:D Hello to all, I am thrilled to have a new LLY for my Buisness. I cannot bear the thought of having to breakinas I have heard. I bought specifically for towing
compact Tractors, Bobcats Etc. I need to haul 10-15 Tons fo Gravel on seperate Trips of course in a 6-12 Dump trailer and am really wanting to Hook it
up per say tommorow. Is this Wise? I really enjoy the advice and expertise on this site which is of course was a tremendous help in my decision. Please help.
Thanks

I hooked mine up to a cattle trailer and hauled some cows 11 hours after the papers were signed. Nowhere near the weight you are talking about. I think the biggest deal is the rear end oil getting too hot with the gear break-in. If you are not hauling far with it and give it a chance to cool and change it ~500 miles. I don't see if there is a problem with that...but doesn't mean there isn't.

I personally would (and did) go ahead and tow.

):h Yeah give her a tug ... she can take it

Break her in the way she is going to be used. Just don't go crazy with the throttle. In my opinion a little extra cylinder pressure will help seal up the rings, just be careful about getting her too hot.

It woukld be nice to get a couple of 50 mile unoaded trips with enough cool time between for the rear diff gears to break in. From there, go for it.

I change my engione oil prior to 100 miles also to help flush out contaminants from assembly, and break in.

Drive it like you stole it. Just don't hold a steady speed at first.

I'd say tow to get those rings seated, but here is a repeat of a post I made several months back. I did follow the proceedure, and was SHOCKED at how hot that pumpkin got, even UNLOADED. Even when I did start pulling my 8K Toyhauler, it was hot after the fifteen mile segments. OTOH when I changed the grape juice out at 1k, the plug had hardly anything stuck to it...


Written by "Shawn Spickler" of Off-Road.com The greatest damage to a new gear set results when it has been run for ten minutes or more during the first 500 miles and the oil is very hot. Any heavy use or overloading while the oil is extremely hot will cause it to break down and allow irreversible damage to the ring & pinion. In order to make them run cooler and quieter, new gears are lapped at the factory. However, they are not lapped under the same pressures that driving creates. These loads generated while driving, force any microscopic high spots on the gear teeth back into the surface of the metal. This is called "work hardening". Work hardening is similar to forging in the way that it compresses the metal molecules into a very compact and hard formation. This can only be accomplished if the metal surfaces are lubricated and the gear temperature stays cool enough that the molecular structure does not change. If the temperature of the metal gets hot enough to change the molecular structure, it will soften the surface instead of hardening it. This may seem like a balancing act but it all happens easily & passively as long as the oil keeps the gear cool while it is breaking in. Some of the synthetic oils on the market today can help a gear set live longer. Theses oils will continue to lubricate at temperatures where many crude oils break down. Even with synthetic oils, you should still follow the procedure for
BREAKING IN A NEW GEAR SET:
After driving the first 15 to 20 miles it is best to stop and let the differential cool before proceeding. Keep the vehicle at speeds below 60 mph for the first 100 miles. You should put at least 500 miles on the new gear set before heavy use or towing. During the first 45 miles of towing it helps to go about 15 miles at a time before stopping to let the differential cool for 15 minutes before continuing. This is necessary because not all of the gear tooth is making contact until it is heavily loaded. When towing, the teeth flex to contact completely, and cause the previously unloaded portion of the teeth to touch and work harden. All of this may seem like paranoia, but it is very easy to damage the ring & pinion by overloading before the teeth are broken in. It is a good idea to change the gear oil after the first 500 miles in order to remove any metal particles or phosphorus coating that has come from the new gear set. This is cheap insurance and a good time to discover any problems before they grow to disastrous proportions.

Thats why I have run a rear differential cooler since I broke the first one in the 01.

I dont tow with any of my trucks until 1500 miles.

Thats why I have run a rear differential cooler since I broke the first one in the 01.

I dont tow with any of my trucks until 1500 miles.


And where are our pictures and parts list?

I'm going into the heavy towing business need one :D

Thanks and wow to the receptive response from all, I went ahead today towed and cannot figure how I got by on my older chevy 350's. It is a Joke how much better this thing did. I am so happy and will defiantely get my money's worth with this rig. I will be posting some Pics soon and am still hesitiant about Mods as of yet. I have heard about the fever when you start. I am right now going to go ahead put in bedliner. I want a X spray in but, the only place around that had been recommended has the Rhino. Hope no problems or feel free to advise me otherwise. I definately don't like the bridgestone tires that came with the deal. Any advise here would be appreciated as well. I always put on BF goodrich all Terraians on my other chevy's and liked them quite well . Again thanks to all.

oilbrnr, great post guy. :ro) I followed Shawn's advice to the letter when breaking my truck in. 500 miles, stop and go, first tow was short runs, etc. I even changed the axle fluid at 1500 miles. When I was having my tires rotated the other day they found my left rear axle seal is leaking, not really bad, fortunately it hasn't gotten to the brakes. Looks like a trip to the stealership is in my future. JJ :)

JJ, what level did you refill the diffy to? Thread level, or the controversial lower "revised" level?

I had it serviced at the dealer. I watched the guy do it, he filled it until it wouldn't hold anymore. Was that incorrect? JJ :confused:

Well, I'd have to search for it, and I'm amazed you haven't seen the threads, but starting with the 04.5's the factory started shipping the diffies with levels well below the fill plug. Many new owners complained and forced the dealer to fill it to capacity upon delievery. Come to find out, there is a bulletin out from GM stating that the correct level is, don't quote me on this, something like 1/4-1/2" below the threads.

Many have speculated that GM did this due to the high amount of axle seal failures they've had. Like yourself I'd guess. Now keep in mind that the owners manual still states the proper fill is to the threads (or just below).

Do a search, as I've forgotten more than I knew on this topic! ):h

Own my own business. Towed my bobcat, auger, 20 ft trailer and loaded the truck right away 25k no problems.

I towed with mine within the first couple days... No problems.. Hot rod the hell out of it the rest of the time.. Just got around to changing the diff oil the other day at 7100 miles and it didn't look too bad at all, not near what I expected from reading on here about the harsh break in. There was of course a little metal on the magnet but not near what I expected. Towed with it today hauling cattle and it reminded me again why I love it so much. It seems to do that every day...