another question virbration????

[rddaves54]

I have a vibration at 45 miles an hour and it levels out or goes away around 55 miles an hour. I checked front tires, exhaust, motor mounts, u-joints, carrier center drive shaft bearing for tightness and they all seem good.

I was wondering if this has occurred for anyone else and what I might check next. I have had the truck finished and on the road (not much though) for about 12 months and when I first started driving it this was not going on.

When it goes to vibrate or shudder (I am not sure which) I can put it in neutral and it will stop and smooth out would this maybe be transmission related? I am going to look at transmission mount and see if it is tight.