"Bucking" when towing...

[RSR FARM]

When pulling my 3 horse GN trailer, loaded or empty, the truck begins very violent bucking ONLY during sustained travel between 48 and 52 mph. I am unsure how to describe the sensation but it is a fast lurching back and forth, as if one were hitting the fuel pedal in very rapid sequence. Another description might be that the issue is transmission related, as though the transmission is bouncing between two gears at a extremely rapid rate. Regardless, when this happens it shakes everything and it greatly alarms any passenger!!

Facts:

• 2008 6.4L PSD, CC, 4WD, auto, long bed.
• Job 1 truck, no engine or transmission modifications.
• Issue began ONLY after latest flash (done 10-20-08).
• Issue only when sustained driving between 48-52 mph. Seems to be present at various points in that range but can't pinpoint a single mph.
• Issue vanishes when I let off of the fuel pedal, but will immediately return when fuel is applied in that mph range.
• Issue is absent (or not noticed) if accelerating through that range (merging onto highway for example.)
• Issue is absent when not pulling trailer. Truck is flawless when not towing.
• Road surface/type does not affect the issue.
• Have only noticed issue on relatively level roads. Have not noticed it going downhill with little fuel applied or uphill under heavier throttle.
• Issue present with, or without, Tow/Haul engaged.
• Exactly the same truck and trailer; no changes to trailer. The ONLY change to either has been the recent flash.
• Issue can be duplicated.
• Issue is VIOLENT!!

Any ideas before I take it to the dealer would be appreciated.

Thanks.

Ron

[1/2tired]

At first I was going to blame the Tow Command Module, but since you can get the same results with Tow/Haul off, it sounds like the transmission is "hunting" while waiting for the torque converter to lock up and deliver power smoothly. Will your service manager take a test ride with you? I don't advocate scaring people needlessly, but it could reinforce your point if you can demonstrate the problem directly to the man responsible for the repairs to your truck...

Best of luck with the repairs, but it should be fairly easy to undo the last "fix" for you.

Mark

[Super08]

I recall seeing a tsb on this with the 05 to 07 trucks somewhere. It said something about improper fifthwheel installs or trailer loading. sounded like they didn't really know the cause of it. I imagine the 08 and 09's will be in the same boat. There was just the odd truck that would do it for some reason....

[RSR FARM]

The next time I am hooked I plan to go by the dealership and take the diesel tech for a ride to illustrate the problem; they are more than willing to wittness the issue in person. They also want to check for codes, etc.

Ron

[dieselmankane]

Let us know what happens

[bill2674]

I had my 08 F350 6.4 in the shop last week for a recall and I asked about the latest software flash. The service manager said that Ford told them to stop using the latest flash as it caused some senors to shut down and they were working on a fix.

When you take your truck in, you might want to ask about that.

Hope it helps!

[RSR FARM]

UPDATE: Just talked with the service manager. A Ford Engineer was at the dealership and they discussed the issue with my truck. The engineer said that the issue is almost certainly related to the most recent flash. I have been advised that a correction is in the works and they will call me when the new program is ready to install. From what I am told this issue happens in some percentage of the reflashed trucks, but not in all. Will let you know if the matter is resolved after the next reflash.

Ron

[Ryekidd]

I know this posting is a bit old but was there ever any resolution on this? I have a 2010 F250 (6.4L) that is ahving the same issue only when towing.

Thanks

[sharri13]

Has there been any update on this?

My 2010, 6.4L diesel turbo 4X4 F350 is having the same problem - however it is not at any particular MPH. It bucks violently when the transmission is trying to shift. It happens at the 60/65 mpg mark, then as the system is warmed up it will happen at all speeds, including reversing at less then 5 mpg. This only occurs while towing (tow/haul on).

After speaking extensively with Ford Corp, our local dealership connected a flight simulator to the truck. They said it showed a problem with the ERG. The ERG was replaced. A few weeks later during a 14 hour drive, it was bucking 3-5 times per hour, every hour.

[scraig]

I have a 08 F-350 dually and a similar problem with bucking while hauling my LQ trailer. It only occurs at 35-40 mph when torque is applied lightly and we hit a bump. Have had the hitch inspected and recently had rear helper spring adjusted and extra leaf added as the truck was unlevel. No issues with this trailer when towing with my 2500 Dodge SRW. No problems with my tag along trailer. Local Service Mgr. has ridden with me and witnessed the action, but no idea of the problem. Dealership where purchased has no idea what causes the problem. I see some responses mention "flash". What does this mean? Thanks for any help or ideas. I think it is in the transmission gear shifting. But dealer says a message or code would appear. Well, no code showed up when the EGR valve and engine blew two weeks after purchasing!!! Help out a greenhorn if you will. Thanks

[Ryekidd]

My truck ended up being classified as a lemon. There is an issue with the driveline when under a load that causes it to Buck.

[beaslyb]

mine does it also, not sure if it's tune related or the same as everyone else but it's aggrevating to say the least.

[sy5adm1n]

Also looking for any updates. My truck was doing it intermittently when cold or first thing in the morning heading out. Did it a few times when towing. Now it is doing it quite a bit more whether loaded or unloaded. Using a steady foot, the truck starts to buck and as long as you keep a steady foot it will shake the truck like the engine is coming loose. If you let off or speed up, it catches up, which sounds like maybe the torque converter. Been in twice and they say they can't reproduce it. Its an 09, hasn't been flashed since new. Thanks.

[FordCustomerService]

Hi guys,

I saw that there were a few questions with towing concerns, and I would like to know if those issues are still present. If you are still seeking help with this, please send me a private message with your VIN, dealer name, and approximate mileage.

Cory

[scraig]

I certainly am having this issue but I was told (by Cory) he could do nothing for me. Its obvious to me by all these posts that this is a relevant problem and has been for some time now. I have felt this is a drivetrain, torque converter, transmission related problem. I saw one post (11-7-08 from RSR) that a Ford Eng. stated this is related to a flash and a reflash was being prepared. No followup has ever been posted. So here we all sit with questions and no answers. I found this problem in my truck 2 weeks after purchase on my first trip, but before I could call the dealership the engine blew up on my way home. Since getting the truck back the dealership hasn't done anything to try and resolve this bucking problem except getting an additional leaf in the rear springs from a suspension "expert". You pay top dollar for Ford Tough and this is what you get. Sorry but I'm really frustrated with this so called Customer Service!!