Engine shudders when I put a load on it in Drive. If I go to a lower gear it takes right off. 1989 F150 4wd

bad tranny,tranny mount moto rmount.but it sounds like drive is going out.

Does it happen when accelerating from a dead stop, or only when it reaches the final drive ratio (high gear)?

It only happens when I slow down and then step on the gas. Also when I am going up a hill and have to slow and then accelerate. Thanks

I showed your post to a lifelong buddy who took over his father's tranny shop decades ago. Although he cannot be sure he believes it is probably a mount problem. Although it is possible it is a gear problem, he doubts it, adding he has almost never seen gears torn up in a tranny from normal use. He suggested locking out the gears one at a time at a dead stop then accelerate to see if you can replicate the problem. He asked if you are sure the engine is not missing severely under the load.

After he reread both your posts he stated it soulds like the tranny is not automatically shifting from the final high gear ratio back to first. If asked if you're familiar with manual stick shift driving. If the vehicle acts like you're trying to start from a dead stop in third gear on a manual, there is a tranny problem. First check the fluid level in the tranny and it's condition.

The tranny shifts fine. It is the engine. Thanks for your help.