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View Full Version : Need gear setup help in the towpig



gonecheenin
03-07-2016, 12:42 AM
Need some feedback on a gear pattern (I am horrible at reading these) in my 89' D70HD

Usually I don't stress too much because I've had good luck running used gears with what ever pattern is close enough as long as the backlash and pinion bearing preload was right, but these are new 3.54 gears that will be hauling anywhere from 7500lb up to 22,000lb in my compound turbo Cummins Chevy that generates over 700lbft of torque so I'm being a bit paranoid with this setup.

Pinion with previous shims set @ approx 25inlb rolling torque and carrier with no preload set @ .010" backlash;

Drive side
http://s1024.photobucket.com/user/gonecheenin/media/000_0384_zpsgof3hc2d.jpg.html?sort=3&o=3http://i1024.photobucket.com/albums/y306/gonecheenin/000_0384_zpsgof3hc2d.jpg (http://s1024.photobucket.com/user/gonecheenin/media/000_0384_zpsgof3hc2d.jpg.html)
http://s1024.photobucket.com/user/gonecheenin/media/000_0385_zpsknnjpykp.jpg.html?sort=3&o=2http://i1024.photobucket.com/albums/y306/gonecheenin/000_0385_zpsknnjpykp.jpg (http://s1024.photobucket.com/user/gonecheenin/media/000_0385_zpsknnjpykp.jpg.html)

Coast side
http://s1024.photobucket.com/user/gonecheenin/media/000_0387_zpsza4lffdl.jpg.html?sort=3&o=0http://i1024.photobucket.com/albums/y306/gonecheenin/000_0386_zps9h50qith.jpg (http://s1024.photobucket.com/user/gonecheenin/media/000_0386_zps9h50qith.jpg.html)
http://s1024.photobucket.com/user/gonecheenin/media/000_0387_zpsza4lffdl.jpg.html?sort=3&o=0http://i1024.photobucket.com/albums/y306/gonecheenin/000_0387_zpsza4lffdl.jpg (http://s1024.photobucket.com/user/gonecheenin/media/000_0387_zpsza4lffdl.jpg.html)

justin'sbig7
03-07-2016, 10:05 AM
Your pics are a tad blurry but it looks like you're fairly well centered in the tooth both in and out, toe and heel... I would maybe like to see it a little deeper towards the heel... IMHO, if it were mine, I would likely run it how she looks and check the tooth wear after a couple hundred miles because I'm paranoid lol!

gonecheenin
03-07-2016, 12:51 PM
IMHO, if it were mine, I would likely run it how she looks and check the tooth wear after a couple hundred miles because I'm paranoid lol!

I was thinking about that but didn't know if once they started wearing it would be too late to change them. I think I'm going to tighten up the backlash a couple thousandths and check the pattern again for any changes.

Christopher
03-07-2016, 01:23 PM
It looks nice to me considering picture quality. The edges of pattern look soft/feathered and centered in the face/flank. You can always change depth one way or the other to see the difference.

5 SPD XJs
03-10-2016, 07:57 PM
I've always thought .010 was max backlash. I think tightening it up a couple would be a good thing, don't go below .007. Go by any instructions with the gear set you have, but I always thought the heavier axles have preload on the carrier. I'd add to that on the gear side to close the backlash. I too am suspicious and look after 500 miles. Especially new gears. Gary
Jay, I just looked up Billavista, He says .015 more than space. I have gone .010. That alone will close backlash to much if you put it all on the gear side. I should have looked before typing

gonecheenin
03-11-2016, 09:39 PM
yeah the required preload is .015" and I currently have .005" measurable back and forth so I think I will add .003" to the ring gear side tomorrow while I have the setup bearings in and see what my backlash & pattern is before I install the pressed KOYO carrier bearings.
Don't know if I can shrink the assembly enough in the freezer to get it into the housing without a housing spreader to do the full carrier bearing preload but if I can get over .010" preload I'm hoping that will be close enough.

tjblair
03-12-2016, 08:41 AM
Run it