Diff setup troubles

Bretto · Post by **Bretto** » Sun Feb 27, 2011 10:13 pm

I spent nearly 16hrs this weekend dinkin around trying to get a good gear pattern in my D44. To give some background, these are used gears but out of the same case they came from. I was just changing the carrier bearings. I can get a relatively nice pattern centered on the drive side but the coast side is less than desirable where it sits high and toward toe. I even have the backlash to the max between 9-10 thou. I'm at the end of my rope. I was stupid and didn't measure or take a pattern reading before I changed the bearings to get a reference. Should I be happy with a good drive side?

idiocrates · Post by **idiocrates** » Sun Feb 27, 2011 10:47 pm

sounds to me like the pinion is too shallow......any way to post up a picture of the pattern? also...toe contact would indicate the ring gear needs to be moved away from the pinion.

Bretto · Post by **Bretto** » Mon Feb 28, 2011 7:50 am

Agreed but my backlash is already at its max, I can't really push it out any further.

idiocrates · Post by **idiocrates** » Mon Feb 28, 2011 8:42 am

which is why you need to unshallow the pinion....in other words....move the pinion closer to the centerline of the ring gear. I assume you have determined the overall shim stack of your carrier and are adding and subtracting equal amounts to either side while setting backlash...right? Also.....if sideplay is within tolerance throughout the face of the ring gear...and backlash cannot be set to within tolerable limits it could indicate that there is some problem with the case itself. have you verified both the cone and cup numbers on your pinion inner bearing? they are correct...right? Hou much of a shim stack are you using under your inner cup? Are you mic'ing the shim stack or reading depth of the pinion with a dial indicator? I found some variance in pinion depth can be injected into the measurements unintentionally by not setting the preload of the pinion consistently....so pay close attention to this step.

Bretto · Post by **Bretto** » Mon Feb 28, 2011 9:23 am

Ya I'm good with the backlash setup of moving shims from side to side as needed. Sideplay? Are you talking run out? Ya its good. I can set and change backlash where ever between 6-10 thou just fine. Just cant get a happy pattern between changing the backlash and pinion depth.
I cant say I looked at the pinion bearing numbers, it didn't cross my mind that they would wrong since I wasnt changing them. I only changed the carrier bearings.
Yes, I'm measuring the shims individually with a micrometer
Right now the set up is .024 on the pinion shim pack and backlash is maxed at 9-10.
When I was setting everything back up to take a reading, I didn't have any preload shims on the pinion, I was just tightening the pinion nut enough to where it had a slight drag to emulate the needed preload.

Post by **wesk** » Mon Feb 28, 2011 9:58 am

I was just tightening the pinion nut enough to where it had a slight drag to emulate the needed preload.

Which manual are you using? Setting preload with your elbow will not be consistent and your results will always be inconsistent.

Bretto · Post by **Bretto** » Mon Feb 28, 2011 10:24 am

beam type inch pound torque wrench.

http://www.ringpinion.com/Content/HowTo ... ctions.pdf

DANA
D25 . . . . . . . . . . . . . . . .12-15 . . .6-7 . . .6-10 . . .55 . . .50
D27 . . . . . . . . . . . . . . . .12-15 . . .6-7 . . .6-10 . . .55 . . .50
D28 . . . . . . . . . . . . . . . .10-13 . . .5-6 . . .6-10 . . .55 . . .50
D30 . . . . . . . . . . . . . . . .12-15 . . .6-8 . . .6-10 . . .55 . . .60
D44 . . . . . . . . . . . . . . .14-19 . . .6-9 . . .6-10 . . .55 . . .60
D50 . . . . . . . . . . . . . . . .14-19 . . .6-9 . . .6-10 . . .65 . . .60
D60, 61 &70U . . . . . . . .17-30 . . .8-10 . .6-10 . . .110 . . .80
D80 . . . . . . . . . . . . . . . .25-40 . . .9-11 . .4-10 . .175 . . .90
6-9 inch pounds pre-load for used pinion bearings
6-10 backlash

Post by **wesk** » Mon Feb 28, 2011 11:24 am

Those numbers do not agree with the stock axle manual numbers. Try the correct manual TM 9-1804B or the civilian SM 1002. I like the civvy SM 1002.

