordered ordered while I was out of town he ordered Yukons. I drove them up the street and told him to replace with FRRPs. The FRRPs were much quieter.