Rear end troubles.

[Swamppro]

My 98 converted 48 volt had full posi. Previous owner welded spider gears. This past week it popped during turn and lost posi and started grinding. Opened it up today and cleaned it up and got old loose slag out. Put it back together and runs perfect except whines when coasting. Any throttle and it's real quiet but the second you let off gas and no load rear end hums bad. What would that be? Thanks.

[Swan]

what gear oil did you use ?

[Swamppro]

80/90 regular gear lube. It hummed like this after it broke when I brought it home during the week. No grinding now just humming

[2016CTD]

The loose slag you got out probably worked it way into the bearings and worked itself around the gears causing some wear. Under load the gears and bearings are loaded no noise, coasting they are unloaded, thus causing you noise.
Just my .02 cents.

[Swamppro]

I saw some wear and a chipped gear. May run it some and see if it wears in. Will look at ordering gears soon though. Need to order a charger as well. Mine just crapped out. Rains it pours.