swilson84

I installed a new rear end gear kit (3.73) which included new bearings. The backlash is correct and the preload on the pinion is correct, but it still howls on light acceleration and when turning right. What would you check next to fix this situation?

427Roush

I had 3:73 gears in my 07 and couldn't stand the howling noise. I swapped to 3:55 and changed the rear tires to Cooper RS3 from Nitto NT05. Minimal noise now. I also installed the Roush off road exhaust (Borla). These mods made a difference for me.

steel pony

Your shim could be off? Might need to uninstall and repack everything...
I've only helped on a few gear installs, so no expert here, but i do know that changing the tires and exhaust won't reduce gear howling, they will only cover it up,or drown it out...

drewsky

What's the brand of gears and did a shop install them or yourself? I know Ford Racing is the ONLY brand to use when gears are involved

steel pony

+1000 on this!

Motive gears are extremely noisy (especially the 3.90's), Yukon gears can be OK, but a little noisier than the FRPP gears.

edwin108

Assuming you have an limited slip diff, did you remember to add friction modifier to the oil?

swilson84

I installed them myself with some help from friends. The Ring and Pinion are Ford Racing and the bearings are Timken.

BlindGUYnAR

^ maybe ^

Did you get a good contact pattern between gears?

swilson84

I did add the friction modifier and I did get a good contact pattern.

drewsky

Fords are some of the trickiest rear ends to install. I drove an hour and a half away to go to a specialist that has a 2 week wait to get into. They are a licensed Yukon dealer and use them in all of their installs EXCEPT the fords. They say FRPP only! I'll take their word for it since their 50 years in business and very very high reputation! Anyways they had a new guy install my 4:10's in my 06 gt and he took his time. The owner took it around the block came back in about 40 seconds and right back to the bay and up on the lift.. Brand new set in 2 hours later and the owner did it himself! Be explained all this to me that the fords are tricky as all hell and they need FRPP only.. The best shop in the state with a two week wait list 50 years in biz I'll take his word. Especially since I saw first hand what happens when their not pin point perfect... I would get a new set and have a shop do it. Sorry you hear this after the fact but the hard truth, the whining will only get worse