68 RT driveshaft problem

[jww426]

Hello all!

On my 68, the driveshaft keeps going out of round and causing vibration.
I have a 3:70 rear.
Is it the burnout launches that I do far too often?
Should I get a Mancini heavy duty racing driveshaft?
Steel or alloy?

thanks!!
John

[firefighter3931]

If the runout is constantly changing after some abuse....the driveshaft is weak (twisting) and it's probably rusty on the inside of the tube. I'd replace it with a quality piece and some fresh U-joints. 
 
With an auto trans the last thing you need is a broken driveshaft under full load. Once that happens the trans will suffer damage to the sprag. If the sprag is not repaired you can easily explode the front drum and put a nice hole in your floorpan and waste the transmission. 

A broken driveshaft can snowball into a huge mess 


Ron

[jww426]

Thanks!!
JWW