May be looking to trade up....

[mrtrombley]

I may have put this on the wrong forum, so I will try it here.



I have read on here that most of you seem to really like the '08/'09 trucks, I haven't seen a lot of negatives. I have been thinking of looking for a low mileage 2008 or 2009, probably 1 ton dually although a 2500 would probably suit my purposes now as I don't travel so much anymore. For economical purposes would a stick be much better off than the new autos? Would a 3:42 ratio hold up for pulling only once in a while or should the 3:73 be a minimum? And what do you feel is the loss in mpg with 4wd compared to 2wd. What do you guys with the newer trucks get for mpg going empty and when hauling loads?



I have seen Dave Smith Motors of Kellogg, ID mentioned on here as a good dealer. I follow Greenville Dodge's website from Greenville, TX. They seem to have a good selection and reasonable prices. Any others?



Thanks for any responses.

 

[HBarlow]

I can offer my opinions. They are worth what you paid for them.

The new and vastly improved generation of computer-controlled six speed automatics are very efficient. My guess is they are about as fuel efficient as the manual six speeds and a lot more relaxing and pleasant to drive overall. Either the MOPAR or Aisin six speed will also be cheaper to own and operate over the long haul than the lousy DMF clutch assembly used in the G-56 equipped trucks.

I would not want a 3. 42 ring and pinion under any circumstance. A new Dodge will operate at only about 1200 rpm at interstate highway cruise speed with a 3. 42 gear. Obviously, this engine speed is well below peak torque rpm in a Cummins ISB and under a load, would lug the engine. To avoid that the driver would have to downshift to fourth direct for towing. Why do it? What is the advantage of a 3. 42 gear other than idling at 65 mph?

A truck should be geared so that the engine is operating in the most efficient rpm range at its normal highway speed for best efficiency. IIRC, peak efficiency of our engines occurs at around 2150 rpm.

My truck, with 4. 11 gears and Aisin six speed automatic is running 2150 in sixth gear/second OD at around 70 mph which is ideal for cruising interstate highways. I don't like to tow my heavy fifth wheel at that speed except on an interstate with a tailwind if I'm in a hurry. I prefer to slow down to about 62 mph and run in Tow/Haul mode. This locks out sixth gear and increases engine rpm back to its most efficient range, about 2150 rpm. At 2150 rpm in fifth my truck will pull gentle rolling hills without a downshift and is very relaxed with the trailer behind. So am I.

A truck with 3. 73 gears has less load starting torque and has to run faster on the highway running into increased wind resistance to operate at peak engine efficiency. I don't see any advantage of 3. 73 gears unless that truck will rarely tow a heavy trailer.

IMO, a 3. 42 gear should not even be considered unless a truck will be used only as a passenger vehicle.

Now some will be offended at what I have just written and angrily defend their trucks w/3. 73 gears. They will claim that their truck with 3. 73 gears does a great job, etc, etc. Yes, the mighty Cummins can launch and tow heavy loads, even with 3. 42 gears, but not as efficiently. There is a reason Dodge engineers rate a truck with 4. 10 gears to tow an additional 2000 or 3000 lbs.

As far as comparing 2wd and 4wd fuel efficiency, I have never owned a 4x4 truck so don't really know. My guess is turning the front axles and differential all the time probably costs one to two mpg.

 

[mrtrombley]

Thanks Harvey. I have to agree that even though my present truck with 3:73's does pull my heavy load pretty well, it does it at about 1700-1800 rpms at hwy speed. This does cause me to have to downshift it on some hills. If I keep the speed up, it usually takes the hills pretty well. I have actually been pretty happy with the way it pulls. I figured a 3:73 would get me better empty mpg which is what I am most of the time. I run about 65-70 on the interstates. So, would your 4:11's still do that if running at the higher rpm (sweet spot?). Right now, about the only times I get much above 2000 rpm is when pulling hard hills with a load.

I almost wish I could go back to RV hauling, I just saw a '09 4500 4 door w/22K miles, 19. 5" tires and a real nice flatbed type body on it. It is on the internet. Would make a great work truck.

 

[HBarlow]

I honestly do not believe that the 3. 73 gears or even 3. 42 gears provide enough fuel mileage improvement to notice. When I had my '01 w/3. 55 gears several years back the fuel mileage was outstanding but fellow TDR members w/4. 10 gears were posting similar mileage.

If you run empty 90% of the time and pull a relatively light fifth wheel you may save a few dollars on fuel but with the gearing of the double overdrive 68RE or Aisin I'd have to be convinced by actual carefully measured comparisons of two truck driven several thousand miles under identical conditions at the same time.

My truck will cruise over mild rolling hills with my 14k fiver in tow and GCWR of just under 26k but it will also shift down occasionally if running into a headwind or if the grade gets a bit steeper. On edit: I should add, my truck is a C&C rated at 305 hp and 610 tq. so it has a bit less power than a similar pickup. A 4. 10 equipped pickup w/350hp/650tq may not shift down at all or only on steeper grades.

