b0b

iTrader: (1)

Ok, I have been fighting with pinion angle ever since my S60/suspension. After reading literally probably a hundred threads about this issue I have an idea of what my underlying problem may be. My tailshaft is at a downward angle, towards the rear. In order to create the "equal and opposite" or "parallel" angles, the rear pinion needs to be angled upward towards the front of the car. Creating a " ^ " if you will rather than a " v ". My main question is this angle, the " ^ ", not able to be without vibration. I currently have my angle difference at about 1-2 degrees. The tailshaft/yolk is downhill about 3 degrees and the rear pinion is pointing uphill between 1 to 2 degrees. A difference of 1-2 theoretically creating a 0-1 parallel/difference under WOT/load. After numerous minor adjustments getting it in this close, I still have high speed vibrations after 70ish mph that are pretty bad and also vibrations while in neutral (worst) from about 40mph and up. So is the fact that my rear angle, the " ^ " shape the culprit even though the angle is within accaptable limits. My next move is to shim the rear tranny mount to create an uphill angle towards the rear off of the tailshaft and thus creat a slight " v " in the rear. Will this help?

M6
UMI full length adj TA with relo crossmember
UMI adj LCA
UMI adj PHB
Strano Springs
Koni single adj rears (full soft)
S60

Thanks

speedtigger

iTrader: (16)

Same driveshaft or was it a new one?

b0b

iTrader: (1)

new one from strange, bought with my S60 from Carl.

speedtigger

iTrader: (16)

My new driveshaft from PST vibrated terribly above 55 MPH with a 3.90 gear. They re-balanced it and replaced the u-joints for free and it was much better.

b0b

iTrader: (1)

Hmm.. Do you know any info on my angle question?


Bump

speedtigger

iTrader: (16)

You have it right. For factory 4 link cars like mine, \ \ is the correct arrangement. My car has 3 degrees tailshaft down and 2 degrees pinion snout up allowing 1 degree for pinion climb while accelerating.

Leaf spring cars typically set up 2 or so degrees pinion snout down for this arrangement \ /.

I have seen people set up four links with the \ / arrangment, but that is not how they come from the factory.

I do not know how vehicles with the torque arm are set up from the factory, but I would emulate the factory set up to avoid cruise vibrations.

97FormulaWS-6

iTrader: (1)

Your angles are set properly.

Are you burying the slip yoke too far into our out of the transmission?

The Balance of the shaft might be off as mentioned.

Kevin97ss

Try assembling the joint 180 degrees from where it is now in the pinion yoke and see if it changes.

b0b

iTrader: (1)

^^ I never considered that! That sounds like it has some promise to it.. I will def try that tomorrow..

I messed with it more tonight.. The motor/trans/yolk is sitting at 3 deg downhill, and the rear pinion is abt 1.5-2 deg uphill. That SHOULD be within tolerance of a good working quiet angle setup according to everything Ive gathered here.

b0b

iTrader: (1)

Bump for more comments n suggestions

Kevin97ss

I did not see it mentioned, though it should be asked. The angle readings were taken with the rear suspension loaded and not hanging on a lift or jackstands....right?

b0b

iTrader: (1)

Kevin97ss,
Yes readings were taken with car loaded sitting up on blocks under all 4 corners in a level garage. I'm happy to say that I took ur advice and took the u joint and reversed it in the Pinion and it pretty much solved the problem. It still has a slight vibration in neutral but not near as often through diff speeds or as intense. I'm happy with it now and can get the rest of it out by tweaking a little more I feel. Thanks a lot, look forward to goin to the track this wkend!

speedtigger

iTrader: (16)

That is great news Bob!