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Summary of a Towing Trip (long)

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Od Towing Question

Equipment Trailer Questions

I just got back from towing my 27' TT from WI to northern California, and back via Yellowstone. I thought there may be some interest in a few observations I made on this trip.



The truck had 13,000 miles on it when we started ('01 2500, automatic, 3. 54). This was the first big trip with the trailer - only pulled it on two other short trips. I'd never pulled a trailer across the country like this before. I changed the trans. fluid and filter shortly before the trip (at 12,000 miles/1 year old). I also installed a post turbo pyro, trans. temp gauge, and boost gauge. Of course, I also changed the engine oil and filter right before I left. Here's the particulars:



Trailer Weight: Aprox 6,000 lbs

Total Miles: 5,600+ (5,536 documented fuel miles)

Average MPG: 10. 52; Highest: 11. 49 towing, 19. 65 unhooked; Lowest: 8. 49 (bad cross wind)

Total Fuel: 525. 93 gallons

Average Fuel Cost: $1. 61/gallon; Highest: $1. 89; Lowest: $1. 43

Total Fuel Cost: $849. 69

Elapsed Time: 3 weeks.





The truck performed great. I towed out of OD, and the trans. temps stayed around 150 degrees as long as the TC was locked up. I saw trans. temps over 200 at times when pulling a long uphill mountain grade behind slower vehicles in 90+ degree heat or when in city traffic. A few times I saw 250 degrees. :eek: Inspection of the fluid shows it to be ok - good color and smell, so hopefully no harm done. It still works fine. On the hot runs, I had no chance to cool down or pass (2 lane roads). I tried to stick to the interstates as much as possible - the grades are less harsh and passing is more of an option when encountering slower traffic.



It was a great trip. It did confirm to me that the automatic transmission is the weak link. Had I not had a temp gauge, I never would have known the trans. was under stress. It irritates me that they do not hook up a properly engineered automatic to these trucks. I didn't abuse the truck by any means - just towed with it at or below the speed limit. I would most like go with a stick on my next truck because of the towing.



My EGTs were never higher than 800 degrees post turbo. The engine temp stayed at 190-200 degrees and was never a problem. I found out my A-Pillar 3-gauge pod can create a blindspot. I almost ran over a Coyote at Yellowstone when I came around a sharp left turn. My wife saw it way before I did.



The only possible problem is that the engine developed a dull knock or faint tick on the trip. It's barely noticeable - in fact most people wouldn't be able to discern it from the rattle of the engine. Any of us would hear it. There are no other indications of a problem. It runs great - just makes this noise. One suggestion was an injector, so I'll treat the fuel and see if that changes it. Another possibility is it could be just the way it sounds now as it's breaking in (now has 18,600 miles), but that's probably just wishful thinking. It reminds me of a 318 I once had that had a loose wrist pin. It ran great, but had a dull knock.



That's about it. Sorry for the length of this. I hope someone getting ready for a first long towing trip will find this helpful. Anyone with an idea about my engine noise, please throw in your . 02 cents.
 
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I would seriously doubt your "knock" is engine related - betcha its a loose bolt/bracket in your accessory train - alternator, AC pump, or perhaps the serpentine belt tensioner - could even be a motor or transmission mount... Keep us posted if/when you locate it...



Was sorta surprised at your fuel mileage tho' - we made a trip with our fiver when I retired in '96 - from N. California to Florida and back - and averaged more like 16 mpg overall. Our trailer is the same weight as yours, and I was driving the speed limit and above most of the time. I don't spare mine in the hills, I top ANY Sierra grade at 65 mph, and have never had any transmission problems of ANY kind - but now I too have a temp guage installed in the fluid line out of the TC, and under load up steep grades see the same 250 degrees you mention. Never has been a problem - I do service the transmission more often than specified, no burnt fluid, shifts good as new with nearly 110,000 miles on it...
 
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Mileage

Thanks, Gary.



The reason I think the knock is in the engine is it goes with the RPMs and sounds like it's in there. But your ideas sound good. I shall investigate.



Your mileage is great! I would think it's better than mine for a few reasons - 12 valver, higher gear ratio, different - and probably better transmission. I tow in 3rd - about 2300 RPMs at 65-68 mph.



