redfishsc
Tired of fixing lousy engineering.
Good howdy all,
Could some of you experienced gents take a look at the gear pattern attached? Full backstory below, but in short, I think my pinion depth is too shallow. I think it needs a little more shim but I can't guess how much. Unfortunately I do not remember how much pinion shim is on this one, except that I am about 0.003 above what the factory shim was on the original 3.42 pinion.
Carrier and pinion bearings wore out (pitted) in my 1999 Suburban C1500 at about 206K miles. You could hearing singing (bearing whirrring noise) especially when coasting downhill with some drag on the motor.
Anyhow, being adventurous, and unwilling to spend the money the local shops wanted for new bearings only ($1500), I bought the tools needed and did it myself. Did a LOT of research.
Anyhow, I got it all put together, and got a "decent" pattern although I think my pinion shim is too small. You tell me, see the gear pattern below for drive/coast. Since I was occupying space at our cabinet shop (and, blocking the delivery trailers) I had to call "well enough" alone for now. I've put about 1000 miles on the gears so far, and they have a humming or "hooooo" sort of sound while driving (drive, or coast, and it gets quiet for a few seconds between drive/coast since there's no load on them). Sound ONLY happens between 40-55 mph. Any other speed is nearly silent.
Took a family Christmas trip in the Sub and put about 500 miles on it, it drove wonderfully and the gear noise is utterly silent above 55, and I drove 70 most of the way.
I would normally have taken the time to change the pinion shim, but with 3 kids and one more on the way, life circumstances ruled that out for the moment. I'm OK with having to buy a new gear set later if I've borked this set up, still cheaper than paying another shop. Just hassle.
Other than looking at the gear pattern, here's other info you may need to know.
Either way, I'm forced into the slow-train of getting this finally "perfect" because just today I noticed my intake gasket is leaking coolant behind the alternator. Gah.
That, and I still need to get the Speedo recalibrated. I'm using a dashboard GPS based "heads up" unit as my speedo, which is a nice upgrade either way.
Could some of you experienced gents take a look at the gear pattern attached? Full backstory below, but in short, I think my pinion depth is too shallow. I think it needs a little more shim but I can't guess how much. Unfortunately I do not remember how much pinion shim is on this one, except that I am about 0.003 above what the factory shim was on the original 3.42 pinion.
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Carrier and pinion bearings wore out (pitted) in my 1999 Suburban C1500 at about 206K miles. You could hearing singing (bearing whirrring noise) especially when coasting downhill with some drag on the motor.
Anyhow, being adventurous, and unwilling to spend the money the local shops wanted for new bearings only ($1500), I bought the tools needed and did it myself. Did a LOT of research.
Anyhow, I got it all put together, and got a "decent" pattern although I think my pinion shim is too small. You tell me, see the gear pattern below for drive/coast. Since I was occupying space at our cabinet shop (and, blocking the delivery trailers) I had to call "well enough" alone for now. I've put about 1000 miles on the gears so far, and they have a humming or "hooooo" sort of sound while driving (drive, or coast, and it gets quiet for a few seconds between drive/coast since there's no load on them). Sound ONLY happens between 40-55 mph. Any other speed is nearly silent.
Took a family Christmas trip in the Sub and put about 500 miles on it, it drove wonderfully and the gear noise is utterly silent above 55, and I drove 70 most of the way.
I would normally have taken the time to change the pinion shim, but with 3 kids and one more on the way, life circumstances ruled that out for the moment. I'm OK with having to buy a new gear set later if I've borked this set up, still cheaper than paying another shop. Just hassle.
Other than looking at the gear pattern, here's other info you may need to know.
- Gears-- 4:10 Motive (not the high perf.... which may be part of my problem)
- New Eaton Truetrac LS (which is fantastic, by the way)
- Bearings-- Koyo on pinion and carrier. Axle bearings were just fine, didn't swap.
- Pinion preload-- 15 in-lb, on a beam style wrench.
- Plenty of red locktite on carrier bearing bolts and on pinion nut
- Ring backlash--- 0.008-0.009 depending on which tooth... measured in about 6 places. Originally was 0.003 based on the manual I received, but opened it up to 0.008/9 thinking it was too tight... no change in noise.
- Rear housing is stock 8.5" 30 spline.
- Gear oil, dino Supertech 80W-90.
- Break-In-- First few trips limited to about 15 miles, with a good few hours cool down in between. Had to take a family trip at about 300 miles, checked differential heat frequently, yes it was hot but not unduly, I'd have to guess it was around 180-200 after a couple hours at 70mph.
- Cover--- Yukon finned aluminum cover I found for $60. Added about 1/2 quart extra to the capacity. No magnet, sadly.
Either way, I'm forced into the slow-train of getting this finally "perfect" because just today I noticed my intake gasket is leaking coolant behind the alternator. Gah.
That, and I still need to get the Speedo recalibrated. I'm using a dashboard GPS based "heads up" unit as my speedo, which is a nice upgrade either way.
