Drive shaft angle??
Thread Starter
Burning Brakes
Joined: Feb 2009
Posts: 780
Likes: 1
From: Shelby NC
Drive shaft angle??
Threads have said that the angle should be 3 to 5 degrees but should they both be the same plus or minus? If the trans tail shaft is 3 positive should the pinion be 3 positive or could one be positive and one negative or both negative??
Thanks for any direction here--
Thanks for any direction here--
Thread Starter
Burning Brakes
Joined: Feb 2009
Posts: 780
Likes: 1
From: Shelby NC
OK but can one be positive and the other negative? Should both ends be positive or negative? Not mixed or does that matter--
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
As long as the jointed ends of the [main] driveshaft are not of significant length, it shouldn't make any difference. The two joints may need to be 'phased' properly to minimize vibration.
Race Director
Joined: May 2003
Posts: 10,956
Likes: 409
From: California
if your drive shaft and tail shaft both point to ether one side of the car or the other, you will have vibration. ie.. rear end pointing left front, transmission pointing right rear, or visa-versa is good.
Thread Starter
Burning Brakes
Joined: Feb 2009
Posts: 780
Likes: 1
From: Shelby NC
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Team Owner
Joined: Mar 2002
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Race Director
Joined: May 2003
Posts: 10,956
Likes: 409
From: California
if you loosen all the mounts (rear, trans, engine) you can make this adjustment.
http://forums.corvetteforum.com/c3-t...lso-still.html
Team Owner
Joined: Mar 2002
Posts: 24,160
Likes: 78
I fought this vibration problem for years... and this is what it came down to, fixed this angle, vibration went away...
if you loosen all the mounts (rear, trans, engine) you can make this adjustment.
http://forums.corvetteforum.com/c3-t...lso-still.html
if you loosen all the mounts (rear, trans, engine) you can make this adjustment.
http://forums.corvetteforum.com/c3-t...lso-still.html
The diff. sure as hell won't pivot left to right with the way it connects with that huge transverse support. The motor mounts only hook up one way. I suppose the tranny mount could pivot ever so slightly. Did you replace the motor mounts? I suppose if one were busted, it should shift the engine laterally a teensy bit.
Race Director
Joined: May 2003
Posts: 10,956
Likes: 409
From: California
Yeah but there's no lateral adjustment in any of those mountings. Up & down sure but left to right? The diff. sure as hell won't pivot left to right with the way it connects with that huge transverse support. The motor mounts only hook up one way. I suppose the tranny mount could pivot ever so slightly. Did you replace the motor mounts? I suppose if one were busted, it should shift the engine laterally a teensy bit.
The diff. sure as hell won't pivot left to right with the way it connects with that huge transverse support. The motor mounts only hook up one way. I suppose the tranny mount could pivot ever so slightly. Did you replace the motor mounts? I suppose if one were busted, it should shift the engine laterally a teensy bit.
Thread Starter
Burning Brakes
Joined: Feb 2009
Posts: 780
Likes: 1
From: Shelby NC
I understand where you are coming from... it drove me nuts for years....but if you loosen these mounts up, you can get some adjustment, remember, 1/4" up front (engine) amounts to a LOT at the transmission tail shaft. As I said, I fought this for years..... did EVERYTHING first... balanced everything, replaced all that I could.... Vib still there.... did the alignment.... 90-95% of my vibration disappeared. p:-)
Race Director
Joined: May 2003
Posts: 10,956
Likes: 409
From: California
Which is which?? Trans tail shaft points driver side or passenger side? Mine is an undamaged car but the trans is 700R4 with Bowtie Overdrive xmember so it might be off some?? No slot in xmember holes for the mount but the mount has slotted holes to move the trans over either way.
Safety Car
Joined: Oct 2005
Posts: 3,570
Likes: 1
From: Algonac Michigan
As I understand it the trans should be parallel with the frame rails with a 1" offset to the pass. side. The trans should have an approx 3 degree downward angle and the diff should have the same degree angle but up wards. Equal but opposite in the vertical plane.
Instructor
Joined: Aug 2011
Posts: 109
Likes: 6
From: Hessen
Hey guys, this is René from Germany. I currently got my driveshaft balanced to reduce vibrations. That worked quite well. However, looking at the trans and diff angles I think I have a problem... and I do not know how to fix it. I have a pretty original 72 Small Block with Muncie 4 spd. The trans is pointing 2° downward... but the diff is pointing 2° downward too. Now, all mounts (motor, trans and diff are brand new. How ca it be, that the diff is still pointing downward? The car never had an accident. I used high quality mounts... the rubber at the diff is roughly 1" thick. I would assume, the dimensions are correct so do I really have to cut it thinner to get the angles fixed?
Desperately looking for help - thanks!
Cheers...
René
Desperately looking for help - thanks!
Cheers...
René
Safety Car
Joined: May 2004
Posts: 4,366
Likes: 1,589
From: los altos hills california
If you don't have a vibration you don't have a problem. There are two possible configurations for the angle at either end, as long as the angles are equal, either will work.
Instructor
Joined: Aug 2011
Posts: 109
Likes: 6
From: Hessen
Hi Ignatz, thanks for your reply. Wel, actually that is what I am hoping. I had a true "apocalyptic" vibration in 4th gear... the car was smooth as silk until 3500 rpm... but over 3800 rpm brutal vibrations started almost instantly as if the car would fall apart. I never was brave enough to do more than 4200 rpm for just a second or two. Now, with the driveshaft balanced all these vibrations are gone and the car accelerates in 4th gear almost vibration free. Just above 4500 rpm (that is roughly 125 mph) minor high frequency vibrations are present (shift stick is slightly rattling). I do not know if this is still an issue (i am mostly driving on open roads and rarely on the autobahn... and if I do... mostly around 80 mph max) but I would like to understand if there is anything else I can do to further improve. So I thought about the driveline angles... however, they are difficult to measure. But I still have the impression the trans and diff are both pointing 2 degrees downward to the center of the car (instead the diff pointing upward).
What do you think?
Thanks!
René
What do you think?
Thanks!
René