Shimmy After Hard Acceleration

[w8tnonu22]

I have a 98' GMC K1500 with a 5.7 liter. I have been having an issue for a while. Under normal driving the truck runs smooth, but after hard acceleration or when towing the truck will shimmy once it shifts out and will go immediately away if you make it down shift. If you let the accelerator up when it's doing it and ease back into the gas it will stop within a few seconds. Any suggestions?

[asilverblazer]

I experienced an unbalanced drive shaft that I seem to remember doing similar things.

[w8tnonu22]

Thanks Bro, Any other things to check anyone?

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i think it may have something to do with your torque converter, or maybe tranny clutches. How may miles you got on it? You ever take off in to high a gear with a stick shift? does it feel something like that? I think if it was u-joints they seem to vibrate pretty well nonstop at highway speed once they start going bad in my experience, and making racket under accelleration too.

What gear is the shimmy/shudder ? top gear/4th? If it's smooths out once you downshift in and out of high gear somethng like i mentioned must be wearing out. Maybe you can get some feedback from a tranny specialist on here or MS3dale. He should know who to contact. Maybe you'll get lucky and it's only got some carbon needing blown out of it and when you get on it it runs rough for a minute afterwards.