We have a 2007 Mega cab short box with a 5.9L in it. 55-65 mph with the truck unloaded, there is a slight vibration under the truck from what feels like the drive shaft or trans area. With the trailer on the truck its about 10x worse. It is very pronounced and annoying. If you nail the throttle it will go away and not come back until the rpm's come back down. We had it in at 1 dealer 2x now. They tell us its normal, that the cummins has done it since 1992 and its the engine emitting a vibration through the torque converter and out the drivetrain. They say it is more evident on longer drive train trucks, cause I also have a 2007 short box quad cab, and it does not do it. I talked to the shop foreman at another dealer, and he said he was not familiar with this being a common problem. The neighbor who has a 6.7L with a long box and his does not do it either. Any ideas?

 

I'd say take it to another dealer, you are not tied to one particular dealer.

 

sounds like the carrier bearing?

 

Either a u joint or a carrier bearing.

 

So none of you mega cab guys have had an issue with this then?

 

none here!!

 

mine started last week,at 65-70 let off throttle and get vibration till i throttle or jake,haven't fixed it yet

 

My Mega has had an occasional driveline vibration since day one.
It is my opinion that the vibration is caused by the amount of flex in the carrier bearing. I will live with it until Ford or one of the Japanese makers comes out with a diesel as good as the Cummins 5.9.

 

Nary a problem here. 37K on my '06

 

Mine used to have that problem but I haven't noticed it for the past couple of months. I posted the problem on another forum and the overall opinion was the carrier bearing needed to be shimmed. I have a level kit. The vibration only occurred when I was towing my ski boat @ around 65- 70 mph.

 

mine does it like crazy from 45-65 mph. I meet a guy the other day who switched out the two piece driveline to a one piece cause he was going through carrier bearings. He says that he has no vibration at all now.

 

Mine does it also at 50-60

 

https://www.dieseltruckresource.com/...ece+driveshaft