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Been getting help from a buddy over the phone, but wanted to throw it to everyone else too.
Does this pattern look OK? First time doing gears and I think I might have it, but wanted to make sure before I press the bearing on the pinion.
Pinion Shim is .032 and BL is .005
I know the BL is a little tight, but I could not get it in the .006-.009 range. The thinnest shim I had took it from .005 to .010.
To me, I know the drive side can be a little towards the toe, so that looks fine and my coast side looks like it is centered between toe/heel and root/crown.
1. What is the ratio?
2. This looks like a 5 cut gear. What is the brand?
Backlash Tip:
You will not always have shim sizes that allow you to make exact moves. In otherwords, if you need to move the differential 0.002”, you may not be able to build a shim pack set that allows you to move that exact amount. Also, a change in shim thickness does not yield the same change in backlash. Assuming you are using a 5 cut gear which requires a backlash of 0.006” – 0.010”, I would suggest that you build a shim pack for the passenger side (opposite ring gear) that is 0.003” thicker. If those shims are already in there really tight, then I would make the ring gear side shim pack thinner by 0.002” – 0.003”, and then make the opposite-ring gear shim pack thicker by that same amount. The numbers don’t have to be exact. The goal is to get into the right backlash range while maintaining carrier bearing preload.
Also, you need to mix a little more oil in the gear paint.
When you run the pattern, make sure the pinion is tight enough such that you get about one free spin out of it. Install the carrier, paint the teeth, and rotating the pinion until the painted teeth are meshed. Next, put a ¾” wrench on one of the ring gear bolts. Use one hand to hold the wrench on the ring gear bolt and the other to move the wrench up and down. Do this with gusto. This method will yield a nice pattern. This method is one way of running the pattern. However you do it, you want to ensure you are putting enough force into the assembly to make a good pattern.
1. What is the ratio?
2. This looks like a 5 cut gear. What is the brand?
Backlash Tip:
You will not always have shim sizes that allow you to make exact moves. In otherwords, if you need to move the differential 0.002”, you may not be able to build a shim pack set that allows you to move that exact amount. Also, a change in shim thickness does not yield the same change in backlash. Assuming you are using a 5 cut gear which requires a backlash of 0.006” – 0.010”, I would suggest that you build a shim pack for the passenger side (opposite ring gear) that is 0.003” thicker. If those shims are already in there really tight, then I would make the ring gear side shim pack thinner by 0.002” – 0.003”, and then make the opposite-ring gear shim pack thicker by that same amount. The numbers don’t have to be exact. The goal is to get into the right backlash range while maintaining carrier bearing preload.
Also, you need to mix a little more oil in the gear paint.
When you run the pattern, make sure the pinion is tight enough such that you get 1.5 – 2 free spins out of it. Install the carrier, paint the teeth, and rotating the pinion until the painted teeth are meshed. Next, put a ¾” wrench on one of the ring gear bolts. Use one hand to hold the wrench on the ring gear bolt and the other to move the wrench up and down. Do this with gusto. This method will yield a nice pattern. This method is one way of running the pattern. However you do it, you want to ensure you are putting enough force into the assembly to make a good pattern.
Bryan, thanks man. Appreciate the thorough write up.
This is a Motive performance 4.10 gear set for a GM 8.5 part number G885410. I believe that is a 5 cut.
Sounds like it would be good to buy a shim kit that has smaller increments. The shims that come with the Motive master rebuild didn't go into the thousandths of an inch for the carrier. Do you agree?
How do you measure carrier bearing preload? I don't think I have seen that in any guides. That was one thing I was curious about. How do I know how many shims is right on each side of the carrier if I get the BL set correctly.
Yeah, this was like my 5th or 6th time taking the carrier and pinion out, so I might have gotten lazy on the oil/marking mixture. All my other patterns were making solid markings.
One way that helped in measuring BL without the pinion moving is I just tightened the pinion nut up all the way without a crush sleeve and then the pinion wouldn't move so I could move the ring without the pinion moving. Of course, I loosened this when I was ready to make my pattern. If I didn't however, would that have caused the pattern here to not show as well?
You are in luck. GM 8.5/8.6 5 cut 4.10s have always set up with a 0.035"-0.037" pinion shim for me. Start with that.
The motive kit should have 0.020", 0.015", 0.012", 0.010", 0.008" shims, or thereabouts. You won't have individual 0.001" shims as those would be paper thin and would not work.
Tighten the pinion without a crush sleeve until you get about 1 free turn out of it. This tightness helps give the drag needed to make the pattern.
When you install the carrier and tighten the bearing caps, do not immediately measure lash. You need to first grab the pinion and give it a few turns in both directions. Be abrupt when changing direction as this seats everything and your backlash readings are more true.
You are in luck. GM 8.5/8.6 5 cut 4.10s have always set up with a 0.035"-0.037" pinion shim for me. Start with that.
The motive kit should have 0.020", 0.015", 0.012", 0.010", 0.008" shims, or thereabouts. You won't have individual 0.001" shims as those would be paper thin and would not work.
Tighten the pinion without a crush sleeve until you get about 1 free turn out of it. This tightness helps give the drag needed to make the pattern.
When you install the carrier and tighten the bearing caps, do not immediately measure lash. You need to first grab the pinion and give it a few turns in both directions. Be abrupt when changing direction as this seats everything and your backlash readings are more true.
Thanks, that helps. I will go back tonight and start over on pinion depth and carrier shims. I think I just need to get the right combination of shims for the carrier to make it work.
Based on my pics, were you thinking I am too shallow on the pinion or too deep?
1. Measure the thickness of your old crush sleeve.
2. Build spacer to match said thickness.
3. Install pinion and spacer along with the outer set-up bearing.
4. Using the OLD PINION NUT, tighten to 250 lb. ft.
5. Using an in. lb. beam style torque wrench, check bearing drag.
6. Adjust spacer thickness in small increments until you get 14 - 19 in. lbs. of drag/preload.
7. Remove pinion and install new outer bearing and oil seal.
8. Using the new pinion nut with thread locker, install pinion, and torque nut to 250 ft. lb.
For step 5, you will need to pay attention to the reading WHILE THE PINION IS TURNING.
01-15-2018, 11:42 PM
Gear pattern look right?
