10 bolt gear setup help

[sweetk30]

my cousin is up for a visit and he swapped out his 2.73 gears open diff to a 4.10 and posi unit in his 2wd 10bolt .

every thing he said was good and in spec but after a 10 mile test drive its HOT to the touch and its now got a bit of backlash as you turn the pinion .

any thing to be checking ? ........ now its cooling off and then we will pull the cover and check .

 

[obijuank5]

Just needs a good old fashioned visual.
You can see if the pinion snout is cooler than the rest of the case its probably low preload allowing the carrier to shift causing bad wear which opens up the backlash and chews away material.

 

[sweetk30]

well temp gun showed our buddys truck rear after full warm at 115 *

this fresh new built rear with 20 miles maybe on it was 125* - 135* range . so knowing new bearings and gears build heat on running in i think its o.k.

we did find a new vibration tho at 65+ and looks like the pinion is a tad to high . going to play with that in the am .

 

[Blue85]

It is normal to get warm during break-in. I have no idea what you're seeing/hearing/etc, so definitely check it out, but the standard procedure is some shorter drive cycles to let it cool off. Also, are you sure you're feeling ring/pinion backlash as opposed to the spider gears? The new vibration could easily be the driveshaft or U-joints because it's going 50% faster now. That 50% more torque will be nice, though!

All new gear sets require a break-in period to prevent damage from overheating. After driving the first 15 or 20 miles it is best to let the differential cool before proceeding. We recommend at least 500 miles before towing. We also recommend towing for very short distances (less than 15 miles) and letting the differential cool before continuing during the first 45 towing miles. This may seem unnecessary but we have seen many differentials damaged from being loaded before the gear set was broken in.
Changing the gear oil after the first 500 miles is also recommend. This will remove any metal particles or phosphorus coating that has come from the new gear set.

 

[sweetk30]

she went from open diff to posi unit brand new .

u-joints are both new last time he was up and i even had the local shop re-balance the shaft as it was out a tiny bit .

today he played with pinion angle a little and is currently on a test drive .