excessiveego

I need to know if this is an acceptable pattern. It does not look like any of the "acceptable patterns" but it also doesnt seem to look like any of the unacceptable ones. Also, if it isnt acceptable, what do I need to do to fix it.

big gear head

The pinion is too deep. Remove some of the shim from the pinion and try again. I would start by taking about .007 out and see what happens. Be sure that you set the pinion bearing preload the same each time and be sure that the backlash is correct each time.

Notice the sharp line at the root of the tooth and how the pattern comes to a point toward the face of the tooth. This says that the pinion is too deep. Pay close attention to the rood and face pattern and don't worry about heel and toe. Most people try to do the heel and toe thing and they are working on the wrong part of the pattern.

excessiveego

bump, any other opinions before I pull it apart again?

big gear head

I'm going to have to blow my own horn again, but you can trust me when I say it's too deep. I've got 32 years experience building rear ends and I owned a rear end shop for 15 years. I can read a pattern pretty well. Your pinion is too deep and needs some shim removed. If you will pay attention to the details in the pattern I will teach you how to read it too.

excessiveego

sorry, didnt mean to question your experience. Just didnt get a chance to pull it apart yet and like to have a few options in mind of the first doesnt work. I only have about .007 worth of shim in it so here's to hoping that is enough.

I dont have the right dial indicator to measure pinion depth so i was winging that part anyway

big gear head

No problem. I don't know you and you don't know me, so you had no idea if I knew what I was talking about.

You need to get a dial indicator. If you don't know what the backlash is then you are shooting in the dark. As for the shims, did you remove the shims from behind the inner pinion bearing race? The 10 bolt is shimmed behind the bearing on the pinion shaft, but I think the 9 bolt is shimmed behind the race in the housing. Check and see if there are shims in there. If you are going to shim it behind the bearing then you need to remove the other shims.

excessiveego

ill give you alittle back story. I took out my pinion bearing so I decided I might as well rebuild the whole thing and change my gear ratio while I was at it. So I have replaced all the bearings and seals as well as gone from 3.27 gears to 3.70 gears.

I do have a dial indicator but I do not have the correct extension so that it can reach the pinion. The backlash is currently set to .005 which is .001 lower than recommended (.006-.010 according to people on here) or (.007-.009 by the company that made my gears) will .001 make that much difference?

Also, I shimmed the pinion with the stock shim behind the race, the stock shim was the thinnest one I had so hopefully removing that will be enough.

big gear head

Use the manufacturer's recommendation for backlash settings. Also use a .001 feeler gauge to see if you have the bearing race completely seated. Sometimes a burr or something will keep the race from fully seating in the hole. There should be somewhere around .025 to .030 shim for the pinion. If you only have .007 and need to remove that then it seems like something is wrong.

Base91

iTrader: (1)

Good to listen to BGH. When you replaced the carrier shims did you make sure they went back in the same sides they came out of? I got mine swapped and it was way too tight. Mine is 9 bolt.

excessiveego

changed carrier bearings, couldnt reuse factory carrier shims, wouldnt even come close to going back together

Base91

iTrader: (1)

You only need to reach a tooth on the ring to measure. .005 seems a little tight. I used a carrier from another axle and the original shims worked perfectly. I'm surprised new bearings would be that much different. Are you using a crush sleeve or the solid spacer?

excessiveego

Crush sleeve and i need to reach the pinion to properly measure pinion depth

big gear head

I don't understand why you need to reach the pinion. The pinion depth can be more accurately checked by reading the contact pattern. All you need to measure is backlash and bearing preload.

excessiveego

I understand that. But "manufacturer procedure" is to set the pinion depth based on the number engraved on the pinion. I realize that is only to get you close during initial setup.

excessiveego

well I cant get the other pictures to upload but here is my new pattern. Had a .010 shim on the pinion before, went down to a .007 and set backlash to .007 (spec is .007-.009) Looks better but I get the feeling that I did too much and now it is too close to the face of the tooth.

Base91

iTrader: (1)

What does the other side look like?

big gear head

The coast side doesn't look bad. What does the drive side look like?

excessiveego

finally got the other one to upload

big gear head

That's not a typical pattern, but it is much better than what you had before. All I can recommend is trying the backlash at .009 and see how it looks. Sometimes a gear just won't give a typical pattern and you have to settle for the best that you can get. The coast side does look pretty good, so you might have to go by that. I't also a good idea to check the pattern in more than one place around the ring gear.

Just in case the person who sold you these gears didn't tell you, almost all of the 3.70 gears for the 9 bolt will make noise. No matter how well they are set up they still make noise, usually between 50 to 60 MPH.

excessiveego

I think it made it worse

big gear head

I don't know that it's worse. It's hard to tell with the way the light is hitting it in the picture. The shadow makes it hard to see what the pattern actually looks like.

Here is something that you should try to make a more clear pattern. If you have the pinion bearing preload set to about 20 inch pounds then take an axle and stick it in the differential and use the axle to turn everything when doing a pattern check. The resistance in the pinion bearings puts plenty of pressure on the gears so that the compound is wiped away, and you can use the axle to make longer, smoother turns so that there are no chatter marks in the pattern. Turn it in both directions several times.

excessiveego

to me the coast side looks closer to the face, thats why I said it looks worse

excessiveego

here is a better picture of the drive side, much clearer pattern using the axle to turn it, thanks for that tip.

big gear head

Looks pretty good to me. What does the coast side look like?

excessiveego

coast side

big gear head

I don't think you are going to get it much better than that. I think I would run it like it is.

excessiveego

thats what I will do then. Thank you very much for all the help and patience.

big gear head

You are welcome. I hope it's quiet.