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wierd gear pattern, help me

whitneyj

whitneyj

NAXJA Forum User
Location
Mayville, WI
Story: I got a 74 hpd44 housing with bearing caps and took the guts out of my 78 hpd44 and swapped them in the 74. The 74 axle didn't have the carrier or pinion or anything in it, so as far as where to go with the shims, I was clueless. It's taken me about 5 hours to get the pinion bearing preload set, not sure what the problem was, but .002 made a 20 in/lbs difference in preload. . . anyhow, once I got the pinion preload good, I set the backlash at .009. Now the wierd part:
ring gear side shims: .078
nonring gear side: 0
innerpinion shims: .020
outer pinion shims:.035
I ran a couple patterns and I'm not sure where to go on this. Hope your guys can deciper my pictures, my cameras on its way out.












Also, it's a used gearset, I understand that's going to throw the pattern off from a new gearset pattern, or at least that's what randy says.
 
Last edited:
It looks like your pinion is too shallow. Add .005 to the inner pinion and subtract .005 from your outer pinion. This will also decrease your backlash, so move a thin shim from the gear side to the non-gear side. Don't worry so much about the backlash until your pattern looks good, because moving the pinion in and out will affect that.
 
Backlash also effects the pattern.Also dont worry about pinion pre-load until you get the pattern right!
 
alright, I got the pattern right, took a step back and looked at it and realized I was going the wrong way with pinion depth. oops. . . oh well it's my first gear set by myself. Now the coast pattern looks pretty good, randy's randp said not to worry to much about the drive side with a used gearset, so overall I'm confident the pattern isn't going to get much better than what I now have. The only thing I'm worried about now is when I press on my new bearings. The setup bearings have a .020 difference between the two setup bearings, so I'm going to shim accordingly and see what happens I guess.... now that I've got the pattern looking ok I'm going to pull out the setup race and drive the new one in and do the same to the carrier.
 
Wildmatt said:
It looks like your pinion is too shallow. Add .005 to the inner pinion and subtract .005 from your outer pinion. This will also decrease your backlash, so move a thin shim from the gear side to the non-gear side. Don't worry so much about the backlash until your pattern looks good, because moving the pinion in and out will affect that.
Click to expand...


Thats shallow?I thought it was too deep.....so was it deep or shallow?I'm trying to school myself on gears before I try to do my own here in a few months...
 
What you need to be more concerned with is the short distance of the tooth, not the long distance. If you look the pattern was on the inside top of the tooth in one of the pics. By bringing the pinion in deeper it will bring the pattern towards the root of the tooth, as well as helping to bring it more towards the center. You need to be more concerned about the placement of the pattern not in the root and not at the tip, and less about side to side.
 
Here is an illustration of acceptable gear patterns.

pattern-ok.gif
 
the pinion was way to shallow, I added .048 to behind the inner pinion race. That brought the pattern centered to the heel and toe, and after I set the backlash, again, it brought it centered face to flank. Now I've got the problem of when I installed the new bearings, now I can't get the carrier in housing because the new bearings are so much bigger than the setup bearings, that and I added shims to the NRG side to compensate for the setup bearings being different by .020 between the two. I should have subtracted shims from the other side and I would've been able
to get the carrier in with a deadblow. I'm off to find a bearing puller. . .
 
don't bother with the puller if you have a dremel. Cut off the outer cage and remove it, then slice through the inner race most of the way. Put a cold chisel in the groove and hit it with a hammer and it will crack and you can remove it. Install the new bearing.
 
I already installed the new bearing, that's why I need to find a puller, I don't want to ruin it.
 
By pulling the bearing off with the 3 jaw puller, you WILL damage it. Infact using a bearing seperator will probably ruin it as well. You'll need to replace the bearing most likely anyways
 
I used to use a 9 inch bearing splitter and the 12 ton press. had about a 50% success rate in getting bearings off in usable shape.

finally broke down and bought the Yukon bearing Puller, Been 100% ever since. In fact doing a D60 tomorrow and not even going to mess with setup bearings. that is an amazing tool.
 
I pulled the bearing with a bearing splitter, I've never had a problem pulling bearings with one, I might not have pulled enough to have a problem yet I guess. I got the pinion preload set, installed the new race, seal and everything, and went to drop the carrier back in it's home. . . bam, zero backlash. . . not sure what happened there, I pulled an even .010 from both sides and pressed the bearings back on. any clues?
 
Alright, a little update from last night. Vettebody-bearing caps were on the right way, I marked them so I'd have to be blind to not get them on right. I'm not sure what happened, but I ended up pulling the carrier bearings 3 times and moving .023 from the rgs to the nrgs which brought my bl back to .007. Now the really really cool part. . . my pinion depth is off. I'm not sure what I did wrong here. The last pattern I ran with the setup bearings looked good, then I replaced the setup bearings with the new ones, I also had to shim the carrier bearings on the rgs to compinsate for the setup bearings being .020 different fro meach other in width. I then installed everything, bam... no good. I took it all apart last night, double and triple checked everything, it's all the way it should be. I didn't lose a shim, I didn't add a shim. I'm not sure what I did wrong. Anybody have any clue, besides error on my part, what happened?
P.S. the pinion preload was still good. ;)
 
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