[sbchevfreak]

I already posted in the engine forum, but figured I'd put it here too, in case it is a tranny problem.

Here's the rundown: 1990 F150, 5.0L, AOD trans., 4X4. Vibrates really bad, especially after it shifts into third gear, almost vibrates you right out of the truck. Mat the throttle, vibration goes away, once it upshifts to third or O/D, vibration is back. The engine has had a recent tune up, shift points are normal, but just has a pronounced vibration after 2-3 upshift. I don't know a lot about the AOD, could this be tranny trouble?

 

[Max Keith]

vibration

Have you checked out your U-joints, lately?

 

[sbchevfreak]

Yes, u-joints are good, also vibrates slightly in gear, when staionary and you increase RPM.

 

[Max Keith]

vibration

Check the bolts holding your torque converter? Has the engine been out of the vehicle in recent history? Could the flexplate bolts be loose?

 

[sbchevfreak]

Original engine, trans has been rebuilt a couple times, converter bolts are tight. This thing is driving me nutz.:smash:

 

[oldschoolrods]

Have you checked the tranny mount....heard of this happening before causing vibration..

 

[sbchevfreak]

I found it. Just goes to show, don't trust other peoples work. Had someone else do compression test, and they were incorrect. Looks like a flat intake lobe on #8, so it wasn't trans at all. Thanks for all the help, things I will look at in the future!!