I'm doing my homework here on buying a new Megacab dually 4WD.

I have some questions about the new 6.7 trucks and transmissions.

Is the 6.7 with manual really rated at less power than the 6sp auto?

Would you buy a 6.7 or a leftover 5.9 with manual? My impression is the 5.9 can be turned up easily but not the 6.7 yet. I would not turn it up much as reliability is first priority.

How good a reputation does the 6sp auto have for durability? I hear the old 4sp auto was terrible. My neighbors '05 needed a converter by 17K miles. He did have it turned up a little.

I tow 10K lb trailer frequently. I assume the 6sp manual would be more bulletproof than any auto over the long haul, especially if slightly turned up.

What kind of rpm's will you turn with 6.7 manual vs 6sp auto? I hear the 6sp auto actually has 2 overdrives.

I'm new to the forum but have read almost all post that relate to the 6.7. I keep what I buy for a long time so I like to buy the right thing. I currently have the '95 F350 Crew PSD dually I bought new. 140K miles/no problems/auto/original batteries!/250hp/550lb with chip/EGTguage. Great truck, just want bigger back seat for long runs to BikeWeek, etc.

Thanks for your comments. Bob

 

Welcome to DTR!

I would go with a 5.9 with the 6spd (I just actually did ), if you can still find one, that is. The 5.9 is proven. I think the 6.7 is too early to tell on what we can expect from it yet, that goes the same for the 6spd auto, aisin trans.

Tye

 

Aisin is not available in the Regular trucks...

The 68RFE going into the regular trucks is a dual overdrive unit as is the Aisin that's in the C&C trucks... as is the Allison in GM products...

 

So what are people's opinions of manual vs auto reliability? Is the 4sp auto bad news?

 

If you are looking at a 5.9 cummins I would go with the manual!!!
As far as the 6.7 cummins the manual is 350 hp 610 tq and the auto is 350 hp and 650 tq. Dodge seems to have faith in their auto giving it more tq
The manual is geared a little to low that is my only complaint. But it pulls like a mule on steroids

 

.....Agreed!.....

 

I would go w/ the 06 as you can probly find a good deal on one, or even an 07 with the 5.9. The 5.9 has a proven track record and whenever new models come out like this, whoever the manufacturer, there is often a lot of problems in the first year of production. Although the 6.7 is not a big shift from the 5.9 and it has already been used in other applications that makes me suspect it will be reliable right off the bat. As far as manual v auto if reliability is a concern for you I would go with the manual, the newer 48RE seems to be holding up a lot better but if you want the ultimate in reliabiltiy I think the manual is the route to go.

 

manual will be 325hp not 350.

 

Just from a maintenance cost perspective, go with a '06 or early '07 5.9l and manual.
The new 6.7l will cost a lot more in maintenance and I'm sure will require you to be some type of contortionist to do even the simplest of maintenance.

Plus you will have the option of adding more power to the 5.9 for quite a bit less dollar wise the a 6.7l (if they an ever figure out how to BOM them).

Only problem with the manual is that Dodge should have put the G85 transmission behind it instead of the passenger car type G56 transmission. That is why the Cummins is de-rated for the manuals.

 

I just checked and in the 07 Dodge ram truck brochure it states 6-speed manual 350 hp @ 3,013 rpm and 610 tq @ 1400
6 speed automatic 350 hp @ 3,000 rpm and 650 tq @1500 rpm
This is the first place that I have seen the manual transmission rated at 350 hp!!

 

Well all the better then...cause my next one I want another manual.

 

Well as you can see by my sig I drive a lot!!! to say the least. My truck spends its life hooked to a Big trailer. I put 1k on my truck before it had a trailer and since then it stays hooked up. Most of the time my total weight load and all is right around 23-25000lbs. The only time I had an issue was after I crossed 200K I had to put a clutch in it. The clutch really wasnt bad at all but the fingers on the pressure plate had seen better days and the TO bearing was toast as well as the slave cylinder!! Just a hole lot of workin in its like.

As far as the 6.7 goes I have been looking at them and have done tons of reading on them. I don't listen to what the sales men say I talk to cummins guys! A good friend of mine is the shop foreman at a cummins big truck shop in Phoenix and he says it is basically a stroked 5.9 your not really going to have any problems with the motor the basic platform of the motor is like the current ISB and ISM platform!

Now the emissions system is new thanks to our wonderfull government! So the particulate filter,emissions systed and the ULSD fuel and things like that may have a few bugs and the turbo is a water cooled design. That isnt new to cummins just new to the dodges!

As far as the auto 6spd I would wait on that one to get some real world results, I hate being a guinnie pig.

 

What other maintenance will the 6.7 require? As for the G56 it is a tuff tuff tranny. Just tear into one and you can see the differences! It is far from a passenger car! Now the T-56 is a passenger car kind! Even the shifter linkage on the G56 is big and bad! Ball bearing and a solid machine base!

 

If I was buying the 6.7L, I would get the auto (and I am a die hard manual guy). Performance is unreal, ERS is sweet for downshifting with VGT braking, you get more power (650 vs. 610) and the overdrive in 6th yields better fuel economy vs. the G56.

Plus driving the 6.7L with the G56 is "different" from driving with the 5.9L. The engine does not react the same for a given throttle input due to all of the different actuators (intake air throttle, egr valve, vgt, etc). Also when it does a "desoot" the throttle response will change yet again. Not very much, but it will change.

Too bad DCX didn't come out with the 68rfe back in 2003 when they got screwed by Allison and had to stay with the 47re.