How long, generally, is a break-in period?

I was issued a new truck, a very nice one at that. So far I'm pleased with it, and I'm not trying to sound non-appriciative, but it does not run good at all. It's a W900 with an X15 565/1850 Cummins and an 18 speed, and won't get out of its own way on a hill. Everyone I talk to says it needs broke in, and once it gets past the break in period it will be an animal. Is this true? If so, how many miles does that generally take?

 

What gears are in the rears?

 

I'm not sure, they have to be the same as my old truck cause at 70 I'm running 1450, same as before

 

Great lol I thought I'd be passing everyone with a motor of that size

 

My experiences with break in periods with big diesel engines is fuel mileage and oil consumption. Performance is either there from the beginning or its not. It doesn’t usually get stronger power wise. Fuel mileage should get better and oil usage should go down to zero if break in goes proper.

With gas engines once we ran in the cam for 20 minutes it was full throttle fun at the track. Some guys I know never even spent the time running in the cam. It was assembly, fire up, set tune, race! Lol!

 

I swear I was reading on here the other day the exact same question and someone piped up and said that Cummins derates them until they hit a certain hour/mileage, then they open up.

No idea if there's truth in that or not, just something I "thought" I read on here.

 

If it was a CAT, one would say "drive it like you stole it" and that was a break in. But with a Cummin's Progressive Warranty they'll only pay for the first item that breaks. All the collateral damage downstream is on you (or the carrier). Always remember though, with a Cummins, you're actually getting 2 engines. No really.

 

I'm starting to think that's true because the truck does have a torque percentage gauge and the first day I drove it, it would only go up to 75%. Now it goes up to 80%. Also, it will build 25 lbs of boost pulling a hill, but makes 35 when the engine brake is on!! WTH lol

 

How does it perform at 1600 rpm?

 

Not great. To get it to run decent you have to keep it wound up to 17-1800. I'm not used to running a truck like that so I find it quite annoying