WFOALASKA
TYF Newbie
Gear noise HELP 2005 Tahoe new 4.56 rear gears, .007 pinion shim, back lash .007, pinion preload 23nm, total preload 39nm.
- Thread starter WFOALASKA
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WFOALASKA
TYF Newbie
Slight whine, growl on deceleration on and off. Quiet hard acceleration, and slight whine at constant speed but on and off. Gears are Motive, non performance. First run was 1 mile and horrible growl on deceleration. Brought back to garage and checked them over. Found pinion preload loose. Removed shims on crush sleeve eliminater, reset to 24nm. Patter same carrier preload same. Back out 2nd run, now slight on and off growl whine on decel. Quiet acceleration. With this pattern, could the pinion depth be too deep or shallow?
WFOALASKA
TYF Newbie
Ok, thinking mabey take .001 or. 002 out of pinion depth. Open lash to .008 or .009. I will post the paint pattern before the ones i have now. To show what it moved to.
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WFOALASKA
TYF Newbie
Will gears be noisy if the pinion depth is a smidge off? Like .001 to .004?
swathdiver
Full Access Member
First set of pics looks too tight. Second looks like they move off-center a little. The backlash on the 900s is .003 to .010 with the preferred numbers being .005 to .007. I'm far from an expert though. There's a few guys on here who have done it and posted pics about it.
@Matthew Jeschke @Erickk120 @asand @George B @ls1frc
@Matthew Jeschke @Erickk120 @asand @George B @ls1frc
George B
¯\_(ツ)_/¯
Sorry, I am not going to be of much help on this one.
WFOALASKA
TYF Newbie
Thanks guys. Have a game plan, bringing it back in garage. This is my first time doing a full, new gear set. Figured out what im doing wrong. Will show some pattern pictures after doing them correctly.
swathdiver
Full Access Member
Give this thread a bump around 9AM your time when these guys start waking up or get back from church. They'll be more people around to see this post.
Erickk120
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First 2 pics assuming you didn't screw the preloads look pretty dang close, going from that, I would have pulled .002-.003 thou of pinion thickness at a time,check what the pattern looks like and then bring it back to original point if too shallow and add .002 thou and compare the difference between both patterns, it will tell you where to go. It seems most of the time you get whine on the coast but quiet on drive side means the pinion is slightly deep. What is the speed range you are getting whine or is it constant?
Now the last set of pics, the compound is way too thick, try to use less oil in the compound and when you roll a pattern only coat 4 teeth and also look at the negatives of other teeth painted, it will give you a better idea of the true pattern. The last 2 pics I cant tell if you added or removed, but it looks too deep to me, and the amount of compound doesn't help.
Also some gears the lower tend to have a little noise sometimes, not saying this is your case, but it happens sometimes. I noticed you are using newton meters to measure, did you mean that or is that actually 23 inch lbs of preload of rotation in the pinion, I believe spec is between 16-20 inchlbs according to the yukon manual, but I've seen ppl get away running in the higher end of 20-25 inchlbs just curious. Motives spec is 7-9 thou backlash and I assune the .007 pinion shim is the shim for preload with the spacer, and lastly your 39 nm preload I believe is your total rotational torque assuming that it is inchlbs and not nm to the carrier with pinion preload installed I believe its too high of a reading for the bearings.
If I math and read correctly 23 (inchlbs) pinion preload-39(inchlbs) pinion with carrier installed preload X 4.56 gear ration = 72.56 inchlbs of preload to the carrier which it would be too high. I know a lot of people say to just stack them til you cant pull the carrier by hard, and never have a problem but to each their own. I cant recall the specs for carrier preload but i believe 30/35 inchlbs is the middle ground for those. Dont quote me on that, I haven't touched an axle in a long time. I have those in my notes somewhere I will have to look around to be precise.
Anyways am just rambling on but its to get an idea of how things go wrong, setting these is simple but its the little details that get you.
Now the last set of pics, the compound is way too thick, try to use less oil in the compound and when you roll a pattern only coat 4 teeth and also look at the negatives of other teeth painted, it will give you a better idea of the true pattern. The last 2 pics I cant tell if you added or removed, but it looks too deep to me, and the amount of compound doesn't help.
Also some gears the lower tend to have a little noise sometimes, not saying this is your case, but it happens sometimes. I noticed you are using newton meters to measure, did you mean that or is that actually 23 inch lbs of preload of rotation in the pinion, I believe spec is between 16-20 inchlbs according to the yukon manual, but I've seen ppl get away running in the higher end of 20-25 inchlbs just curious. Motives spec is 7-9 thou backlash and I assune the .007 pinion shim is the shim for preload with the spacer, and lastly your 39 nm preload I believe is your total rotational torque assuming that it is inchlbs and not nm to the carrier with pinion preload installed I believe its too high of a reading for the bearings.
If I math and read correctly 23 (inchlbs) pinion preload-39(inchlbs) pinion with carrier installed preload X 4.56 gear ration = 72.56 inchlbs of preload to the carrier which it would be too high. I know a lot of people say to just stack them til you cant pull the carrier by hard, and never have a problem but to each their own. I cant recall the specs for carrier preload but i believe 30/35 inchlbs is the middle ground for those. Dont quote me on that, I haven't touched an axle in a long time. I have those in my notes somewhere I will have to look around to be precise.
Anyways am just rambling on but its to get an idea of how things go wrong, setting these is simple but its the little details that get you.
