When accelerating from a dead stop, there is a shudder in the front end which you can feel thru the steering wheel.
I've gotten the tranny mounts changed 4 times, it helps for awhile. Now GM is saying "the s-10 shudder when starting is a normal characteristic for the truck"
Any ideas what it could be?

Sure it's in the front end? Mine did that until I got rid of the double u-joints at each end of the main drive shaft, one of GM's lousy ideas I might add.
I ended up getting a one piece rear shaft made with regular, single u-joints at each end.
Before I replaced the driveshaft I put four new joints in as well as the ball and socket ( can't think of the proper name right now). Two days later while taking off from a light the truck started vibrating. It was so bad I thought I had an engine miss but it was the shaft vibrating.
You said they replaced the tranny mounts, I wonder if when they replaced the mounts they knocked the driveshaft into alignment temporarily which got rid of the vibration for awhile.
Just a shot in the dark here....Mike

When accelerating from a dead stop, there is a shudder in the front end which you can feel thru the steering wheel.
I've gotten the tranny mounts changed 4 times, it helps for awhile. Now GM is saying "the s-10 shudder when starting is a normal characteristic for the truck"
Any ideas what it could be?
Welcome to AF, tell them to show you some documentation that describes that condition and how it is considered " normal"