Drive Line angle

[Kevin71]

I looked at the empire article. And shows the trans down 3 degrees and the rear up 3 degrees to balance out.  I am confused.  I thought I have seen where the rear should be down 5 degrees.  my angles are as follows  3.1 degree down at the trans.  .7 degrees up on the drive shaft.  5.9 degrees down on the rear end.  I have a 5 degree shim on the rear to get the 5 degrees down.  So I still have vibration.  What should I do.

[Kevin71]

Oh this is a E body with a 5 speed tremec TKO 600.  522 stroker.  It vibrates when you get on it but not just cruising along at 60 or so.

[Kevin71]

If I take the 5 degree shim out won't that respond in a equal upward movement of the drive shaft equal to that.  In other words would the driveshaft angle go to 5.7 degrees up which would change the angle at the transmission joint.

[ShelbyDogg]

It has to even out. If the trans is down, the nose of the diff has to be up, then lowered 3 degrees when sitting static.  Pretend that the driveshaft isn't there.

[Kevin71]

Along as the trans is down 3 degrees just match the rear end up 3 degrees and the drive shaft will take care of it's self?

[ShelbyDogg]

They throw the driveshaft angle in there to puzzle people. Jack your car up using your rear end to keep it loaded and set your tailshaft to ZERO. Then set your rear end angle. Pretend your driveshaft is not there. Look at my pic. Your trans can be on the left OR right side.




Have a friend by Chicago that put in a gearvendors. Took it to a shop, where the guy thinks he knows what he is doing. I spoke to him for less than a minute, laying out what needed to be done. He rolled his eyes.
Still vibrates. Guy is blaming the engine saying that a bad harmonic balancer wore out the engine. I told him never take his car back to that guy.

[Cudakiller70]

  yup what he said also this

http://youtu.be/gmV4qwLfOMY

[Kevin71]

Isn't the trans supposed to be down 3 degrees, if so all of the rear ends should be up 3 degrees from the factor.  Is this right.

[Chryco Psycho]

this will eliminate vibration but it is not the best for the diff generally the diff is nose down a little so the angle is straight under power as the ring gear climbs the pinion gear , shimming the rear of the trans up could help

[Racer57]

I have a TKO500 with my 383. My tranny is 3 degrees down and is as high as its going to get. After playing with 1,2,3,4,5 degree shims in the front and back sides of the axle, I ended up with 3 degree up on the diff. Anyone that hasn't been told about possible vibration doesn't notice anything even at 80mph, but I do starting around 70.

 Under hard acceleration its smooth, and I've had it up to 110. BUT, when I let off there is a noticeable vibration that stops when you get back on the throttle even slightly until you get back down to around 70.

I've heard about drive shafts being out of phase. Wtf is that and how do you correct it ?

[Cudakiller70]

I have a TKO500 with my 383. My tranny is 3 degrees down and is as high as its going to get. After playing with 1,2,3,4,5 degree shims in the front and back sides of the axle, I ended up with 3 degree up on the diff. Anyone that hasn't been told about possible vibration doesn't notice anything even at 80mph, but I do starting around 70.

 Under hard acceleration its smooth, and I've had it up to 110. BUT, when I let off there is a noticeable vibration that stops when you get back on the throttle even slightly until you get back down to around 70.

I've heard about drive shafts being out of phase. Wtf is that and how do you correct it ?

Phasing, I don't have experience with this first hand, but am told you can rotate your drive shaft 180 and see if your vibration gets better or worse.

[Cudakiller70]

Found this online

[Chryco Psycho]

the ends of the shaft where the U joint is located need to  be in line

[ShelbyDogg]

Exactly, the u-joints have to be a in line to the exact degree. I had a driveshaft into a shop for a balance. Guy calls and asks if I cut and shortened it myself, because the ends were 3 degrees out of phase. 
I couldn't remember what I did, so I said "I've been having you do my driveshafts for 15 years, your guys must've done it"  He fixed it.
It means one end is rotated a little compared to the other. The only way to be sure is to use s factory stock one or have a good company like Empire make you a new one.

BYW, some driveshaft companies only balance at low speed. I found a company that balances at different speeds and found problems with my "shortened" Mopar driveshafts. Since there is an internal shaft and rubber sleeve inside, it balances one way at one speed, then wants different weights, different locations at a higher speed. I don't have a stock, unmodifed shaft for him to try. I had him make me a totally new one. 

[Kevin71]

I am on my 4th drive shaft.  Empire built the last one.  I took this car to a guy that jacks up the 4x4 trucks who supposedly knowns all about angles.  Not so much.  Mine vibrates when you get on real hard.  If you take it easy no vibration.