Cummins Turbo Diesel Relaibility

In your opinion which is the more relaiable combination

1- Cummins Turbo Diesel with Chrysler Transmission ( or is it Detroit Diesel??).

2- GM Duramax ( Basically ISUZU) with Allison Transmission.

Trying to decide on a work vehicle that will be towing every day for about 3 days a week.

You’re probably fine with either one. The Cummins name certainly has more cache in the used market, which may be an issue if resale value is a factor. I know a lot of people who grouse about the servicablity of the Cummins engine, but usually its in relation to how much more cramped the engine compartment got when they switched over to the newer body style in the early 90’s. It could very well be that the Duramax is just as bad.

I’d say the transmission would be a toss-up too. I’d generally say GM over Chrysler, but who knows who actually makes them these days. The safe way to go would be a manual transmission.

The GM transmission is NOT an Allison transmission by any means. It’s a transmission built by Allison per GM specs.

Have you considered the F350 with the Navistar diesel?


Siemens provides the Fuel injection for the Navstar engine which is built by international. I have worked on manufacturing of components for the fuel injection for this engine and the design doesnt inspire confidence. They are not really designed with manufacturing in mind. Hence my reservations.

I definitely agree with manual transmission thats the only way to go.

When I used to drive a truck I was not happy with the reliability of my Volvo/Cummins truck. One problem was that Volvo used some non-cummins parts in a Cummins system. I had a burned out light bulb in my idle control system. Cummins said it was a Volvo problem and Volvo said it was a Cummins problem. For this reason I would prefer the GM Duramax. GM makes the truck and the engine, so there should be fewer of these problems. With the Cummins/Chrysler combo you have one company making the engine and another company making the truck. This is a bad idea. Cummins is not known for reliability. Cummins is known for inexpensive repairs in comparison to some of the more reliable engines like Caterpillar.

I think the Mopar boys have gotten their act together on the transmission thing, lately. Powerplant for powerplant, I’d peg them about the same. A lot of loyalists on each side will sling mud, but I think they have both proven themselves.

I would be less concerned about the motor and more about what kind of deal you can get on the truck. I haven’t been paying attention to that market for a while, but when last I left, Chevrolet was holding its resale value quite a bit better than Dodge. Though Dodge tends to come in quite a bit better on initial price, so it’s a little bit of a crap shoot.

I do agree with Tester, you might want to check out the F-series, it has the 6.4, which is quite a beast or so I’m told.

I own a Dodge Dually with the 5.9 Cummins and I love it. The Cummins has 200k plus on it and I keep it serviced religiously. The only thing I have replaced on it other than normal wear items like hoses and filters were the water pump and the fuel shutdown solenoid. Its a work horse and has never left me stranded. Its louder than the Ford and GM but hey, its a diesel. The transmissions have changed greatly over the years. Chrysler has made great improvements in it and has worked out most all of the bugs. I would highly recommend one. The Duramax is a stout motor, I dont have any personal experience with one but I have heard good and bad with it mostly with fuel related items. The Allison transmission is an awesome transmission, The only downfall of the Allison is the cost to repair. An overhaul kit alone lists for $1460.00, a pump $800.00 and god help you if you burn up a planetary gearset…ONE of the planets will run you a cool $2100.00 I build quite a few of these every month, probably an average of 7 or 8 every month. I have a flat bed tow truck made by International with the Navistar motor in it. No complaints about the reliability, it just seems that its not as strong as the Cummins, to me… My vote is definately with the Dodge.


Make sure you run the gears up to higher speeds. The diesel would rather wind up than be lugged.