Keith Breslin

iTrader: (10)

I had a 9 inch vibration that i couldnt figure out and search the forum for months. To my surprise i found that the drive shaft was to short and when running a 9 inch you must add at least 3/4 of an inch to 1 inch of length to your factory drive shaft to fix the problem. The 9 inch measure about 11 inches from center of axle to pinion while the 12 bolt and 10 bolt measure 12 inches.

LM97Z

iTrader: (4)

Yes, it will be shorter, i just measured mine from the tranny seal to the front of the pinion yoke, i came up with 45.5" exactly, mine isn't lowered, my stock driveshaft is about 1" too short with the 9".

EPP

iTrader: (22)

I'm glad that took care of your vibration, Keith. Bob

formula98ws6

I have a vibration also. I have a strange driveshaft that is also 1 inch too short. I tried my stock one made no differance. Seems like I have alot of slop in the front yoke I think from not going in all the way. Only problem is this driveshaft cost me like 350 bucks. Hate to spend 300 to 400 bucks if this isn't the problem. Mine seems to get worse in 6th gear running at same speed as 4th or 5th. What was your vibration like. because mine is driving me crazy

formula98ws6

I wish I could just buy a 1 inch longer rearend yoke. But can't find nothing for a 9 inch.

El_Diablo

iTrader: (9)

son of a bish..great thread! Thanks guys.

Keith Breslin

iTrader: (10)

formula98ws6 please trust me. My vibration was horrible especially on the highway. Everyone tells you your pinion angle is off but they are wrong....it might be but unless its way off its not going to cause this bad of a vibration. It got to the point were i hated driving the car so i only put two hundred miles on it in 8 months. I KNEW IT WAS GOING TO MAKE SOMETHING ELSE BREAK. like the back hatch glass. lol the worst thing about this thread is people have had vibrations for a long time with the nine inch and i finally figured out what my promblem and everyone elses promblem was/is with the help of adam.

bigsticksupra

iTrader: (3)

Your problems with the vibration when equipped with a 9" is because your driveshaft is TOO SHORT. Don't wait too long otherwise you'll end up with a spun tailshaft bushing like me. What would swapping back the stock driveshaft do? It is obviously too short... The slip yoke should stick out of the tranny 3/4-1 inch...which is what it will be when you get a driveshaft that is an inch longer. I swapped out a stock length PST for one that is an inch longer and all my vibrations have gone away. I bought mine from Bob @ EPP, great person to deal with, he will get you the correct length driveshaft for whatever rear end you have. It is also warranted for life






wheres my output shaft bushing???