I had similar thoughts about RV transporting yesterday. Early yesterday an old friend and fellow transporter from when we both worked for SJB returned to hauling working for Horizon Transport a few months ago. He called yesterday to ask some questions about his '08 Ram 3500 and said he has moved over to JET Transport now. He says he pulls all the loads he wants and is making money. For a moment I thought of the adventure but quickly reminded myself of all the negatives you and I both understand.

BTW, I bought a Honda ST-1300 earlier this week. All black. Hadn't been on a motorcycle in 30 years and got on it and rode it home from Austin, TX, almost 400 miles. I lived to tell the story!

 

[mrtrombley]

Congratulations on the bike Harvey, isn't that what retirement is for, to enjoy yourself.

I take from what you have said, that your 4:10 gets nearly as good mileage as the 3:73's. That's what I am interested in finding out. My first Dodge Cummins was a '95 160hp auto w/3:55, very underpowered until I had a torque plate put in it at Quartzite. That made a big difference, mileage was in the 20-22 range. My second was an '01 305hp(?) 6 sp w/3:73 and a jake brake. Sometimes wish I still had that, it was geared very nicely for pulling. My present is the '04. 5 325hp HO auto w/3:73. It has always done a pretty good job pulling especially with the added power of the Bully Dog (about 30hp in tow mode). But I have to wonder if that has been part of my transmission problems with it. Makes me think the 4:10 might be a good idea. I do like to go 65-70 on the Interstates, and out west you can go even faster if you want.

Yeh, I am getting bored sitting here going to the same old job every day. I miss the traveling. I do still need to work though for a while longer. If I thought I could make some decent money I would be very interested in RV hauling again. Yes, then I think of the negatives, sleeping in the truck!! Even though I am not tall I still was longer than the truck was wide, very uncomfortable. If I could just make enough to sleep in a hotel! I've thought that if I did it again I would take the passenger seat out and lay a piece of plywood on that side to sleep on. My truck needs to go back to work, back and forth to the job is not doing it any good.

Any way, enjoy your Honda. Ride safe.

 

[HBarlow]

I can't state with conviction that a 4. 10 gear will get the same fuel economy as a 3. 73 when both are unloaded, I have seen no objective comparison testing, but when you study the road speed vs. rpm vs peak efficiency range of the Cummins engine according to Cummins, Inc. , I would have to see convincing proof to be convinced that the 3. 73 is more efficient. It certainly will not pull as well.

There is no doubt that the automatic transmission has to work harder against a 3. 73 gear than against a 4. 10 or that the 4. 10 will launch loads and climb grades better than a 3. 73.

So my point of view is that the 3. 73 gear is not as desirable for a truck that will pull a heavy fiver, even occasionally. Others are welcome to their opinion.

I deliberately ordered my first Dodge-Cummins, an '01 HO 6 speed with 3. 54 gear because at the time I pulled an 8,500 lb. Airstream then Avion TT. It was ideal for that load. Later, when I bought a 14,000 lb. Travel Supreme fifth wheel the 3. 54 gears did a lousy job. Sure, the Cummins could pull it but it grunted and strained the driveline to get rolling and required frequent downshifts on grades. That taught me a lesson about the advantage of gearing.

 

[mrtrombley]

Harvey, here's my "stupid" question. I pulled out an old 2009 brochure that I had kept and noticed that, as you said, the 6. 7 C&C is rated 305hp/610ftlbs. Can you explain that to me, why is it different from the 2500/3500 which is 350hp/650ftlbs? Same engine aren't they? Do the C&C have different emissions equipment on them? They have similar gear ratio's don't they, such as the 4:10? Is it something to do with the PTO setups, etc?

 

[HBarlow]

I've never read anything from Dodge or anyone truly "in the know" that explains the true reason for the lower power rating so my answer is only my opinion.

The cab and chassis trucks are intended primarily for commercial applications so the thinking was probably that plumbers, electricians and others who use the trucks with a heavy service body installed and a load of tools or the guy who runs a bull dozer or backhoe and hauls a heavy gooseneck trailer around probably are more concerned about economy, long term cost of ownership/operation, and long term service life and durability, than the horsepower competition with Furd and GM.

The cab and chassis trucks do have a simpler emissions equipment package than the pickups and are far less likely to experience soot contaminated turbos, egrs, and dpfs or to set CELs and require dealer service.

My truck and several other C&Cs have been perfectly troublefree since the day they were put in service.

C&Cs have a different frame and suspension, and use the Aisin six speed automatic with PTO capability. I don't know but the PTO capability may be involved in the different engine power rating as well.

C&Cs only offer a 4. 10 gear choice with the Aisin IIRC and, I think, 3. 73 or 4. 10 with the G-56 manual. The Aisin has ratios similar to but different than the MOPAR automatic.

If you compare the trucks on a dealer lot you'll notice that the C&Cs have a stack of thinner rear springs whereas the pickups have four or five thick rear leaves. My experience is that the C&C doesn't compress and sag as much as dually pickups do but the C&Cs do ride a little stiffer than a pickup.

 

[mrtrombley]

Thanks for the info, that does explain some things for me.