Dave
 
Dave, I was surprised by your fuel mileage also. I made the trip out west (Wyoming and Colorado) with my 24' fifth-wheel (6000 lbs)and averaged right around 15 mpg last August. That was the "99. "



Leaving tomorrow afternoon for Wyoming, Montana, and South Dakota pulling the new trailer (28'). Will see what this ETH can do. I'm expecting around 12 mpg with this setup (taller, longer, and heavier). Also going to scale it before I leave. I suspect my CGVW will be close to 17K.



Looks like you had fun though, but these RAMs have the blind spot in the A-pillar with or without adding the gauge pods. Was in your neck of the woods last weekend.
 
Fireman Dave... at or below the speed limit with 3. 54s could be your problem. Cummins put out a Power Boosters Club newsletter a while back and stated that the best mileage was gotten with a 24 valve at 1800-2000rpm. I'm not sure where this would put you (I have 4. 10s), but you might investigate that. Try a trip in that rpm range and compare. I have found their statement to hold true... don't know about others. Try it and let us know.

Also, I used to live in Montana and go to Yellowstone several times a year. It is beautiful. Got any pics you can post or a story or two?
 
Vince,



Have a great time on your trip. Did you tow with OD on or off?



Rob,



I think that towing at the RPMs I was had the most to do with my mileage. In OD, the Rs are just too low, in my opinion. The higher Rs seemed to be a much sweeter spot for moving along. It's also harder on the transmission to tow in OD. Out of OD is a 1:1 ratio, as I'm sure you know. I was glad to sacrifice mileage for better performance and trans. protection.



That's beautiful country out there. I remember banging on pots and pans to keep the black bears out of our campsite when I was a kid in the '60's. Now it's hard to see one anywhere - which is good. I have a lot of video and undeveloped film. I don't have posting capabilities right now, but maybe I can scan something sometime. By then nobody will care. :rolleyes:



Dave
 
I'm also a little surprized at your milage figures. Although I have a 5spd, I pull my 9K+ trailer in 5th between 1700 and 1900 and almost never fall below 13mpg. Worst I've seen is 12 with a big headwind. My mileage falls if I run in 4th at 2200rpm, regardless of what the sweet spot is supposed to be. The automatic has a higher final ratio, so pulling in OD at slower speeds may be getting you into a lug condition.
 
Originally posted by JohnB

My mileage falls if I run in 4th at 2200rpm, regardless of what the sweet spot is supposed to be.



JohnB... at 2200rpm, you are "out" of your sweet spot for mileage!



MPG sweet spot: 1800-2000rpm.

Power sweet spot: 2000-2200rpm.



These figures come from Cummins, and it looks like you are verifying them. When you go to fourth, try dropping the rpms to 2000.
 
JohnB and Runaway



Are you guys using your on board mileage computer for your MPG's. I assume JohnB is because he is quoting his mileage in different conditions. My 98. 5 doesn't have one, so I do mine the old fashion way. I divide the gallons used into the miles driven per trip and my milelage is similar to Fireman Daves. I have went to the Missoula Montana area with my TT the last three summers and average around 11. 5. There are two pretty good passes between Spokane and Missoula, which probably helps to lower it some.



Chris
 
Originally posted by JohnB

The automatic has a higher final ratio, so pulling in OD at slower speeds may be getting you into a lug condition.



That's exactly the situation. It's lugging in OD at anything under 70mph, and I'm not towing a trailer at that speed.



Dave
 
I have taken three trips out west with my old truck ('98 12V Auto). My total weight was less than Dave's at about 4,500 lbs. I checked mileage at every fill-up and for a total of around 13,000 miles. The average for all three trips was 13. 42 MPG. This was towing in overdrive (unless in the mountains) and doing the speed limit and above (sometimes above more than I should have been:eek: ). Worst mileage was 10. 12 through Wyoming with a 35mph crosswind and going fast. Best was driving in and through Yellowstone with the camper (speed limit 45mph) -18mpg. The biggest problem with the auto was the big jump from drive to overdrive. It would have been nice to have another gear in-between. Also it was a little annoying to hit about 2,400 rpm and have it start to de-fuel and not rev any higher. Oh well, we'll have to see how the new truck does later this year. By the way, nice summary Dave. :)
 
Originally posted by ramfan2

JohnB and Runaway



There are two pretty good passes between Spokane and Missoula, which probably helps to lower it some.



