I have a 2006 MegaCab with a 5.7L Hemi & 545RFE auto trans.

Wejust returned fromour vacation,which includedtowingour 27 ft. 5th wheel travel trailer 2k round trip. I couldn't be more disappointed with the performance of the tranny. The truck "hunted" for the proper gear relentlessly the entire trip. I tried using all 3 transmission modes, O/D On position, Tow/Haul position, and O/D Off position, without any desirable results, although the Tow/Haul (as I suspected) gave the "best" performance.We started out in South Florida, on flat, level ground, and traveled north into the mountains of Western North Carolina, so I was able to experience the truck's ability/inability in many different enviroments. My trailer weighs approximately 5k pounds, so I don't think that it was a problem of being overloaded, or trying to exceed the truck's claimed ability.

Can anyone offer me any advice on upgrades or modifications that might make my truck more enjoyable to towour travel trailer with?

TIA

 

what speed were you travling at?

 

Highway speeds. On the open Interstate highways, I would either use the cruise control, or manually maintain my speed between 68-72 MPH.

Once in the mountains, the speeds varied with the local posted limits, and the type of terrain.

 

Was the truck shifting all the time or only in the mountains?

 

Worse on flat ground, than in the mountains.

When I would approach an overpass or similar small grade, the truck would bog way down without downshifting to a point (RPM) that I thought was way too low, and then would drop down a gear (or 2?) and rev to the moon. It would then immediately start the upshift sequence, right back to the point of bogging out, and then the whole scenario would repeat itself. Usually at least twice while climbing a typical overpass on the Interstate.

It was very frustrating, to say the least.

 

What do you have one the truck now?

I did not get a chance to tow through the mountains, but I pulled a 14ft covered trailer loaded with furniture as well as having my bed loaded. Towed from Ft. Lauderdale to Ft. Myers and had no problems. Ran in Tow mode, self control speed, and had no problems. I never run the cruise when pulling anything, as this can confuse the computer sometimes and cause short or long shifts depending on how the trailer is pushing/pulling the truck. I too ran about 70 mph.

Now I did get to drive the mountains with the cruise a couple of weeks ago with my roadtrip to Pa and yes, the cruise really sucked then. I don't care though as I don't use that option much. I am to **** and always want control of my vehicle.

If you don't have anything done to your truck, I would start off with an exhaust and power programmer. Then see how your truck runs and you can get both done for less than $1000.00

 

I should have posted that originally. Thanks for asking. My truck is stock, with the exception of true dual exhaust, with 2 series 40 flowmaster mufflers that exit under the rear bumper. I have considered the Superchips Flashpaq tuner and a cold air type intake, but I have not added those items as of yet.

How much would you say that your 14 ft. trailer & cargo weighed?

 

That is just odd. I tow about 5k lbs over the mountains in Colorado (Berthood, Loveland, Vail, Wolf Creek) and I dont have any problems. I dont run anything other than a magaflow exhaust on it. Have you considered taking it to the dealer? Maybe there is something that needs to be adjusted in your PCM. I am sorry, I dont kow that to share with you.

 

I appreciate your input none-the-less.

As a matter of fact, I did take it to the dealer after returning home from vacation. They kept it 2 days so that they could try to get a fault code out of it, or duplicate the problem. They also said that they checked with DC about any updates that may pertain to my VIN#. In the end, they were unable to do anything. Bear in mind, that they had the truck only, with no trailer. I have an appointment to go back tomorrow morning with my 5th wheel attached, so that it can be test driven under the same conditions that I experienced the problems with. I am pleased with their cooperation thus far, as I know that there is only so much that they can do.

 

Hang in there, I would assume that maybe the tranny can stand to have shift points adjusted and that would help. I think the programers would help. I am looking at Diablo for the new programer coming out at the end of the month and may get it. I wonder if maybe a vacumm line is not set properly hence your consistent shifting under load. Also, I did fail to tell you thatI have a QC not the mega cab and that has to to account for some weight difference. Some dealers are great and it looks like you got one. They should be able to help you. Keep us posted please.