Slight drive train vibration

Dylan

Dylan

New member
I just completed a SOA and in doing so I adjusted the pinion angle to about 12deg from center. I’m aware that this will give me a slight vibration at higher speeds because the pinion shaft is not parallel to the transfer case output shaft. I did this with the intention of adding a cv joint to my rear driveline in the next few months. I also changed the carrier and bearings but reused the ring and pinion. I followed all the steps to setup the ring and pinion (pinion preload, backlash, and proper mesh), and everything went very smooth as it has for me in the past. My concern now is how can I tell the difference between driveline vibration or improper ring and pinion installation? Is it possible? The slight vibration comes in around 40mph and seems to get slightly worse up to about 70mph. It only does it when I’m accelerating or decelerating; if I coast it seems to go away. If it’s just the driveline ill keep driving it until my new one is made, but if it’s the gears I will get that fixed asap as I do not want to destroy them. And again this vibration is not that bad, you really can’t feel it but you can hear it if you listen real close.

1978 Scout, t19, Dana 20, Dana 44s front and rear

thanks
dylan
 
A faulty ring and pinion setup (and bearings of course) will normally result in only "noise" either when the r&p is loaded or in coast.

I'd have to say your actual vibration is the driveline angle, the u-joint system is maxxed out as to ability of angularity. Also the slip yoke is probably now operating in an "over-extended" position and has very little of the spline interface supported internally.

This is all part of SOA conversion trickledown!
 
Thanks for the information! That is true; the slip yoke is extended out enough to see a little bit of the splines. I seem to second guess myself from time to time when doing things that I have not done that often. Also I was unsure what noises or vibrations to expect with an improper gear setup. I also was assuming that I could run with this driveline for at least a couple months of ez driving. The only damage I could see that could potentially happen would be to wear out the u joints. Am I correct in this assumption?
 
There is definitely a significant safety issue involved with running a driveline that is over extended like this. The slip yoke could actually come apart or bind to the point it can't slip when needed to accommodate axle travel in normal street use.

We delt with a near identical situation this past Sunday on sparky's newly acquired Scout II which is spring under still but does have a reverse shackle setup and lift springs:

http://www.forums.IHPartsAmerica.com/norcal-scouts/4071-need-someone-look-Scout-me.html

Sparky is gonna start a reader's rides thread about this rig soon. The oem front driveshaft is exactly one inch too short and would be dangerous to try and use.

The other issue is the same, a u-joint is gonna fail, just don't know when! And that is not a pleasant experience...I had a close friend killed when a driveshaft dropped in his '64 vette and sawed the vehicle in half from whipping, including him.

Please be careful with this, we don't wanna read aboutcha in the newspaper!
 
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