Does my usage warrant diesel? Cummins 6.7 with AISIN...

[Danattherock]

First of all, having read many, many, old threads here. I want to say up front, the initial cost of the diesel, gas mileage, and ongoing cost of regular oil changes and maintenance are not considerations with my decision. My only concern is which motor will be most reliable in the years to come.

Wife and I have decided on Dodge 3500 Mega cab Laramie SRW 4x4. Hauling 27-28' Airstream (7-8k lbs) through Smoky Mountains of NC and Tenn a weekend or two each month and a big 2-3 week trip each summer out west is main towing usage.

My concern, my daily driving is just 5-7 miles (45-55 mph) into and from town, once weekly driving 30 miles away and back seeing family. And once a month 2.5 hours away to the coast to see family. Sometimes more highway driving, but this is the minimum average.

Then soon adding an Airstream, which we plan to do soon after buying TV. We will take at least one weekend trip a month to the Smoky Mountains of NC and Tenn which is 4-5 hours one way.

Is that enough to keep a diesel happy?

Read they need to be driven a lot to 'clean out'. Read various ramblings about 'Regen', throwing 'Error codes', and such, but not sure how much driving style plays into this. My concern is my driving style may better suit the gas 6.4 Hemi.

An additional variable, I'm very interested in the AISIN $2400 transmission upgrade, but it's only available in the Ram 3500 with Cummins 6.7 diesel. So if going with gas, I don't have this option available to me. Anyone familiar with AISIN? Would love to hear about it.

Our primary goal is to have a long trouble free engine life. Plan is to keep truck a long time. We don't buy new cars often. We take care of them and keep them around. My main question is for our intended usage, do you think the Cummins or Hemi 6.4 would be best?

Thanks for any insights you may share.


Dan
NC

[Danattherock]

Thanks man.

That's a lot to consider.

Motor longevity and reliability is my primary concern.


Dan

[Slowmover]

2500 with gas motor. 5-link coil rear means better ride and stability. As with others, fears about the standard auto aren't warranted.

Takes a lot of miles to warm up a diesel. Engine oil temp will probably reach op temp at the 45-mile mark while solo (unless the factory has some trickery happening). Then one needs that many more miles to boil off acids.

Low annual miles and light trailer mitigate against diesel. An Airstream needs 20% less HP than a box shape trailer to maintain highway cruise.

And the solo mpg reports are encouraging for the gasser. The percentage fuel cost difference is not favorable for the diesel in this application.

And with long term ownership, years out the gasser will need less in maintenance and repairs. The truck will time out before the gas motor needs replacement.

[Bigfoot_affair]

Danattherock wrote:

Bigfoot affair wrote:
Towing in the mountains, get the diesel for sure. The extra pwr and the exhaust brake are worth it alone. I honestly think your selling yourself short just looking at the RAM, all three make great trucks and the other two don't make you pay for a better transmission, they come with it!

Some light reading,

Comparisons

Who is really best in class

Thanks for the links. Interesting.


Dan

No problem, good luck with your decision.

[IdaD]

Hiking Hunter wrote:
Transmission: the 68RFE will do fine for you, save your money. Another note on the transmission - I have the Aisin transmission, and love it dearly, but it has a "4WD LOCK" mode instead of the "4WD AUTO" mode like the 68RFE. The LOCK mode forces all wheels into a hard 4WD and should not be used when the wheels cannot slip some. The AUTO mode can be used when there is only intermittent slippery conditions. In your part of the country, like mine, snow and ice might cover the road, but it would be intermittent. I'm a little apprehensive about using my 4WD "full time" in those conditions if there is ANY dry pavement because of this. Check me on this - I don't think you can get the Aisin with the AUTO mode - I think they are all LOCK mode transmissions. If you can't find a spec sheet showing the available modes on each - look at the 4WD selector knob - it will show either "LOCK" or AUTO" as well as 4WD LOW.

Now, all that being said, the 3500 is a good pick, but consider this: unless you think you might ever get a fifth wheel, why not go with the same engine and transmission in a 2500?. The reasons I suggest this are:
1) the 3500 has a bigger payload rating than the 2500, but if you have a travel trailer that doesn't matter. The tow rating of the 2500 is plenty for your load.
2) The 2500 would ride better for your non-trailer trips because of the stiffer suspension of the 3500.

2500 towing specs
3500 towing specs

Bottom line - 3500 or 2500, 6.7L Diesel, 68RFE tranny

You can't get 4wd Auto in any 2500 or 3500 Ram. All of them with all three transmissions are old fashioned 4wd systems with a locking center transfer case. The only choice in the 4wd systems is whether you want to pull a lever or twist a knob. And based on a lot of years and miles of traveling winter roads, you can run in 4H on intermittent snow and ice on the highway just fine. Just disengage it if you're pulling into a dry paved parking lot or gas station.

