Gregg, first of all, thanks for all the assistance you provide to the L community. 
ldtu:
I just put a built motor in my 2003 L using a JLP sb and some Patriot heads with stage II cams. What I am noticing is something I think is tranny related. While in OD with the speed somewhere in a middle range (35-55mph) and easing into the throttle (what I refer to as tip-in), the truck shakes almost violently. If I go into the throttle quickly or if I hit it quickly while that shaking starts, it downshifts into 3rd and all seems fine. At higher speeds, it is not as noticeable but still there. In 3rd (OD off), it isn't as noticeable but may still be there. When the truck was stock and during the entire modding process, this "lugging" type feeling was there but no where near as pronounced as it is now. It was annoying but livable. Others mentioned the same thing and told me they just ran with the OD off unless at highway speeds. My wideband also shows the truck going very rich at that point where the shaking starts.
All I've done to the tranny is your VB plus a larger aluminum pan. I did flush and put synthetic in it way back before I found that wasn't a good thing and I have since changed that out and went back to Mercon. I may need to drain it again to remove any residual synthetic fluid. This was all done pre-new motor.
I also got a "good deal" on an Art Carr convertor that I put in with this new motor. Could that have amplified this shudder? I've since heard it's not that great of convertor.
The fluid looks and smells fine, fwiw.
ldtu: I just put a built motor in my 2003 L using a JLP sb and some Patriot heads with stage II cams. What I am noticing is something I think is tranny related. While in OD with the speed somewhere in a middle range (35-55mph) and easing into the throttle (what I refer to as tip-in), the truck shakes almost violently. If I go into the throttle quickly or if I hit it quickly while that shaking starts, it downshifts into 3rd and all seems fine. At higher speeds, it is not as noticeable but still there. In 3rd (OD off), it isn't as noticeable but may still be there. When the truck was stock and during the entire modding process, this "lugging" type feeling was there but no where near as pronounced as it is now. It was annoying but livable. Others mentioned the same thing and told me they just ran with the OD off unless at highway speeds. My wideband also shows the truck going very rich at that point where the shaking starts.
All I've done to the tranny is your VB plus a larger aluminum pan. I did flush and put synthetic in it way back before I found that wasn't a good thing and I have since changed that out and went back to Mercon. I may need to drain it again to remove any residual synthetic fluid. This was all done pre-new motor.
I also got a "good deal" on an Art Carr convertor that I put in with this new motor. Could that have amplified this shudder? I've since heard it's not that great of convertor.
The fluid looks and smells fine, fwiw.