Recently I swapped my old AOD to a T5 into my 91 5.0 [8D] Everything went in smoothly. Now that its it, it runs great until about 70mph the car starts to shake/vibrate pretty obviously. A few of my buddy have told me several things. Either its the FLYWHEEL that's unbalanced?!? It might be my DRIVESHAFT that's unbalanced!? or my HARMONIC BALANCER isn't balanced?!...If it was the rear that would make the rear of the car shake even at lower speeds...(am I correct?)

I would really like to hear your opinions on possible diagnosis before I start shredding cash for a part.

So if all you mustang gurus' could help a fellow 'stang fan out, that would be much abliged.

 

any kind of driveline imbalance will cause a shake during RPM variations, not speed. have your wheel's balanced.

go out and start your car, slowly rev it all the way up to just before 5k RPM. if you don't get any obviously hard/similar shaking, its not anything in the driveline.

 

I would rule out harmonic balancer...that would happen sitting still. I would guess if you didn't have this before the swap, it is your drive shaft(it is a different one right?) did you use a new clutch?

 

If it only happens at a certain speed that'd rule out a lot of things. Sounds likea wheel imbalance issue, especially since wheel imbalance starts to show around 65-70 mph. Does it vibrate around a certain RPM in every gear? Or does it only do it when you're around 70 mph?

 

Around 4th gear it feels real shaky, enough to make me let off and while the RPMs drop, the vibrationd stops. So yes, mostly when it does it around 70. I'll go run it tomorrow morning and document it more throughly and i'll make another report...I'll double check my wheels though to see if any weights have fallen off by any chance...and go get it rebalanced anyway. (honestly I never even thought of wheel balancing...I guess I sorta paniced and figured it was something wayy bigger since I just did a swap)

i'm gonna try what MattDel told me and rev slowly to 5k and look for any odd vibrations.

Thanks bro for your help.

 

Nah, I actually used the clutch that I got with the T5 I bought off a buddy of mine. The drive shaft is the same from my stock AOD, only I used the yoke that was on the T5 because the stock AOD did not fit due to spline count...You don't suppose that the different Yoke I used made the difference!?

Yeah, the harmonic balancer didn't sound appropriate with my situation as you pointed out. "that would happen sitting still..." and I didn't mess with that part of the car anyhow.

Thanks for your help bro!

 

You must not have neighbors! 5 liters of combustion + 4 am= Angry neighbors

 

Thanks much for the help!

Yeah, I'll try that tomorrow morning and post results. It'd be awesome if this monster of a beast is only related to a cheap wheel balancing...[:@]

 

HAH, no way bro...it's 3AM here. There's no way in hell I'd do a test at this time of night. Your post did make me want to go see what would happen though... never had a complaint yet. lol

 

thats gotta be the driveshaft, i would make sure the yoke is right, the more mph the more slop you will have in it if its not right.