I do agree that the coils ride quite a bit nicer, and on a practical level I like that you have separate suspension components that control up and down versus side to side. If a heavy FW is likely in your future a 3500 is the better choice, but if it isn't, the 2500 is a great choice too. Great daily commuter and heavy tow vehicle, with pretty impressive fuel economy to boot.

[Danattherock]

I want the AISIN transmission. It's a better transmission than the stock 68RFE.

It's not offered in any models below 3500

I won't likely buy a Dodge truck with 68RFE transmission. Not after what I have read.

Thanks for the 4wd lock info regarding AISIN. First I've heard of that.


Dan

[Danattherock]

Bigfoot affair wrote:
Towing in the mountains, get the diesel for sure. The extra pwr and the exhaust brake are worth it alone. I honestly think your selling yourself short just looking at the RAM, all three make great trucks and the other two don't make you pay for a better transmission, they come with it!

Some light reading,

Comparisons

Who is really best in class

Thanks for the links. Interesting.


Dan

[Hiking_Hunter]

NCHauler wrote:
Sounds like you want a diesel Dan, for the longevity....Do you need the Aisin? "No". As mentioned the 68RFE is a very good transmission. I'm from the Asheville area and do all my towing in the mountains of NC, TN, SC, VA and WV..last two dually's I owned had the 68RFE tranny and my 5er again, was loaded to 16,300# and I never had the first issue with the 68RFE auto tranny....Nothing wrong with it at all....Now AGAIN, IF you want the Aisin, it is a medium duty tranny, as is the Cummins, a medium duty diesel....With Aisin, you get more HP & TQ and can also opt for the 4:10 or 3:73 tranny or stay with 3:42.....Your money, your call...I purchased my truck because it's going to be my "retirement" truck and I may go with an even heavier 5er than what I have now and plan on seeing the US west of the Mississippi soon, so I figure I already have all the truck I need for doing what I have planned

I agree with all the thoughts of NCHauler here. He's right on target. That's my situation - mine is also my retirement truck and I wanted to cover anything I might want to pull in the future.

Longevity: go with the diesel.
5-7 miles short trips - I agree with the others, probably not quite enough to get your engine hot enough. You wouldn't want to do this all the time, but with occasional longer trips, you should be OK. The problem is you want to get the engine hot enough to burn off the junk in the Diesel Particulate Filter (DPF) system.

Transmission: the 68RFE will do fine for you, save your money. Another note on the transmission - I have the Aisin transmission, and love it dearly, but it has a "4WD LOCK" mode instead of the "4WD AUTO" mode like the 68RFE. The LOCK mode forces all wheels into a hard 4WD and should not be used when the wheels cannot slip some. The AUTO mode can be used when there is only intermittent slippery conditions. In your part of the country, like mine, snow and ice might cover the road, but it would be intermittent. I'm a little apprehensive about using my 4WD "full time" in those conditions if there is ANY dry pavement because of this. Check me on this - I don't think you can get the Aisin with the AUTO mode - I think they are all LOCK mode transmissions. If you can't find a spec sheet showing the available modes on each - look at the 4WD selector knob - it will show either "LOCK" or AUTO" as well as 4WD LOW.

Now, all that being said, the 3500 is a good pick, but consider this: unless you think you might ever get a fifth wheel, why not go with the same engine and transmission in a 2500?. The reasons I suggest this are:
1) the 3500 has a bigger payload rating than the 2500, but if you have a travel trailer that doesn't matter. The tow rating of the 2500 is plenty for your load.
2) The 2500 would ride better for your non-trailer trips because of the stiffer suspension of the 3500.

2500 towing specs
3500 towing specs

Bottom line - 3500 or 2500, 6.7L Diesel, 68RFE tranny

[NC_Hauler]

Bigfoot affair wrote:
Towing in the mountains, get the diesel for sure. The extra pwr and the exhaust brake are worth it alone. I honestly think your selling yourself short just looking at the RAM, all three make great trucks and the other two don't make you pay for a better transmission, they come with it!

Some light reading,

Comparisons

Who is really best in class

If any of that meant anything to me, I'd still own a Chevy, (owned Chevy pick-ups from 1975 through mid year of 2010..last 4 were D/A's...loved them, great trucks and the D/A combo is great...but I went with Dodge dually in 2010 and now truck in my sig....so HP/TQ/how fast to the top of the mountain, how much GVWR/GCWR, etc...is all nice, but wanted to try something different..Have only owned a Dodge Ram truck for a little over 5 years and I like it....I'm in it for the long run hopefully thus the reason I went with the Cummins and Aisin tranny, both components being "medium duty"...guess we'll see...:)

[Danattherock]

Quote...
I think the TFL guys are all on crack. I put no value into their reviews. It isn't about how fast you get up the hill, it is about doing it safely and comfortably. The 6.4 with 4.10 gears would easily tow your rig in the smokey's.

