Gear setup 8.5 "

[Albertaborn]

Awesome thanks everyone for the input. I'm definitely not rushed. Actually I still haven't messed with it but trust me I'm very much a perfectionist. Last time I re-bearinged a 10 speed Mack transmission took me a week but I didn't rush and the thing prob has 100 k on it now. As far as where I'm getting my info this is what I've been following.....

http://www.truckmodcentral.com/forums/f168/gm-10-bolt-rear-gear-install-setup-11732/

 

[Albertaborn]

Well as promised I finally got around to taking some pinion shim out. Pinion shim at .035, pinion preload at 19 in lbs (seems like conflicting info about this value.) Backlash is now set at 0.0085" after a few shim moves. It's weird my coast still seem heavy on the toe and the drive now is quite high.. any thoughts? I haven't messed with it a whole bunch just slipped away for an hour to try he new shim setup

 

[64nailhead]

Well that got worse and looks like you need more pinion shim????

 

[Albertaborn]

I would have to agree. It's weird my coast side didn't really change much

 

[Albertaborn]

Wondering if I should go back to .037 pinion shim and maybe play with backlash?

 

[64nailhead]

What is your carrier preload? And I would agree to go back to .037" pinion and recheck.

 

[Albertaborn]

As far as carrier bearing preload I'm not sure I have anything concrete. I did have to drive in the shims with mild to moderate force. I see what your saying about setting it up with zero backlash measured with a dial indicator then adding 0.005" to each side for a total of 0.010". I just pulled ever everything apart again to change pinion shim back to 0.037" and will try to work out a better way of setting carrier bearing preload. I think out of curiosity I will put the carrier in without the pinion and see how far out I was or am wig he current shim setup. Might give me a good "feel" for how smoothly thing things rolls over.

 

[Albertaborn]

Well with everything as mentioned above this is my pattern with .037 pinion and .007 backlash. First 2 are drive side. Last is coast. When you look close at the drive side it does contact a large portion of the tooth but only is really removing the paint on a small portion . Not sure if it's because my marking compound wasn't 100% room temperature. I held lots of pressure on pinion while turning ring gear

 

[64nailhead]

As far as carrier bearing preload I'm not sure I have anything concrete. I did have to drive in the shims with mild to moderate force. I see what your saying about setting it up with zero backlash measured with a dial indicator then adding 0.005" to each side for a total of 0.010". I just pulled ever everything apart again to change pinion shim back to 0.037" and will try to work out a better way of setting carrier bearing preload. I think out of curiosity I will put the carrier in without the pinion and see how far out I was or am wig he current shim setup. Might give me a good "feel" for how smoothly thing things rolls over.

Carrier preload and backlash aren't the same. Carrier 'bearing' preload is measured side to side with a dial indicator set up the differential or ring gear flat surface. Gear lash is measured from a ring gear tooth.

 

[Albertaborn]

I fully understand the difference. Maybe I didn't articulate either very well. Carrier preload is the amount of force( preload) between the bearing on the carrier and their respective cones. Backlash is the actual distance between the ring gear teeth and the pinion teeth measure in thousand of inches. When it comes to carrier bearing preload what I can see about how to measure it there is alot of varying opinion. Some say use your original pinion bearing preload plus the measured am out to rotate everything divided by ring gear ratio, some day drive shims in with hammer and that you can't get it too tight ( which I don't believe) and then there are few who say strive for zero backlash and add .005 to each side. Some say it's a feel thing on how free just the carrier spins. I know out of curiosity with just the carrier and no pinion in I gave it the big spin and it turned about 3/4 of a turn and didn't feel bound. To achieve that I put shim in first and dropped carrier in and had to drive it in with a rubber mallet with 4 or 5 medium blows. I do have to pry the carrier out nothing crazy but no way am I getting it out by hand.