questionable towing problems

[AKaye]

I have a 2007 3500 dually, auto trans 5. 9 Engine which I use to haul a 5th wheel trailer. Twice while pulling a steep grade and going over the top, I attempted to accelerate and the turbo would kick in going down hill and not allow me to accelerate. The first grade was pulled in extremely hot weather and I attributed the problem to heat in the trans because after 2-3miles downhill or on level grade the trans came back to normal. The second grade was in much cooler weather and once again the turbo would kick in when attempting to accelerate on downhill or level. The truck and trailer are new to me. Do I have a problem or is the problem my driving?

 

[BHolm]

Your question is pretty confusing. I do not understand what you mean when you say the the turbo "kicks in" and wont allow you to accelerate



The turbo is driven by the exhaust gasses from the engine. It is directly in the exhaust stream and is always spinning. As you add fuel (step on the gas) and build rpm the turbo spins faster and builds turbo boost allowing the engine to burn more fuel yet and make more power. I can not concieve of a situation where the turbo inhibits acceleration.



Is it the trans mission shifting that we are talking about? Is it in too low a gear and wont upshift when you think it should? If you pull a big load up a grade and then start back down is it holding the lower gear and keeping the rpms up? That could definately be the trans temp getting up there and the trans trying to keep rpms up to aid in cooling. It shouldn't hold the lower gear very long though. It should upshift unless it senses a big load still, which can be a little deceiving. You may have the throttle open more than you think and the trans still thinks it needs that lower gear.

 

[B.G. Smith]

I have a 2007 3500 dually, auto trans 5. 9 Engine which I use to haul a 5th wheel trailer. Twice while pulling a steep grade and going over the top, I attempted to accelerate and the turbo would kick in going down hill and not allow me to accelerate. The first grade was pulled in extremely hot weather and I attributed the problem to heat in the trans because after 2-3miles downhill or on level grade the trans came back to normal. The second grade was in much cooler weather and once again the turbo would kick in when attempting to accelerate on downhill or level. The truck and trailer are new to me. Do I have a problem or is the problem my driving?

Sounds like you have an exhaust brake. Also if the cruise is set the truck will down shift on descent of a grade if the set point is exceded by 5 mph. As you can see by my signature, mine is a 06. May not pertain to yours at all. bg

 

[BHolm]

If it is an '07 5. 9, the exhaust brake would be a dealer installed version, not the one standard on the 6. 7s. It would also turn off the second you step back into the throttle making it unlikely this is the problem.

 

[AKaye]

Being from SW Colorado you may be familiar with the hill I had the second problem on. It is the hill from Canon City on 50 to the crest just west of Royal Gorge. Once I had reached the top and started down the other side and had reached the bottom and I attempted to accelerate, the gas pedal had an hesitation. If you pressed harder on the pedal it seemed like the turbo wanted to kick in rather than the trans moving to another gear. This condition continued for a couple of miles and then went back to a normal operation. On hills I try to use the rule where you descend the hill at the same speed or slower than you climbed the hill. I do not have a exhaust brake.

 

[JThiessen]

Shift down/turn tow haul on/turn od off. Sounds like you are bogging it down. By the time you hit the bottom, your RPM's are way low and if you then attempt to accelerate, your just bogging it down.

 

[DonFitzwater]

Fan clutch engaging?

 

[BHolm]

It is still kind of hard to tell but I can give you my best guess I do know the hill, been through there many times.



I suspect you generated some heat in the trans climbing the hill, pulling the trailer. The trip down wasn't long enough to fully cool the trans. The trans had most likely shifted down to third, if you were in T/H mode and touched the brakes, it almost certainly was.



So now you get to the bottom and your foot is off the throttle, yet the rpms are high. When you toe back into the throttle it is going to take a fair amount of travel to get the fuelling to catch up with the higher rpms. You would have to pretty much floor it to get acceleration. That hesitation seems to me like it is pretty normal. Also keep in mind that the throttle isn't connected mechanically to anything, it is all electronic now. That might help account for the weird feel.



I think the trans holding the lower gear is a self preservation feature to get it cooled fully from the long pull with the trailer. If in T/H it will also tend to hold the lower gears longer. You were probably also still on a steeper grade than it seemed. The trans may have been holding third gear as designed to help slow the truck.



My bet is that there is nothing wrong, just an adjustment to how the new truck works. I have found that even the auto equipped trucks benefit from driver involvement, especially when towing in the mountains.



My suggestion is to keep track of whether or not you have it in T/H. Use the T/H OD off features to control what gear you are in, shift manually down to second gear if the speeds are low enough to help ease the burden on the brakes. I found that with active participation the auto trucks work very well for towing. I would HIGHLY reccomend an exhaust brake if you plan to tow in the mountains regularly. Once you have tried one, you will be dumbfounded as to how you got along without it. I had one on my '06 Mega (auto) and loved it. They are better yet with a manual trans but that isn't the truck you have. Give it some serious consideration.

 

[PFreeman]

I have an '07 3500 DRW with 48RE, 3. 73 axle and Dealer installed Jake. The truck had 1700 miles on it last week when I left on a 250 mile trip pulling my 14k 5th wheel. All went well for the first 175 miles or so, then it felt as if my trailer brakes were on. On a one mile interstate grade, I had to pull the transmission into 2nd to make it up the hill at 45mph. This continued for the remainder of the trip. When driving empty, the truck holds 70 or so, but has no power. It also holds in 1st gear to about 30 or 35mph, and then shifts hard. I took the truck to the dealer yesterday and was told that the computer showed a code for a failed "kickdown solenoid" which is now on order. I am concerned that my loss of power may be an unrelated problem, but the dealer says that the transmission problem may be causing the ECM to cut the power back. Time will tell! I really love the truck, but this situation is the pits! My fifth wheel is parked 250 miles away, and I'm having to drive a FORD loaner!

 

[231jasonS]

the dealer says that the transmission problem may be causing the ECM to cut the power back. !

MAY? well shouldnt they KNOW if this problem would cause the ECM to cut the power back?



Seems to me like a "Service"writer is telling you the first thing that comes to mind. I hate when they start throwing out maybes. Either its designed to do this or its not. Seems like a factory trained tech should know this, or could find out if the ECM is able to do this.



I hope they fix your problem correctly and get you back on the road very soon.

 

[PFreeman]

Thanks! One of the disadvantges of living in a small town is, of course that the local dealer has only one diesel tech. He's a good guy, but doesn't have a lot of experience since he doesn't see a lot of problems a big dealership would. I feel like they'll eventually solve the problem. I left the 5er in Huntsville, AL (pretty big town), and their D/C dealer had NO diesel tech! So, go figure!

 

[DerekW]

I'm having to drive a FORD loaner!

How are you able to keep sane while driving a ford. every thing is backwords in the wrong place and just plain stupid on all the ford i have driven. and im just biting my lip theres more to it but I have to go.