MK, this is hard to argue with, but I admit to following Randy's R&P break-in protocol to the letter after I had my 4.88s installed. I just figured I'd follow the old adage, "Better safe than sorry."

 

Understood, I was just lookin for something to argue about that day. That said, I hammered mine on the drive home, 55 miles from the shop at 80mph , no cool down. Maybe I was lucky,

 

Pulling the covers and inspecting isn't mandatory, but changing out the break-in gear oil sure is. My plugs were fuzzy with debris when I did my 500 mile diff service (post-gear installation) just yesterday.

 

Based on the visual in your avatar, yeah, I'd say you're lucky my man!

 

I had barely anything on mine, maybe my breakin procedure heat tempered them into super steel.

 

Thanks! Hopin to get some pics of her helping change the steering stabilizer on her TJ and my diff covers.

 

Well, I had my gears installed by the Dana engineering tech that is responsible for the the actual build process that created the JK gearset. I asked him that very Question. he said that the factory gearsets are impregnated with a dry lube that keeps the gears lubricated and cooler as they break in. because friction is the culprit to gear failure. the aftermarket gears are raw and have no such lube so they must be broken in easily so that they dont get to hot thus leading to excessive slop and that would lead to noisy gears. and ultimately failure.

 

impregnated with dry lube? How do they do that? Or are they just coated or do they heat temper it in or something?

 

I kind of wish the shop had just use cheap oil for the first refill. Guess it's cheap insurance and easy enough to do.

If they put Royal Purple diff oil in mine, what exactly are its weight/specs so I can go get more.

 

Ok, just finished my swap. Used Mobil 1 sythetic instead of Royal Purple (didn't carry it at Advance Auto). Piece of cake. There was only a slight film of metal slude on the drain plug. Mine by the way only had a flat magnet on the inside of the plug - nothing long like the pic in an earlier photo. Was done the whole process in 30 minutes. Most of the time was spent draining the fluid.

I was able to remove, sand and paint my muffler in between the front and rear drive drains. The muffler came off easy with the help of dish soap and a few screw drivers on the rubber hangers. Man it looks awesome. Used Krylon BBQ paint. 3 coats!