Truck vibrates in overdrive?

[leroynumber9]

My truck started vibrating in overdrive today, before that it was having trouble keeping speed in overdrive. Any ideas?

I have an 85 k5, 350 with quad jet, 700r and np208.

Vibrates only in overdrive, i put it in 3rd and drove the rest of the way home.

 

[DEMON44]

I'd suggest that is shuddering you're feeling from the tranny. Slipping. Toast.

 

[leroynumber9]

I'd suggest that is shuddering you're feeling from the tranny. Slipping. Toast.

Yeah i have a feeling it's coming from that area, but i'm hoping it's the torque converter.