vibration troubles!!!!!

[itsaMustangtoo]

new member here old member there you install a t-5 you said you use one early eighties one.are you using a rad four belling if so the input shaft is not going in to pilot bearing.to get this you must use a bushing like the one in tech section or you can use a longer input shaft.the one out of a 94 or 95 t-5 will work fine.i have a 78 king cobra did this conersion works great good luck http://www.mustangii.net/t5swap.asp

That would give a vibration , a missing or incorrectly sized bushing could do it too.

 

[LILCBRA]

Sorry, just went back and read your first post again, you did take the tires off.

 

[2muchtime]

but with the car on jackstands you can go through the gears up to 5th gear , and peg the speedometer to about 120mph let off the gas quickly take it out of gear and kill the motor, the thing vibrates the whole car till the speedo comes back down to about 45-50 . thanks mike d.

i went back to the first post and didnt see that he shut the motor off...
and 89fiveoh you never did say what you had for a bell housing??

 

[LILCBRA]

you said you swapped an 8" from a maverick. did you swap the whole rear, or just the chunk? is there a possibility of one of the axles being bent? maybe a bad bearing in the axle. you did say the vibration was there with the original setup, so i am assuming you had the original driveshaft in it at that time. u-joints are all in order? just some more brainstorming ideas for you.

 

[welder4956]

Something else to think about and try - my 76 V-8 Cobra II came with a weight bolted to the tailhousing of the automatic trans. To me, this meant there was a harmonics issue that the factory was aware of. The weight changes the natural frequency of the engine/trans so that it does not coincide with the natural frequency of the rear axle or some other part. I'm not sure which other part was the concern. You might try fabricating say a 2 lb. weight with a bracket to bolt to the holes on the side of the tailshaft and see if that reduces the vibration.