I switched from 3.73 to 4.10 and since I have 4WD, I had to swap both sets. As such, I have a front and rear set for sale. The front is 8.25 IFS and the rear is 8.5 or 8.6. This is for Ring and Pinion ONLY. You need to supply fluids and bearings, etc, etc. This set is OEM GM so it will be quieter than the Richmond Gears or other gears that go in. Asking $150 for the two sets plus shipping. I am open to REASONABLE offers before ebaying the sets.
The reason for the swap was because I needed to tow a bigger payload and I wanted the safety margin. The gears came out with no issues. As far as I can see, there has been no abnormal wear issues and the gear oil was not burnt and no metal shavings, etc, etc.
50000 miles on the gears.