Well I finally got a good tow in with my new truck. I towed my boat and gear (about 5000lbs) from Virginia to New Hampshire about 700 miles. First let me start off with the bad. I did not really like how the tow/haul button makes the transmission shift all weird. I know it does this to assist with the load but it felt weird and never seemed to want to get up into high gear. It would sort of stick in 4th gear longer then it needed to. I would come up a hill in fourth and then start going down the other side and it wouldn't give me high gear for a while. I figured out if you keep your foot in it longer it seems to switch up faster. I guess it must be some kind of brake assist(for lack of a better term) type of system so when you let off the gas it thinks you are trying to slow down. I tried to turn of the tow/haul mode because of this and my trans temp shot up to 188, so I turned it back on and the temp went back down to 156, which is what it was for most of the trip. Not sure why the button mattered so much? The only thing's I could think of is some kind of fan or cooler that is being turned on with the switch, the other thing I thought of was that maybe the trans is working harder in the higher gears and needs the lower gear so as to not put all that stress on a gear that is to tall(with the tow/haul switch off the trans stayed in the higher gear longer). Not sure about that one but open to ideas or possible solutions. Now for the good, the truck had more then enough power. I was able to cruise at 65-70 the entire time with no problems. If I needed more it was there, however that only came up once. I really enjoyed how the truck seemed to man handle the trailer, no real sway back and forth and the ride was great. I was even able to use cruise on the long flat areas of the trip. I also like how the truck would still get up and go from a stop. I credit that to the 3.92's out back. My MPG avg for the trip was 11.7 according to the computer in the truck. I figured this was pretty good considering the load, traffic and the speed. I was really suprised how the truck rode. For the most part you really could not tell the trailer was back there, the only times you could was when I was on the really bad city roads and it didn't matter what you where in they where bumpy. The truck towed awesome and looked really cool pulling my boat. I couldn't help but stare at it everytime I got out for a break. I could not ask for anything more of my truck I am very pleased and look forward to more trips with this truck.

 

My experience is pretty much the same except a 4,200lb travel trailer vs boat which means more wind resistance. Therefore tranny temp = 200 and mpg = 10.1. (Since 200 deg. is the threshold for tranny oil breakdown, I have the tranny serviced at 18,000 mile intervals - every 3rd oil change and have the dealership do it vs lube franchise due to the 2 tranny filters installation procedure issues)

On heavier loads (7,000lbs), I've found the Tow/Haul to be useful but otherwise never use it. True, it will not allow upshift to 5th and for heavy loads that's appropriate but for lighter loads - not so. (BTW, same experience with my my 4.7 Dakota)

Tow/Haul mode technique: With heavy loads - I start off in tow/haul mode and the shift schedule runs through the following sequence:
1st
2nd
2nd prime (skipped if not in tow/haul mode)
3rd
4th (o/d)

When at cruising speed I disengage tow/haul and it shifts into 5th, consequently providing 6 forward gears.

Now, all that being said, I have Superchips part throttle user defined tuning installed (very conservative downshifts) which prevents un-necessary downshifting for gentle acceleration in 5th gear on overpasses etc.

The disadvantage to that custom tuning is that if I need to downshift to 3rd or 2nd prime in the 55-65mph range for aggressive acceleration, passing etc. I have to either (1.) push the Tow/Haul button or (2.) select the gear I want with the ERS (range select on the shifter handle).

ERS display / actual gear identification:

1 = 1st
2 = 2nd
3 = 2nd prime
4 = 3rd
5 = 4th (o/d)

 

I have found more than enough power to pull with, Hemi/3.92's. I just don't like the rear end squat it has while towing. During hunting season I pull a 2300lb trailer/toy hauler usually loaded with freshcut firewood back from up north. The weight can get around 6500 pounds loaded down. My old 2006 Ram did not squat nearly as much as my new one when towing this amount. I thought I was riding the bumpstops last year with the new coil springs set-up vs. my old truck.

 

Tow haul downshifts earlier, (compression braking) and keeps the RPMs higher (which reduces the load on the tranny) - which is why your tranny temp stays lower in tow/haul. It alos keeps the truck from going into OD.

Works very well, and the other good use for tow haul mode is stop and go traffic. Nice to have some compression braking rather than being on and off the brakes constantly.

 

I'm not sure I'm getting the difference between second and second prime?

The truck has 5 gears...if tow haul mode prevents it from shifting to 5th, that means it has 4 gears. Where did you get "consequently providing 6 forward gears" from? (I mean no sarcasm or anything - total curiosity here).

 

actual gear identification.....gear ratio

1 = 1st.......... 3.00 to 1
2 = 2nd......... 1.67 to 1
3 = 2nd prime. 1.50 to 1 accessible during upshifts in tow/haul and downshifts in all modes
4 = 3rd.......... 1.00 to 1
5 = 4th (o/d 1). .75 to 1
6 = 5th (o/d 2). .66 to 1 accessible only if NOT in tow haul mode


Up shift sequence in tow/haul mode

1
2
3 (2nd prime)
4
5
(6 is not accessible)

Up shift sequence when NOT in tow/haul mode

1
2
(3 is not accessible)
4
5
6

 

More info here:

https://dodgeforum.com/forum/dodge-r...e-5-45rfe.html

Rob

 

I love the "brake assist" thing you are describing, I tow an even heavier load than you mention and this 1500 performs fantastic, it feels like you have a well designed safe system working with you, love it.

 

I'm currently midway through a 650 mile trip from Ft Sill,Ok to Ft Bliss,Tx(El Paso,Tx) I'm averaging 11.5 MPG towing a 6000lb load, tried the tow/haul mode, did'nt like it so I left it in regular mode.When I start climbing some mountains and descending the same mountains, I'll switch it on. The Motel6 I'm in sucks, but I can't complain of the free internet,lol lol.

 

That makes more sense.

That is interesting...if the tranny has 6 gears, why not just make the gear ratios more of an even split across all 6 gears and have it be a 6 speed transmission?

We'd be able to tow like a 3.92 and get the highway mpg of a 3.21...