Duramax break-in

[beach buddy]

Just now I took delivery of a 2003 GMC Duramax/Allison 3500. Dealer told me break-in is done at the factory and I could start hauling today.

Dos anyone know anything about this?

Thanks for any information.

[Colorado Kid]

That's not what the book says.

I could repeat it for you here, but I'd rather not. The engine WAS run at the factory, but not long enough to achieve a proper break in, and the transmision and axle have not been "run" at all.

The fool at the dealership probably believes what he says, otherwise he'd feel bad about letting folks beat the #$%^ out of brand new trucks on test drives. I ordered mine, and I was there when it got off the truck at the dealership. They didn't let me drive it off the truck, but they did know that it better be treated gently or we were going through the order process again!

[mackey_62]

I'll second that. YOU have to break-in.
Now you know what to expect from your dealer, looks like you got one of the good ones :rolleyes:

Do a search here for "break in", you'll find everything you need to know and more. Also, there was link posted somewhere from a Ford page about diesel break-in, worth reading.

Good luck, and oh yeah, welcome.

[NutNbutGMC]

^...Drive it like you borrowed it from your brother-in-law. It will perform through it's life-cycle, as to how you break it in. Treat it like a sissy and it will run that way. GOUGE ON IT HARD, from day one. However, don't expect more than 97 MPH and don't get mad when a mini-van smokes your arss.... Learn how to block them.

[ 10-04-2002: Message edited by: NutNbutGMC ]</p>

[MudNurI]

LOL nutn!

Sounds like how we broke ours in. Never tow with it, and not sure if I would tow a huge trailer with 3 or 4 miles on it, but we didn't keep it under 55. Heck, we had the truck for 4 days before we decided if we were going to keep it, needless to say, we drove it like we were going to return it! received it with 7 miles on it, kept it for 4 days- put 800 miles on it during those 4 days- and never looked back. No major problems to report from this not okay break in procedure- but then again, were runnign synthetic. :D

Brandy

[SoCalDMAX]

And don't forget to scrape the econobox guts off the grill once in a while, it tends to block airflow over the intercooler if you let too many of them build up... ;)

Regards, Steve

[Timberline]

I agree with NutNbutGMC!
I babied mine for the first 100 miles Then I put the trailer on her and have driven like I stole it ever since. I don't abuse it but it's not babied either.

[shft22]

I picked up mine at a dealer 250 miles away from home, it had 5 miles on it. I drove her home and kept her over 75 all the way, now after a year and 23k miles, I'm still keeping her over 75 most of the times, and she has not complained. Don

[3TV]

This link will describe the actual engine break-in proceedure that each and every Duramax engine is put through.

http://www.62-65-dieselpage.com/duramax/DMAX.pdf

It is way down on page six, so you have to scroll down to find it.

Basically they artificially warm up the engine for two minutes, and then ramp it up to its maximum rated load, and run it at maximum load for six straight minutes, then cool it down for two more minutes. That doesn't mean maximum RPM for six minutes, but it does mean MAXIMUM LOAD!

With that in mind I do not think it makes beans difference what the owners manual says about not exceeding a certain mph, varying your speed, etc. I did not run my truck at maximum load for six straight minutes after I got it home from the dealership for the first time, but Isuzu already had. So they worked it harder than I did, and any "break-in" I did in the first few days of ownership would have been a moot point.

The only thing I did with my Duramax Chevy was take a nice long scenic drive through Monument Valley, Grand Canyon National Park, Four Corners, and back home again, for an 800 mile cruise in the first two days of ownership. When I got home I changed all of the fluids and filters, installed a Juice 4.0, and went drag racing :D .

I figure its broke in just fine.

