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07-6-9 6.0L DIESEL ENGINE - BUCK/JERK WHEN PULLING LARGE/HEAVY GOOSE NECK TRAILERS
Publication Date: March 16, 2007
FORD: 2005-2007 F-Super Duty
Some 2005-2007 Super Duty vehicles equipped with a 6.0L diesel engine may exhibit a buck/jerk concern when pulling large/heavy goose neck trailers. For example pulling multiple horses, living quarters, or on board water tank. This concern occurs in tow/haul mode, typically between 35-60 MPH (56-97 Km/h), and requires an input for the buck/jerk to start. For example, the buck/jerk may start after a shift event, torque converter lock up, or hitting a bump in the road surface.
Once the buck/jerk starts, the drivers foot may not be held steady on the pedal assembly and the buck/jerk becomes worse. Releasing the accelerator pedal completely, or going to wide open throttle (WOT) typically will stop the buck/jerk. This concern does not occur when operating the vehicle in cruise control.
Follow the Service Procedure steps to correct the condition.
Since this concern ONLY occurs while pulling a goose neck trailer, it is important that the customer bring the trailer with them in order for the concern to be verified. The buck/jerk condition specific to this concern does not occur when the truck is driven without a trailer, or with a conventional receiver pull trailer.
The buck/jerk concern is caused by trailer configuration and trailer weight distribution causing movement of the vehicle. Combined with a goose neck hitch that is not robust, the hitch flexes causing excessive movement in the truck; therefore the driver is moved in the seat with their foot moving up and down on the accelerator pedal amplifying the concern.
A revised calibration has been developed to help filter out some of the accelerator pedal movement, and show proper trailer loading, hitch location, and hitch information has been provided.
Reprogram the powertrain control module (PCM) to the latest calibration using IDS release IDS-47.10 and higher or IDS-48.4 (expected release March 20th) or higher. This new calibration is not included in the VCM 2007.3 DVD. Calibration files may also be obtained at www.motorcraft.com
. This calibration contains an accelerator pedal filter.
If the concern is still present after the reflash, it may be caused by the trailer weight distribution and/or a hitch not being robust enough for the application.
Refer to the Ford Towing Guide at: www.fleet.ford.com
, then select "Showroom", then "Towing Guides". Towing guide reference material may also be available in the sales department.
Note if the hitch does not appear to be robust or is home made. Some aftermarket hitches are not as robust as others and can cause the hitch to flex thereby causing the trailer to "drive" the vehicle and produce the buck jerk condition. This in turn can cause the customer's foot on the accelerator pedal to amplify this condition. Be especially suspicious of home made hitches, or hitches that do not appear to be robust.
Check the goose neck pin location and if it deviates from the Towing Guide.
Check the trailer set up for distributing the weight as recommended in the Towing Guide. If any deviations are found from the towing guide and/or the hitch is not robust, then the customer needs to be consulted about bringing their equipment up to the recommended guidelines. This may include getting approve to change to a more robust hitch.
Eligible Under Provisions Of New Vehicle Limited Warranty Coverage
IMPORTANT: Warranty coverage limits/policies are not altered by a TSB. Warranty coverage limits are determined by the identified causal part.
OPERATION DESCRIPTION TIME
070609A 2005-2007 F-Super Duty 6.0L: Check DTCs And Reprogram The PCM. (Do Not Use With 12650D, 12650D84) 0.7 Hr.
BASIC PART NO. CONDITION CODE
NOTE: The information in Technical Service Bulletins is intended for use by trained, professional technicians with the knowledge, tools, and equipment to do the job properly and safely. It informs these technicians of conditions that may occur on some vehicles, or provides information that could assist in proper vehicle service. The procedures should not be performed by "do-it-yourselfers". Do not assume that a condition described affects your car or truck. Contact a Ford, Lincoln, or Mercury dealership to determine whether the Bulletin applies to your vehicle. Warranty Policy and Extended Service Plan documentation determine Warranty and/or Extended Service Plan coverage unless stated otherwise in the TSB article. The information in this Technical Service Bulletin (TSB) was current at the time of printing. Ford Motor Company reserves the right to supercede this information with updates. The most recent information is available through Ford Motor Company's on-line technical resources.
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