Hey Guys, My Name is Brent Montgomery, I Live in Ligonier, IN and I just took delivery of my 2005 Duramax/Allison Truck. I am a Chevy Service Manager, but even at that I have found my self scatching my head and wondering on a few things.. I am so glad this forum is here i have gathered lots of info. from here like for example the normal oil press. (30 psi. warm) i looked at my guage tonight all the way to the store and back thinking man this is definatey different from my 6000 2500 hD, I dont claim to know everything, I'm just appreciative for every bit of knowledge i can pick up everyday.. Is there a break-in on these trucks and does it take a while for the allison to start feeling like its shifting normal... We Don't see alot of Duramax's in our Shop so i guess I am asking the Experts..LOL I was worried about the oil pressure, the way the Trans. shifted, and overall do these truck run a little higher RPM's at Hwy. Speeds ??:)

First off welcome....500 mile break in period before pulling a trailer seems to be a popular choice around here....the oil pressure you stated seems normal. Do a search for a time frame for first fluid changes....lots of reading there. Enjoy the new truck!

The 500 mile break-in is mainly for the rear end. The gears are supposed to be a tight fit and generate a lot of heat during the break-in. I did not baby mine during the 1st 1,000 mile, but I made sure I exercised the full rpm range and did not hold one rpm setting for long. My last unloaded highway milage was 20.3 doing around 65 mph with some sight seeing along the way.

I think the truck should hit about 2000 rpm as you approach 70 mph. I haven't been on the highway with mine in a few weeks and my memory is fading on the rpm's at 70. Hopefully, someone will correct the above if it is wrong. I have a srw with the stock 245 tires.

As far as the shifting of the Allison, I think it is just a matter of getting used to it. Things definately feel different compared to a gasser with a 4 speed.

I hope you become a regular poster and keep us updated as you hear things from the General. Best of luck with the new truck!

On Edit: 2000 RPM is at 67/68 miles per hour on mine.

:) Welcome pcwizard, The Diesel Gods :rolleyes: here made a recommendation to me when I first picked up my new baby. Change the oil with regular dino at 500,1500,and 3000 miles. This was supposed to help flush the new motor and keep her running in peak condition. I'm sure in your readings you'll learn that the diesel fuel we run is also pretty dirty even in it's refined state. Many run an extra fuel filter(with many different systems out there to choose from). I personally change my fuel filters at 10,000 miles just for peace of mind. You'll find yourself wanting to add lots of goodies. My personal preference is:

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Congrats again.....

Congratulations on your choice, you'll like it more every day.Recomend you lube it and check the differential level. GM is a little stingy both places once in the while. Even though you probaly have the new fuel filter on there I'd put a 2 micron prefilter on. Our diesel fuel isn't the cleanest in the world. Have a Nicktane set up on mine. There are others to.

Welcome aboard!!!! It took me a couple weeks to get used to my Ally from the GMC gasser V8. It will start shifting smoother and it "learns".

Congrats on your fine purchase! Good taste I might add. Don't know much about the break-in myself , listen to the experts here they'll tell you everything you need to know. Wish I had , ran a full tank of fuel through my D-max within the first few hours of owning the truck:eek: since then I've been good to it. Good luck and have lots of fun!!
-Matt