3TV

[deerhunter7]

Beach Buddy A good link for you is
Http://thedieselstop.com/contents/getitems.php3?
Breaking%20in%20a%20Diesel%20Engine This use to
be the Ford Diesel Page . Now called The Diesel
Stop . To run it like you stole it I don't think
is the best advice. Read article and make your
own decission. One thing Jay the author doesn't
cover is that your breaking in the engine also includes stress relief . One of the reasons for the variable speeds. Temps rise and fall. As a blacksmith/welder for a utility Co I have had several classes on this subject,alot of it over my head . But basically every cast , machined or
welded part has stress , kind of the nature of the beast. Simple example , any one who has sharpened a chiesel and seen a little blue
coloring in the end and first time using it you
get a chip out of it. First thing you think is
cheap metal,{good be } but most likely when you
seen the blue you heated the metal up and took
the temper out and now you have strong but very
brittle metal. Tempering is actually sofening the
metal not hardening like most people believe. If this chiesel was made of the standard material Most of are impact bits are you would simply heat
the tip to 350 degrees and let air cool .You keep the toughness but take out the brittleness.
In away thats what you are doing when you break in
your engine . A metallurgist good explain this
process much better and detail that would loose
most of us. But if any thing theres alot more to properly breaking in an engine than the eye can see.. ;)

[mackin]

Drive it like your in "HOT PURSUIT" I had to, and it doesn't use a drop of earl.......
Fluctuate your speed, keep it off the rev limiter, avoid hole shots if possible.....

tongue.gif

MAC

[chevmeister]

Break in is overrated. Thats why you have a waranty. If you bought it to tow then hook it up. Thats what its built for. My break in consisted of 200 miles of empty driving from friday night when I got it till monday morning when I had to hook it up. But then I was towing 10k with a 1500 gasser everyday. Untill I overhated it, but thats another story.

[White Knight]

One thing not addressed in the messages on proper "break-in" is the procedure recommended for the locker rear end. I copied this from an earlier post. I would think it would be prudent to take the manufacturer's recommendations on break in, but it's your truck. ENJOY!!

Sam

From Mr. Ralph Holmquist of Eaton, the maker of the locking differential:"The maintenance schedule for the rear axle was developed by American Axle & Manufacturing and GM truck based on multiple tests. The Eaton locker does not require additional maintenance nor does it add heat to the lube. The lube will darken due to the carbon wear on the clutch surfaces, much the same as a disc brake pad & rotor. This does not damage axle components such as seals or bearings. However, a new axle can produce excessive temperatures (plus 350 degrees F) due to the ring & pinion breaking in that will break the lube additives down. Avoid high loads, trailer towing and high speed extended driving during the initial break in of the vehicle. After the break in period axle temps will level at a much lower figure. Lube changes are a good idea because the additives are replenished and contaminates such as casting sand are eliminated. The axle is filled at the factory with a synthetic 75w90 GL5 rating made by Texaco under part # 2276.The GM service # is 12378261. This is the only lube we have done extensive testing with to insure locker compatibility. The only negative to using one of these other lubes is an increased potential for clutch chatter. This really doesn't hurt anything and can be corrected by changing the lube. I noticed in the latest GM owners manual the term "or equivalent" when referring to the lube specification. Look for a GL5 rating on the bottle to make sure the ring & pinion, seals & bearings are protected. Limited slip additive is not needed. "The following information outlines the type of rear axle lubrication utilized in GM Truck axles. I. Fluid TypeII. The 1500, 2500 and 3500 GMT 800 Trucks utilize SAE 75W-90 Synthetic Axle Lubricant. The GM part number is 12378261 and the specification is 9986115.

[MAD-MAX]

Do not i REPEAT do not..pull up next to a foord or a doodge for the first couple of days so as to not burn the tires or hit the revlimiter while DRAG RACEING !!!! :D :D :D :eek:

[62dog]

I think White Knight pretty much hit the nail on the head. The main reason for a break in is the rear diff gears. The engine already gets all, or most of the attention from the factory.
These ductile cast iron ring and pinion gears are heat treated and lapped-in at the manufacturer. While lapping will get the contact pattern started it will be finished when it is in the truck, this is why varying speeds is improtant. If you generate too much heat, heavy loads or high speed, the will not temper properly. In other words they will become too soft and not last as long as the were designed to. So do change your gear oil.

[beach buddy]

Thanks guys for all your help, advice and comments.