6.7 Cummins vs 6.6 Duramax

Having an 07 Dmax, I like it. There are some quirky things about it, but I don't know if it has had more problems than my friends' Dodges.

What is bad is that the water pump tends to fail punctually at 160K miles, but it fails slowly giving you lots of warning (leaking) giving you time to get it into the shop.

The other weird problem on the 3/4 ton is running it at high altitude, load, and heat. There can be an occassional problem where the engine will flip into limp mode because the fuel hose can get soft and start to collaspe starving the engine for fuel. Let it cool for a couple of hours and the problem will self fix and the shop won't be able to locate the problem!

Another problem on the 3/4 ton is the primer on the fuel filter. Every few years the rings start to leak and you will need to replace them. The new assy cost about $900, the rings cost $13 and take an hour to replace. Fairly easy to do.

The solenoids on the 4 wheel drive system can get weak. Those are about $250 in parts, and if you have a lift can be replaced in about 1 or 2.

Beyond that it runs pretty darn good, and better than my friend's younger Powerstroke. (leaky injector bent a piston rod).

My mechanic tells me that today he could get me what I paid for it used years ago because some people want that LBZ engine. My mechanic also says I have another 250K-300K miles left in it.

What I will say is that there is nothing like 4WD and a turbocharged diesel for towing, even though I could probably pull the current RV with a gasser.

ShinerBock wrote:
Is it the same people that told you that the 2019 Cummins was not going to have an EGR? If so then I would stop listening to them.

I recall it was a special cummins lady giving a tour. The way I understand this went down is she was winking at him and blowing kisses in his ear while whispering that the CP4.2 was coming, but somehow that got translated to downstream EGR, crazy HP and torque increase and the "new green deal" fuel economy performance recognition award.

Crazy stuff...

Is it the same people that told you that the 2019 Cummins was not going to have an EGR? If so then I would stop listening to them.

If something like a valve body is broke and did not cause clutch or any other damage, then we replace the valve body, not the whole transmission. The only time the whole transmission is replaced if is beyond repair or the cost to repair is more than a new one. In that case the bad one gets sent back to Aisin (IF that is where we purchased the new transmission) as a core so they can re-use the case and other parts. In many cases they just want the core back so other re-builders don't get their hands on them like Revmax and Suncoast who both have built versions of the Aisin.

Going by reports and from a parts manager I know.

Cummins12V98 wrote:

ShinerBock wrote:
Speaking of Aisin, we just had two in our mobile service truck 5500s replaced at one of our Ohio dealerships. Failed line pressure solenoid from what my corporate fleet manager said.

Very few issues with the AISIN. If there is an issue they simply replace and send to Factory.

I am not sure where you are getting this info from, but that is not what we do at our 120 dealerships. There are also more than "very few" issues in the medium duty trucks that we sell/service with Aisin transmissions. I hate to burst your bubble because I know how adamant your are about whatever you own being the best in the world.

Cummins12V98 wrote:

FishOnOne wrote:

Cummins12V98 wrote:
Ok Skid

What about the true Medium Duty AISIN?

You mean the one used in the Nissan Titan...

No silly!

LOL... Someone had to ask the question. :B

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

My bad, yes the 6.4 ford used the K16 pump. Which was half the reason the disaster the 6.4 turned out to be. The other half were the injectors

The late model 16-present cp4 pumps have been much better I haven't done an inspection on a 6.7 ford with a failed pump in a awhile.

As far as trannies go. In 12 years of inspecting I've looked at 1 Alison. Then a couple dozen torque shifts (until recently) and 68 RFE's. What saves the Alison is they shut themselves down and go into limp in really easy before stuff gets torn up. VS the Torque Shift that goes and goes until it grenades. The 68's are some where in between. I have never looked at an Aisan but they aren't that terribly common so I cant comment much on them. The most recent 6 speed torque shifts seem to have a problem with the rear planetary. I have seen half a dozen school buses and as super duties that have torn up trans because of a rear planetary failure.

In my opinion I wouldn't worry about the transmission in any of the GM, Ford, or Ram 2500-3500 trucks as long as the engine is kept at its stock power levels.

FishOnOne wrote:

Cummins12V98 wrote:
Ok Skid

What about the true Medium Duty AISIN?

You mean the one used in the Nissan Titan...

No silly!

ShinerBock wrote:
Speaking of Aisin, we just had two in our mobile service truck 5500s replaced at one of our Ohio dealerships. Failed line pressure solenoid from what my corporate fleet manager said.

Very few issues with the AISIN. If there is an issue they simply replace and send to Factory.

ShinerBock wrote:
Speaking of Aisin, we just had two replaced in our mobile service truck 5500s replaced at one of our Ohio dealerships. Failed line pressure solenoid from what my corporate fleet manager said.

Yikes. Any idea of the cost?