I am feeling a vibration through the accelerator pedal when the transmission shifts from 1-2 and into OD occasionally on acceleration. I have about 5500km on truck. My wife drives it mostly. (I have a 160KM commute daily and do not want to wear a $50,000 vehicle out) I have yet to put my Lance on the back, but hope to in the next month.
Almost feels like a torque convertor shutter?
Any feedback appreciated.

 

Mine does the same thing... most noticably when driving slow @ low RPM's, like through parking lots, etc. When it shifts from 1 to 2, I notice a kind of groaning vibration in the pedal. I have no idea what is causing it. I know this doesn't help, but now at least you know you are not alone...

Anybody know the cause of this?

 

Mine has a valvebody on order for that.

 

I assumed it was part of the programming. I was told or read, I dont remember which, that the reason they could put an auto behind the 600 is that the ECM derates the engine during shifts. This allows the clutch packs to get fully seated before you unleash the torque on them. I assumed that the reason that it is more noticable on 1-2 shifts is that you have the capability of transfering more torque in the lower gears than the higher ones. Then again when you go to OD. I have the same shudder. Am I COMPLETELY out in left field on this one?