[JTWard]

Does a remanufactured or a rebuilt differential using the same original gears need a break-in period ? I had a 'Dura-Grip' posi-traction differential install and it was done by a real good shop, but I hear a very slight hum @ 40 MPH?

Thank you !

 

[Crispyt]

I think "technically" there is a break in period even though its the same gears. This is because they may be sitting a slightly different clearences and now need to wear into that setting. On a rebuilt differental with a new gearset usually the break-in time is about 500 of light driving or light towing, then changing the fluid. I don't think you should hear any humming as a result of a gear not being broken in. A break-in is to allow the gears to make a wear pattern and fit to the proper mesh clearances and wear any metal spurs off from machining. You should never hear a humming sound as a result of a gearset not fully broken in from what i've been told. It's possable that the hum is just a tire that needs some air or its just from the tire treads normal sound.

Usually a humming noise is caused by an incorrectly installed ring and pinion gear that needs to be adjusted. Incorrect installation of the ring and pinion gear prevents proper tooth contact and can cause fast tooth wear and gear failure. The humming noise will eventrually start to sound like a growling noise when the wear increases. It can also from worn out bearings which need to be replaced as well.

 

[JTWard]

Thank you. It's good information !

 

[JTWard]

It's very helpful to be among others whom traveled this path. Like a boat, I was in the Navy and I know one thing, a boat is a big hole in the water you pursue to try to fill with money. Like wise, old trucks, I'm on a cause to try to turn a 25 year old pickup in very good condition into a 2015 Silverado, am I stupid. But that's how mind works, you do god, so I think good is great at the minimum. The best thing is to shut my mouth , get in and just drive it till it is as good as it is now, not 20 years ago, even though it was taker good care off. The biggest problem is me here !