MTC

I just got the Smarty Jr. and immediately installed the 40 hp tune. Im very happy with the "improvements" it made to the truck. I just have one issue/question.I just got back from vacation with my 11K lb TT and have some observations/ questions for you guys. The route I traveled is two lane highway and I was rarely able to exceed 55 mph during the route. That no big deal, but it just seemed like the truck was not "comfortable" at that speed with the Jr. installed. It seemed like the truck was lugging (RPM's were around 1600) even in tow/haul mode, which I always use when towing. To keep a constant speed of 55-60 mph made the truck seem to lug. Also, if I pushed on the go pedal, even slightly, it would smoke pretty bad and it would lug for a few until the rpms came up. (I use the word "lug" for lack of better term).

Does the Jr. alter the shift points or lower RPM's? The "seat of the pants" feel just doesnt feel right. A buddy of mine told me that I should not tow in the economy mode (40) but that I should use the towing mode (70) when towing. I was wary of doing this due to the other thread stating that the 70 and 100 modes were the same, and I did not want to risk auto tranny damage.Does my experience match anybody elses? Any responses would be appreciated.

Spooler

My opinion with towing with any box or programmer you risk stock auto tranny damage. Keep the RPM's up and you will be less likely to have issues. Lock out 4th when needed and keep the RPM's up to 1800-2100 RPM. Just my .02.

MTC

I know....I love this truck, but my biggest regret is not getting a 6-speed. Just daily driving, the auto is fine, but when towing it just never seems to be in the right gear. The rpms just seem to be too low, even in tow/haul. I tried to tow with O/D off but at 50-55 mph it tachs so high that any mileage gains from the Jr. go out the window.

But trading in on one is NOT an option, so I have to deal with what I have. I have also been told that constantly switching the tow/ haul and O/D off buttons while driving to compensate for traffic to keep the rpms up will damage the tranny. Is there any truth to this?

I really like the Smarty Jr for daily driving, but I tow alot and would like to utilize the Jr. while towing. But it seems like the truck doesnt like the extra power while driving in the 45-60 mph zone. Sure, I can drive in O/D off, but that defeats the better mileage theory. I know that Im kinda talking in circles here, but Im just looking for some advice from others with the same setup.

Bob Wagner

the sweet spot is right around 1900 rpm's

MTC

EXACTLY...but keeping it thereabout with the auto without killing fuel mileage is another issue.

Hey Bob, while I have your attention, would towing in the 70 hp mode work better for me? I havent tried it yet considering the other post about 70 and 100 being similar.

quadman20

It bites not getting your cake and eat it too. Thats were you got to disside with is more important fuel saving or power when pulling. I notice the same thing with my Quad module over all I've learned that I do get alittle better mpg's when towing over stock but not much. When I'm pulling judge on how everthing feels and sounds.
That 1900 is the sweet spot with or with out power added I think.It will actually gain you better mpgs over lugging it @1600 in the long haul as you get full use of the fuel being used over when you lug it you sending more un burnt fuel out the tail pipe.

metalbasher

You guys need to get a lockout for your od. The tow/haul on my 04.5 locks out OD and the rpm's sit at about 2200 at 60 mph in third gear.

bigwheels94

I put some 285/70/17's on my truck, & I can easily cruse @ 60 in 3rd @ about 2000rpm. & @ 75 I'm @ 2000rpm in O/D. Works great.

MTC

My '07 has a tow/haul button and an o/d off button. I have to say Im kinda new to automatics(only autos Ive had were my former Ferd and this Dodge). All other trucks were sticks. I must be listening to the wrong people...I was told that constantly pushing the tow/haul and o/d buttons while driving to compensate for the different speeds would do damage. I was also told that driving at higher speeds in 3rd gear for a good length of time would also do damage. Any truth to any of this?

Like I said, Im used to choosing the gears I want to be in and the gears the computer wants to be in. It was never an issue though till I hooked up the Jr. Now with the extra power, it lugs and smokes too much...

Fiftygrit

Funny I have the quad XZT tow box, 70hp and my TT weighs about 8500 to 10000 depending on what the old lady has filled it with, mine never smokes, and I use tow haul all the time, I cruise at about 60 to 65 and she will pull hills at any speed I want, on the steep ones she shifts down but does not over rev, shes usually at around 1800rpm which is right for my application, 06, 5.9, auto 373 gears.

MTC

On the highway going between 60-70 mph, I have ZERO complaints. At those speeds the truck behaves perfect. Its at slower speeds, between 40-60, where Im having the issues.

DaveB.inVa

Raising your RPM will help out a lot with the smoke. I don't know if pushing the tow/haul button will hurt anything. My Ram is a manual but my parents have a Silverado that is an automatic with the tow/haul button. I drive it pretty frequently as I was in a crash almost a year ago that broke my left leg pretty bad. My job requires me to drive throughout a large chemical plant so lots of shifting can start to hurt after a while with the manual. Their Silverado didn't get an awful lot of use so they let me drive it to work for now, good deal. Anyway I use the tow haul button on it like you do, to force a downshift when I need it. I believe it raises line pressure and alters the shift schedule. Neither one of those things is inherently bad. I've done it on this truck pretty much every time I've drove it and my Dad does the same thing when he drives it too. Its still going great so I don't see any issues with doing it.

As far as lugging the engine... there is an actual definition for lugging. I'll get this wrong, but it will give you an idea. Basically Cummins defines lugging as full throttle operation below torque peak for longer than a certain period of time. If full throttle operation below torque peak does not raise rpm (and therefore speed) then you should downshift to raise RPM or reduce power.

I don't remember where I read that and its been a while since I did read it. But at any rate it doesn't sound like you are actually lugging the engine. You're not operating at full throttle and with the auto if you did try to operate at full throttle it would downshift and raise RPM above the torque peak RPM.

ShutupAndHoldOn

I pull a 14k-16k fifthwheel an I do need to work the OD button quite a bit. I have found exactly the same as you at around 55 (it will hit OD at about 50) and yes it is a bit luggy so I often kick it out of OD. If you bump your speed to 60 it is pretty nice though. As for the person that told you pushing the Tow/OD button would do damage, it won't (unless you push it every 2 second of course).

You do have to do a fair bit of manual shifting to keep it from lugging. I am not sure about using a Smarty JR but on the Smarty SR higher TM settings make it shift a really low RPM

Spooler

This is exactly why I would recommend 4.10/auto for towing unless it is under 6,000lbs. My RPM at 60 MPH is 1800RPM. Bob is right, on the back road I will push it a little and go about 62-64 MPH. That puts me right a 1900 RPM and the truck loves it. It will pull like that all day long and never sweat a hill. Mountains now that is a different story, I need to be a little higher in the RPM range starting out to keep the EGT's down at the middle or top.

rfeiller

at the same time I had both an 03 dully 235hp. with 4.10 gears, automatic, 2wd quad cab and an 05 dully 325hp, with 3.73, automatic 4x4 quad cab.
on the open flat I-10 the 05 outperformed the 03 with a 10,000lb trailer loaded. but on the grapevine on I-5 in so. CA (about 35 mile grade) the '03 shifted and maintained the corrrect rpm range, where the 05 even tho more hp seemed to jump in an out of gears. they both were kept in haul mode.