2007 5.4 screw

I had my first problem with this truck at 73000 miles today. Under hard acceleration it hesitates and feels like my transmission is slipping. Under easy/normal acceleration it feels just fine but when I'm under moderate to hard it seems to slip right around 40mph before it can up shift. At WOT it revved almost to redline and hardly had any pull, when I backed off it shifted fine.

At first I thought it might be my torque converter or something serious but after some research I see the U joint and slip yoke can cause something similar to this. Am I correct on this? Also does anyone have a link to repair this issue, I believe there's a TSB out on this as well. I'd rather do it myself since I'm out of warranty and don't want to pay the dealership.

I would also like some input on if this sounds like it could be a different issue

Btw no idiot lights are coming on, just doesn't feel right when under hard acceleration.

 

I wouldn't think a u-joint or slip yoke would cause what you are experiencing. Have you checked the tranny fluid? Have you ever had the transmission serviced (filter and fluid)? I would check the level first and observe the colour and smell of the fluid first and go from there as far as the transmission is concerned.