alpine.adrenaline

What do I need to do to break in my new gears after going from 3.55 to 4.56? Do I need to pay attention to the pumpkin temps? How long until they're broken in?

xj101

good question i just swapped and drove it hahaha . and looked at my diff oil periodicly .

alpine.adrenaline

Figured I'm probably just being paranoid. Would a drain and refill be a good idea after, say, 1K miles?

xj101

yes ! . i was so paranoid at first i drained my diff oil through a cheeese cloth and then looked at it through a microscope to see if there was any metal debris. but it checked out fine havent had a problem since

Rock Toy

Yes, you should break in gears.

Drive 15-20 min. let cool down completely, do this multiple times, five or six, also no lugging or real hard acceleration for about 100 miles. Change differential fluid after 500 miles.

Off course listen for whines, and grinding, and look for leaks.

cruiser54

I'm stumped by this. How come a new vehicle can be delivered with new gears, freshly set up at the factory and then be driven with no caution or break-in whatsoever? And those diffs last in excess of 100K miles.

Not trying to be argumentative but it makes no sense to me. I was service manager at a Jeep dealership for 13 years. We never had an issue with gear break-in on brand new cars or any re-gears we did.

Rock Toy

Most new vehicles get there axles from major manufacturers that set up thousands of axles monthly. The axles are ran and checked before being shipped. As for your dealership never having a problem with the gears they set up you are lucky, a lot do have problems.

The information I stated wasn't my opinion I just stated what most gear companies state in their instructions. ( It is also more critical with high gear ratios. ) Heat build up in the gears can supposedly take the temper out of the ring & pinion unless broken in.