I got my 6.7 Cab and Chassis on Nov. 21 and now have over 12,000 miles on it. No problems at all. I have been posting in the 3rd gen areas. Guess I'll be posting here from now on.

All I can say is, don't be afraid of this engine. It pulls great, runs smooth and with the Aisin transmission, is a heck of a work truck. Don't get one without the exhaust brake, it is well worth the $.

 

How is the fuel economy on the 6.7 vrs. your old truck?

 

About 1 mpg less at the present time while towing. (10.3 vs 11.3) It's not broken in yet, it will be close to the other in another 15,000 miles. This truck weighs 1000 lbs more than my 03 and also has 4.10 gears vs 3.73's and a automatic transmission, (Aisin) vs a 6 speed stick. I don't believe there will be enough difference in fuel mileage to really matter doing what I do.

 

Considering you've got 4:10s with the new 6.7, it's not broken in yet, and it only gets 1 mpg less than the old 3:73 5.9? To me that is VERY impressive. I would think that by the time it is broken in, if it is getting about the same mileage as the old one, then the better economy of these new engines is as advertised. What I am really anxious to hear about though is these new 68 RFE autos.

 

What is an Aisin transmission?

 

It is japans answer to the allison. (I'm hopeing it kicks the crap out of the allison, but I'll wait to hear back from our first time buyers before I run out for one. I has to be better then the 47 and even the 48 re's)

 

They also built the transmission used in Jeep Cherokees for years. (behind the 4 litre) There are many early Cherokees running around still with the original Aisin AW4 transmission, and I have yet to see one fail. If the new unit is anywhere near as good as that one, it'll be a big success.

 

test drove one, the exhaust brake is GOLD! love the six speed. MUCH quieter in the interior aswell.

 

eb290,
I dont think anyone has asked this yet, but does the 6.7 motor sound like the 5.9? Not louder or quieter but could you tell it was a cummins without seeing it like our current 5.9's.

 

That's a good question. I'd like to know too.

 

You can tell it is a Cummins, it is different sounding than the 5.9, quieter, and smoother, but you can still tell it is a Cummins. Any doubt, put a load behind it and mash on it, then you will know for sure it is a Cummins.

 

Whats the GVWR & the GCWR ?

 

According to the book, it is 12,500 GVWR for the dual wheel model, and 23,000 for the GCVWR for what it is worth.

 

Does you cab and chassis have a 60 mph vibration? my dad jus got one and it does?

 

No, no vibration at all at any speed.