GEAR INSTALL HELP Ford 10.5 VIBRATION at 60 and above

yjwrangler95 · Aug 17, 2015

I need some expertise. I've done a few sets of gears and this one has me stumped. I've attached pictures of the setup before it was run and after. I have a vibration over 60 on the coast side, above 60 it is on the coast and drive side. Only thing to change was the R/P. 3.73 to 4.56 Its a 2004 Ford Excursion. It never vibrated with the 3.73's. I've run 85 many times with no vibes.

All new bearings, new crush sleeve, new yukon 4.56 gears. BL was .0085 before and after running, pinion preload was set at 25 in/lbs. I have 25 in/lbs with the carrier install and shafts as it sits. I have not removed the carrier yet to check pinion preload. I think it will be within spec of 6-8 in/lbs now that the bearings have been broken in.

Attached is the pattern, yellow is pre- break in, and blue is after about 100 miles. I need some expertise on this. Please help.

THanks

ranger11 · Aug 17, 2015

Backlash needs to be set 6-10. Thats where Id start..

yjwrangler95 · Aug 17, 2015

Sorry forgot a zero. BL was 0.0085 before and after break in.

al1tonyota · Aug 17, 2015

Your driveshaft is spinning faster! Could be u joint and showing up more from spinning faster!

RustyC · Aug 17, 2015

Was the driveshaft separated during the install? If so, are the yokes still in phase?

yjwrangler95 · Aug 18, 2015

Pull the drivehshaft, sent it off to check balance and get new joints. Pinion angle was off, its a non cv shaft with the pinion pointed directly at the transfercase.
The shaft was not seperated during the install. I will report back after adjustments are made. Hopefully a Ballace Job and setting the pinion angle will correct the vibration.