Just bought a 2012 f350 diesel and started towing my 5er after 900 miles. Between 1st and 2nd gear i experience a shutter. After that its smooth through 6th. Any Ideas

 

That would probably be a drive-line shudder caused by the angle change of your drive shaft with the weight of your trailer. Best bang for your buck is to add air bags to keep the truck height the same without the trailer. Fixed mine.

There are ways to shim the carrier bearing but you will probably end up with a shudder unloaded.

S

 

Spud is correct, it IS a driveline shudder caused by the angularity changes that occur when the truck is loaded. Air bags will eliminate a lot of the problem, as stated above. I have them on my truck. Shimming the center driveshaft support will make the problem worse. That was the fix on earlier superduties but not this one. The center support bracket needs to be made SHORTER. I cut mine down by about 5/8" and eliminated nearly all the shudder, with no negative side effect (in the form of an unloaded high-speed vibration). I tried shimming down and the problem got noticeably worse. I have read that Ford now has a re-engineered replacement driveshaft that cures the problem, but will likely not partake as I have fixed mine to my personal satisfaction.

 

Thanks for the reply's. Your suggestions sound logical but if don't anything will harm the vechichle?

 

If you can live with it I don't think there is any harm. I put the air bags on for two reasons 1. too much sag 2. the vibration.

S