Chris



That would be (1) Fourth of July Pass and (2) Lookout Pass. Both very steep and looong!
 
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Originally posted by johnrv4

[B The biggest problem with the auto was the big jump from drive to overdrive. It would have been nice to have another gear in-between. [/B]



Yes, John, you hit the nail on the head. What gear ratio did your old truck have? I think OD with a 4. 10 would be much closer to a happy medium between performance and mileage. I ordered the 3. 54 because I knew I'd be towing out of OD. I had to replace a transmission in my minivan right before I ordered the truck, so I was gun-shy. Makes you wonder why I didn't go with a 6-speed? I did think about it, but I do like the convenience of the automatic (translation: I'm LAZY). :D



Thanks, John.



Dave
 
Nice post Dave, thanks.



I didn't see your towing speed. This has a dramatic effect on mileage. Also, some trailers are a lot more aerodynamic. My Alpenlite looked smoother and was much lower than my current billboard, but suprisingly my new one tows a little easier.



I also noticed that a cross wind destroyed my mileage. Last trip I saw 8. 8 at 70 in a cross wind to 14. 5 at 60 in calm weather.



I still have the BD pressure lock and auto lock I'll let someone have at a very good price. It will allow forcing your transmission into lockup in 3rd or 4th. E-Mail me If your interested and I'll tell you how to get around the limitations.
 
Another consideration on the mileage is that Dave is towing a TT not a 5er. I also pull a TT (35') and I think that unless you have one of the REALLY tall 5ers you will probably get better mileage than a TT. Here's my thinking on it, as the air flows up your truck with a fiver attach it goes up the windshield along the roof and then it hits the front of the 5er at roughly the height of the truck cab and then goes up and over the 5er. With a TT the air goes up and over your cab and then down towards the tailgate and hits nearly the entire from of the TT. The longer the tongue on the TT the worse it would be too. Just a thought. When I towed my TT to Pigeon Forge, TN I ended up averaging 12. 6 mpg and was very happy getting that.
 
Makes sense, Steve. I have a hard tonneau cover, not a cap, so there's a pretty good void space between the cab and the trailer -a lot of area for turbulence.



Dave
 
Silly

This has to be one of the silliest threads I have ever read.

If I couldn't tow in overdrive with the TC locked up I would go buy a Phurd.

I don't care what Cummins said about RPM's and economy. (They probably figured it out with the engine in the shop on an engine stand. ) The best economy (MPG) is in overdrive with the TC locked up and going as slow as it can maintain its speed.

I can't imagine screaming one across country in third gear. A guy wouldn't be able to talk, and couldn't hear the radio. Yhese things weren't made to run like gassers.

DC has tried to make the automatic fool proof, but apparently they have failed. If you run a loaded truck up to the speed you want to travel at in drive and set the cruise control, it will be smarter than the driver. It will maintain the speed and then when it can't it will slow down about 10 mph and unlock the TC. And your MPG will increase something awfull.

Using the can't tow in overdrive theory would mean a 5 speed can't tow in 5th and a 6 speed can't tow in 6th. C-mon, give me a break. I towed horses in a 20 ft gooseneck from Missouri to Montana all one summer with a 5 speed. Total load probably 8000 pounds. Imagine running that trip all the way in fourth. WOW.

I came out of Rexburg ID over the hill into Island Park yesterday Loaded with my camper and my Auto in overdrive with the TC locked it would run from 60 to 75 then drop back to 60 and go back to 75 no problem. I would be a fool to lock it out of overdrive. FLAME AWAY
 
WyoJim



No flaming here, just curious. What is your total weight with your set up? I see that you have addded a VB upgrade. Why didn't you leave it stock?



The last three years I've towed to Montana and used my OD only on the flats or mild grades. I noticed on the big hills it would slip some before shifting down. So I just got in the habit taking it out of OD at the bottom. I do agree that leaving it in OD on the flats is no problem as long as the rpm's stay up so it isn't lugging.



I have since done an upgrade to my VB and TC + added an EZ. I was very impressed with my first tow with the new set up. Look forward to trying it out on a good long grade next.



Chris
 
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