The correct torque when setting pinion bearing pre-load is 200-220 Ft Lbs on the pinion nut for each measurement check and then check rotating resistance with inch pound torque wrench which should be 10-25 In Lbs.
I think the 6 figure for used bearings is a bit low. I would stay in the low end of the new limits spec between 10 and 12 for used bearings.

I'll dig out the SM 1002 and scan the pages for you. I also have a PDF copy of the Spicer/Dana Light Axle Service Manual I'll send you tonight.

Bretto · Post by **Bretto** » Mon Feb 28, 2011 9:51 pm

Here is a link to some pics. Hopefully they show up. The coast side is obvious. Look for the gear set-up folder.
Thanks

http://s1201.photobucket.com/albums/bb356/1brale/

Post by **wesk** » Mon Feb 28, 2011 10:30 pm

idiocrates · Post by **idiocrates** » Tue Mar 01, 2011 2:22 pm

I'm no expert for sure....but after looking at your pics I'm still going to go with the opinion that you need to put more shims behind the cup of the inner pinion bearing.....and move the pinion closer to the centerline of the ring gear It looks to me like you're a little high on the driven side too....at least I set mine deeper....such that the scuff was equidistant from the face and the flank of the tooth.....but I realize there are other acceptable patterns. Have you tried a large increase in the shim stack behind the pinion inner bearing just to see how it would alter your scuff pattern? That was how I eventually homed in on mine.....got my maximum and minimum.....went back to maximum and started working my way down in small steps until I liked the pattern. And yeah.....it actually took me a couple of days to get there. Really clean shims help too....plus a good micrometer. I would mic each individual shim and then mic the entire stack just as a double check. How easily does your carrier come out of the pumpkin? I had to pry mine out every time which only adds to the frustration. One thing that did work for me anyway.....once I had the pinion preload where I wanted it....if I had to alter the shim stack under the inner bearing I adjusted the shim stack under the outter bearing accordingly and all but once was able to achieve the same preload....or at least so I think.
One other thing.....my ring gear and pinion were totally shot....and the new gear set I got had totally different numbers etched into the pinion. I initially though I could do the math and apply the numbers from some of the charts on the internet to get my initial shim stack.....this didn't work for me. Either my original shim stack was wrong.....or I mic'd it wrong....or something. Of course this could have also been caused by my new pinion bearings. Bottom line though.....I found no correlation between old and new shim stacks.

Bretto · Post by **Bretto** » Tue Mar 01, 2011 2:52 pm

Ya, end result comes down to getting a good pattern. I dont think anyone relies on the scribed #'s at the end of the pinion.
Im going to give it another go round. Im sure my wife will be thrilled. I think I'll try to focus more on the coast side.
My carrier is snug and I have to pry it out but its not that big of deal. Only part that I dont care for is removing the the pinion race.

Bretto · Post by **Bretto** » Wed Mar 02, 2011 6:17 pm

Ok I was able to get a pretty good pattern from face to flank on both the drive and coast but the trade off was to open the backlash up to 12. Its like a give and take game. Is 12 going to be a problem? I assume these could be the original gears and maybe worn that much?

RimfireJim · Post by **RimfireJim** » Wed Mar 02, 2011 8:26 pm

This is a timely thread, as Stuart and I will soon be tackling this on a replacement gear set for a Dana 25. I've set up the gears in the dif on a '55 Chevy, but it used threaded adjustments for the carrier and a crush sleeve for pinion preload, and I was just replacing carrier bearings and not gears.

When we removed the old pinion bearing cups in the Dana 25 with a punch, we found it destroyed the old shims. Is there a way to go through this process of iterating on shim thickness without destroying the shims you just got done putting in on the previous round? I could make a special puller or pusher, but there doesn't look like much surface to work with except for the two cut-outs in the housing casting.

Bretto · Post by **Bretto** » Wed Mar 02, 2011 8:33 pm

I started off by ruining the pinion shims but found I could get right on the edge of the cup and slowly nudge it out enough to where I then could get between the shims and the cup to drive it out the rest of the way. Its the beating the kills them. If you were to make some sort of puller, having a constant pressure shouldn't damage them.
GOODLUCK!
I think my wife will kill me if I even think about looking at the D25. Luckily everything in it looks fine other than seals.