Pinion preload
10-10-2016, 09:01 PM
#1
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Pinion preload I am eliminating the crush sleeve on the pinion gear by installing a Raetech spacer. I do not have the carrier removed but the axles are. The outer pinion bearing is new. When setting it up, the different rotational torque I achieved with different shim combinations were the following:
7 in/lb
20 in/lb
45 in/lb
Which would be the best choice? Again, carrier is installed, axles removed, outer bearing is new.
7 in/lb
20 in/lb
45 in/lb
Which would be the best choice? Again, carrier is installed, axles removed, outer bearing is new.
10-11-2016, 11:48 AM
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20 is what I was more comfortable with. 7 seems a bit loose with the carrier installed. 45 is pretty tight and hard to turn. There is only 0.002" difference in shim thickness between each configuration I tried. Nice not to deal with the crush sleeve anymore, just torque the pinion nut to 125 ft/lb and done.
10-11-2016, 02:17 PM
#5
i think you need to remove the carrier, and measure just the rotational torque of the pinion bearing first.
for 7" GM gear sets the value for new pinion bearings is 10-15 inch pounds,
{for 8" is 15-20 inch pounds, for 10" is 20-25, and 11" is 25-40}
once you have the preload value for just the pinion, then you install the carrier/differential (without the axles) with necessary shims to add preload to that.
Now you re-measure your pinion rotational torque, it will be higher.
[this new total torque minus already measured pinion torque] x gear ratio = the preload of just the carrier which should be within some range.
from your description all you know is 20 inch pounds total,
but that could mean your pinion bearing is tight and the carrier bearings are loose or vice versa.
you want to know and be sure, because if the carrier bearings don't have the proper preload then the ring gear will deflect under load and that's bad.
for 7" GM gear sets the value for new pinion bearings is 10-15 inch pounds,
{for 8" is 15-20 inch pounds, for 10" is 20-25, and 11" is 25-40}
once you have the preload value for just the pinion, then you install the carrier/differential (without the axles) with necessary shims to add preload to that.
Now you re-measure your pinion rotational torque, it will be higher.
[this new total torque minus already measured pinion torque] x gear ratio = the preload of just the carrier which should be within some range.
from your description all you know is 20 inch pounds total,
but that could mean your pinion bearing is tight and the carrier bearings are loose or vice versa.
you want to know and be sure, because if the carrier bearings don't have the proper preload then the ring gear will deflect under load and that's bad.
10-11-2016, 05:06 PM
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Yeah, I really don't want to mess with the carrier. It's never been touched and the gears look great with 230,000 miles. It's now a daily driver only and does not see any abuse.