Hi everyone, This is my first attempt at setting up gears. I’m setting up new 4.10 Yukon gears on an ARB locker in a rear Dana 44 Rubicon axle (2007 2 door JK). I started with the recommended .042 on the pinion and then .037, .027, .032, and am now at .030. Also, new bearings and good carrier preload. I ran out of backlash with the .027 setup trying to move contact to center and with the .030 setup the pinion seems a little deep on the coast side. With the pinion shims I have I can’t set pinion depth between .027 and .030. Which setup would run the best? Any advice is appreciated. Thanks. -Chris

 

Disclaimer: My gear setup skills aren't the best. But...

1. Are your preloads all within spec?
2. Is the backlash within spec?
3. Are you running the paint check under some load? Having someone on the brakes a little while you spin the pinion helps.
4. Can you do a combination of shims that can get you between that 0.027-0.030 range?

Your drive-side paint looks great. The coast side just needs a tweak on the pinion shims.

But this advice is probably in the "Captain Obvious" category. Wish I could do more.

 

Hi AZJeeper, I appreciate the observations. All preloads backlash etc. are in spec, and backlash around ring gear is less than .001 variance. I’m applying lots resistance when doing a pattern. The caps are at 80 ft/lbs. I’ve checked carrier and ring gear runout and they are good. I can’t get between .027-.030 with the shims included in the master kit. Only .020, .015, .012, .010 shims. At .027 pinion shim the pattern is pushing heel on drive side and toe on coast with min backlash of .006. Even then the coast side appears too deep. Here is a better pic of the coast side showing the depth with .030 pinion. It’s not bad just a hard line towards the root. I don’t know if it would whine on decel like this.

 

Mine is setup a little like yours and yes, I do hear a little whine on deceleration. I switched to Mickey Thompson Baja Boss ATs recently. They are super quiet. Never noticed the whine until I put those on. I guess that's what the radio is for?

Have you given a crush sleeve consideration? As much as I hate them, they do allow for nearly infinite adjustment of the pinion. ...at least until you go too far!

 

I run nitto trail grapplers and maxis razr mt’s. Both run pretty quiet so I know I will hear it if it whines. The crush sleeve just sets your pinion preload (the rotational torque required to keep the pinion turning). The pinion depth is set by shimming between the inner bearing and the pinion head. I’m using a yukon crush sleeve eliminator in this rear end, but I will have to machine about .004 off the large spacer for it to work. Maybe more depending on my final pinion depth. I ordered a 5 shim kit thru oreillys yesterday that should be in today. They didn’t know the shim thickness so I will have to see if it will work. If not I will run the .030/.008 setup.

 

Put it together with .030 pinion and .008 backlash with 30lbs preload on pinion. 2 20 mile break in runs so far and no issues or whine. Had to machine the crush sleeve eliminator large spacer to .506 from .515 to get 30 in/lbs of preload. I’ll try to post pictures of the pattern when I open it up after break in. Thanks