However, it appears you want a diesel. Go buy one, you won't be disappointed, that is for sure.


Actually, I'm still open to the idea of a 6.4 Hemi. For one, I won't have to special order and wait months. And if it will be a long lasting engine, that's my primary concern. Regarding TFL guys, I have my doubts too. But it was still painful watching the Hemi struggle so hard. Chevy 6.0?? Had same trouble in Silverado. Guess mountains are ruled by diesels.


Dan

[Bigfoot_affair]

Towing in the mountains, get the diesel for sure. The extra pwr and the exhaust brake are worth it alone. I honestly think your selling yourself short just looking at the RAM, all three make great trucks and the other two don't make you pay for a better transmission, they come with it!

Some light reading,

Comparisons

Who is really best in class

[Tystevens]

ib516 wrote:
If you're buying based on towing merits, get the Cummins. It's better for towing, hands down. I'm not dissatisfied with my Hemi at all, but the Cummins has more than DOUBLE the torque of the big Hemi (429 vs 900). That makes a difference when towing for sure.

Yeah, but for an 8k airstream? The Cummins literally wouldn't know its back there!

Of course, not a reason not to buy one (as indicated in my prior post, I definitely would!), but certainly doesn't "warrant" buying a diesel.

Note to the OP -- with that trailer, one diesel you might wait for is the Nissan Cummins 5.0. Would likely be a perfect match for 8-10k (provided the truck's ratings are up to par -- they aren't out yet, as far as I know).

Good luck!

[ib516]

If you're buying based on towing merits, get the Cummins. It's better for towing, hands down. I'm not dissatisfied with my Hemi at all, but the Cummins has more than DOUBLE the torque of the big Hemi (429 vs 900). That makes a difference when towing for sure.

[Tystevens]

The only people who "need" a diesel IMO are professional hot shot drivers or those towing huge, huge trailers on a regular basis. For the rest of us, it's a matter of 'want.' You'll not likely be able to financially justify it, and the gas engines out there work just fine for recreational towing w/in their limits.

That said, it is a lot of fun towing with a diesel; I loved mine ('06 Duramax). I vastly prefer how they perform, and loved driving it. If my needs ever put me back in 3/4 or 1 ton range, I'll almost certainly go with a diesel again.

FWIW, many weeks mine didn't do anything but drive the 9 miles to my office and 9 miles back, 5 days a week. It was pre-DEF and regeneration and all of that, but I didn't have any problems at all.

[kmbelt]

Danattherock wrote:
Also, I saw The Fast Lane Truck video of the 6.4 Hemi CC and its run on the Ike Gauntlet was dismal. At one point it was in first gear going 30 mph. Granted, it was hauling 4k lbs more than I would, but still, it was sucking hind tit.

In contrast, their test of the Cummins was the opposite, they bragged about it. Had to let off accelerator so they wouldn't speed. Day and night compared to the 6.4 Hemi. My sole usage will be in Smoky Mtns.



Dan

I think the TFL guys are all on crack. I put no value into their reviews. It isn't about how fast you get up the hill, it is about doing it safely and comfortably. The 6.4 with 4.10 gears would easily tow your rig in the smokey's.

However, it appears you want a diesel. Go buy one, you won't be disappointed, that is for sure.

And i went from a 2008 Duramax/Allison to my current 6.4. Sure, it doesn't have quite the power, but I haven't looked back one single time.

[IdaD]

My daily commute is about 5.5 miles of suburban driving maxing out at about 45-50 mph and my oil and coolant gets up to temp in that driving. The transmission doesn't fully warm up but I doubt that's a big deal. I do get out for longer drives too of course, but not every day by any means. From what I've read these trucks don't have nearly the trouble with emissions on shorter commutes as the older pre-DEF trucks. You may have an issue here or there with emissions, but as far as I'm concerned there aren't any motors out there more reliable than a Cummins over the long haul.

Don't settle for gas if diesel is what you want - the CTD is an awesome expereience and if you settle you'll never be satisfied. Also, have you actually driven them back to back? They're quite different and I knew once I drove the 6.4 that I wouldn't be happy without that straight six under the hood.

As far as Aisin vs 68RFE, I've been happy with my 68 and I think it shifts well. Most of the failures you hear about on them involve tuned trucks. If you keep it stock it's a very reliable transmission.