14bolt FF New Gear Issues PART II - Yea, I may be an idiot...but I'm not stupid

[ZombieK5]

Got TOTALLY fed up with the first ring gear set I bought. Bought a second ring gear set (from Yukon again). I also have a second Eaton TrueTrac carrier. Eaton replaced the first one, it has modest runout issues on the mounting surface.

2nd Ring gear in. Pinion is set for Preload.

Followed set up procedure and measured Backlash.

Highest point is .011
Lowest is .005

Rest seems to be in the 006 - 008 range.

Can't figure this out. I filed ring gear surface for burrs.

I mounted, removed and mounted the carrier 2 or 3x. Carrier Preload is tight. Bearings are oiled.

After almost jumping off the roof I spun the pinion 8 or 9x and the low Backlash number MOVED several teeth down.

Is this a pinion issue???

What would I look for??

 

[Chickntrk]

Backlash is .003-.012, you’re right there, maybe I don’t understand what the issue is?

 

[ZombieK5]

Backlash is .003-.012, you’re right there, maybe I don’t understand what the issue is?

The issue is the backlash should not vary more than 002. So if the gear appears set at 007 than the gears, as you check other teeth, should not vary by more than .002

From my understanding that means .006 - .008 is acceptable with .007 right in the middle. I have a range of .005 - .011 with .008 right in the middle.

Is this wrong theory?

 

[nvrenuf]

Could an acceptable variance of .002 be .005-.009 (on your .007)? .002 in each direction.

 

[Wes Harden]

My thinking. Rotate the ring gear on the carrier and re check. Maybe the run out on the 2 parts are stacking? Try 180*

 

[ZombieK5]

Could an acceptable variance of .002 be .005-.009 (on your .007)? .002 in each direction.

THAT is something I have never confirmed. I thought TOTAL variance could only be .002

 

[ZombieK5]

My thinking. Rotate the ring gear on the carrier and re check. Maybe the run out on the 2 parts are stacking? Try 180*

I was going to do that BUT if i turn the pinion 7 or eight times the variances MOVE down several teeth.... Does that say there is an issue with the pinion?

 

[Wes Harden]

It does seem suspicious.

 

[ZombieK5]

It does seem suspicious.

Well... Could this be my issue.

I pulled everything apart and was starting over when I found a bend bearing cage on the outside pinion bearing. Zero idea how it got there. I press the bearing in ONLY putting pressure on the inner race...

Ordered a new Timken. Should be here Thursday.

 

[Wes Harden]

If you are asking about the bent cage, it shouldn't have any effect on the trueness of bearing.
It might cause wear, thought that appears to minimal

 

[ZombieK5]

If you are asking about the bent cage, it shouldn't have any effect on the trueness of bearing.
It might cause wear, thought that appears to minimal

Hmmmm, Well, I am putting in a new one. The one if the image was new, I just dont know when it get bent. Trying to hit all the bases to figure out the issue. More to follow

 

[1-ton]

I have a 14-bolt FF rear diff in my 1-ton truck that has about 300,000 miles on the original ring and pinion set. I bet if I measure my backlash it would make your gear set seem like perfection, yet my rear diff still runs down the road fine.