6.7 Cummins vs 6.6 Duramax

[SoonerWing03]

As someone who knows next to nothing about Diesel engines, I am trying to figure out the strengths and weaknesses of these to. Any opinions would be appreciated.

[ShinerBock]

If I am not mistaken, the 6.4L used a Siemens K16 VDO HPFP, not a CP4.

[skidooman93]

I can reply to this with a little different perspective. For a living I am a self employed mechanical inspector. If it has wheels and drives I’ve probably done a mechanical inspection on it. I’m hired by insurance companies, extended warranty companies, manufacturers, lawyers, and others. From my experience both are good engines. However of the 3 main light duty truck Diesel engines (ford 6.7, Cummins 6.7, duramax 6.6). The duramax is the least dependable. All generations of the duramax 6.6 suffer head bolt stretching that leads to head gasket failure. This is especially true in cold climates. Head studs seem to take care of the problem but that’s after 20 hrs of work and $2500 in parts. The cummins seem to have the least trouble of all 3. And since the earlier cp4 pump disaster in 6.4 fords. It has tuned out to be a pretty reliable pump. The Alison tranny is better than the 68RFE however if both engines are left with stock power levels the 68 has been a strong transmission too.

[ksss]

Bionic Man wrote:

4x4ord wrote:
I would expect when the newly designed 2020 Gms are available you should be able to get a very good deal on a new 2019.

Maybe. Maybe not. I haven’t seen a lot of love for that new design from anyone - be it automotive press or owners forums.

The looks on the Chevy are …..causing some discussion, the looks on the GMC are getting very good reviews. The interiors are functional and clean but not the level of bling you see in the top shelf Ram. What will save the Chevy is the performance. With what appears segment leading tow ratings, limited nanny input and a lot of tow technology, it wont be hard for a serious buyer who uses an HD as an HD to jump to the 2020. There will be those that like the '19 styling and are not tempted by what the 2020 brings to the table. However I don't see GM struggling to sell the 2020. If they hadn't stepped up their HD game, I would agree.

[4x4ord]

CampinginCanada wrote:
The leftover 2018 ram diesels here are selling for 20k off before negotiations. And with the strong US dollar, I’m surprised more people aren’t coming up here to buy them.

In order for an American to buy a truck up here in Canada he would have to buy slightly used. An American can buy one used vehicle per year and import it into the USA very easily if he drives it across the border himself (there is a little bit of paper work that has to reach the border 3 days prior to the vehicle..... a recall clearance letter). Warranty can be an issue. Ford warranty transfers. GM warranty transfers but there is a period of time it is interrupted for (I think maybe 3 months but I don't remember). Ram warranty does not transfer.

[CampinginCanada]

The leftover 2018 ram diesels here are selling for 20k off before negotiations. And with the strong US dollar, I’m surprised more people aren’t coming up here to buy them.

[Bionic_Man]

4x4ord wrote:
I would expect when the newly designed 2020 Gms are available you should be able to get a very good deal on a new 2019.

Maybe. Maybe not. I haven’t seen a lot of love for that new design from anyone - be it automotive press or owners forums.

[4x4ord]

I would expect when the newly designed 2020 Gms are available you should be able to get a very good deal on a new 2019.

[SoonerWing03]

Most likely a new 2019... unless I can find a new 2018 still laying around. Maybe I can find a demo unit that I like. That would probably be ideal.

[4x4ord]

Are you buying new? 2020 or 2019?

[SoonerWing03]

I want to thank you all for your thoughts and comments. Now it’s time to try to get the best deal that I can 🙂

[whjco]

allen8106 wrote:
I've had Chevy, Dodges and GMC trucks throughout my life and the two Dodges I had, 2000 and 2002, both had transmission failures. I vowed after the second one to never own a Dodge again. Not trying to start an argument about which is better just providing my experience.

I never did like Dodge trucks and they had their fair share of problems during that time period. How many times have we seen the comment "unfortunately, it's a great Cummins engine with a Dodge wrapped around it". However, about 2010 major upgrades were made to Ram trucks and now they're one of the best engineered and most reliable trucks on the road. Four years ago I bought a 2015 Ram 2500 CTD and it's absolutely the best truck I've ever owned. That includes five Suburbans, a 7.3 diesel Excursion, two Ford E250 vans and a Ford E350 van with a 7.3 that I ordered new.

Frankly, it seems that we're at the point where each of the "big three" build really great HD pickup trucks and I'd be happy with the offering of any of them. Anymore, it comes down to the price and the quality and reliability of the dealership service as to which one is the best truck.

[allen8106]

I've had Chevy, Dodges and GMC trucks throughout my life and the two Dodges I had, 2000 and 2002, both had transmission failures. I vowed after the second one to never own a Dodge again. Not trying to start an argument about which is better just providing my experience.

[rvshrinker]

i went with Ram/Cummins and have loved it. i chose Ram because i liked the look, the cummins/aisin combo had a reputation for durability, and on the highway most hotshot drivers were driving Rams. they love the durability of these engines and the ease of working on them. i pull a loaded tt uphill in 100 degree heat like it is nothing.

[whjco]

I have a 2015 Ram 2500 with a 6.7 Cummins and love it. Our bus company also has a Freighliner bus with a 6.7 Cummins and several more with the Duramax engine. Frankly, both are excellent engines and very reliable. I'd go with the best price/dealer service option.

[ib516]

In the end, when the 3 truck brands with diesel engines are hitched to a heavy trailer and asked to tow a huge load up a steep, 8 mile long hill, they all are within about 30 seconds of each other arriving at the top. Buy the one you like best. I really think they are all good, just with different personalities.

There was a time when Ford and GM used junk diesel engines, but those days have passed IMO.