I went to the Cummins website and their only requirement for engine break-in for the engine is to keep the fluids topped off and use petrolium based oil for the first two changes.

They also reccomend not idling the engine for more than 5 minutes at a time and they also say to work the engine during break-in.

They don't say anything about keeping the speed under 55 for the first 500 miles, etc.

For the first 200 miles I kept the truck mostly at 50-60 MPH, a few times up to ~72 or so but mostly at the slower speeds.

From there up to 450 miles I've cruised at between 55 and 70+ on the highway.

I've varied the speeds widely from heavy traffic to highway cruising.

Now my question is:

If Cummins doesn't say anything about *NON*-towing speed restrictions during break-in, that means they're also saying it won't bother the engine to drive 60-70 during the first 500 miles.

This is driving without towing anything.

Do I have that right?

I don't know what Dodge recomends but Cummins doesn't say anything about taking it slow for the first 500 miles.

Check it out:

http://www.cummins.com/na/pages/en/products/dodgeram/faq/index.cfm

 

Best thing to do is work it hard right out of the box. Highway driving isn't really working the engine, but it won't hurt anything.

 

One thing to keep in mind is that Cummins specs breakin for the engine, but not the truck. I thought the 500mi of towing under 50mph was an AA&M suggestion for the axles. Something about them wearing in, or hardening, which makes a lot of heat...??

I remember reading similar suggestions for GM trucks, which also have AA&M axles.

 

its a truck drive it like u were going to a fire and hall all u can carry or all u can pull or it going to be a pig for ever

 

Steve has it right. The restrictions are for axle break in, not the mighty cummins.

 

I haven't done any towing yet.

Just did the 2nd fill up and now and have 556 miles on it.

That does sound correct, that the Cummins recommendation applies to the engine only so I'm not worried about the axles if I've done ~65-70 after 250 miles.

If they can handle heavy towing at 50 under 500 miles, I can most likely cruise faster with zero payload.

I love the truck, the sound is great!

DT.

 

All the other owners and mechanics I have talked to said "drive it like you intend to drive it and pull it like you intend to pull it" right out of the box.

 

newbie, you didn't buy the truck from Cummins, you bought it from DC. Who honors the warranty - even if the mighty Cummins bites the big one: DC. If the local CTD guy promises you your wildest dreams when it comes to warranty work - be wary; they don't have a dog in the fight when it comes to warranty.

You should have received an Owners Manual with the truck; you ought to read it. Even with 556 miles on it. You might surprise yourself and learn something from it.

Here's a little something I remember from my fond Navy days: RTFM (Read The Full Manual). That was the politically correct version. Yes, Sailors can read.