U Joint again?

[jmsneorrcom]

What do you mean upside down? Im ASSUMING that you meant you had it to where the grease fitting was facing in towards the yoke and not out to where to you could grease it?

no, I had the drive shaft upside down

 

[3dubs]

no, I had the drive shaft upside down

OK now I am really confused. The drive shaft spins so how can it be upside down?

 

[rnd-motorsports]

I guess I will bite also HOW DO YOU GET A DRIVE SHAFT UP SIDE DOWN do you mean swapped end for end????

 

[Fleg]

I think this is one of those common problems that people think they fix. The slip shaft (don't know it's actual name) that goes inside the T-case or the yoke on the axle can be attatched to the driveshaft via the u-joint either one way or 180 degrees the other way. People "think" they solve a vibration problem if they rotate the driveshaft 180 degrees and re attatch to the u-joint.

The problem is most driveshafts are balanced as a single unit and it doesn't really matter. They are not balanced with the yoke or the slip shaft.

 

[zout]

You can have a drive line out of "time" by the yokes not being aligned once assembled by the slip joint - thereforefore putting a stress on the joints. Or just beating the crap out of a joint till it fits or grind on it when something else is wrong just to make it fit,

Once the joints are in - they should rotate freely - the slip joint should be in "time" with the other yoke - that other yoke joints should rotate feely without any undue stress. The clips to hold the joints in should be tight - but not have to be hammered in or forced or ground down to make them fit. These are someone of a precision component. If anything does not fit right - there is something else wrong and needs to be looked at till it is corrected to make them fit proplerly.

Otherwise - you have a consistant problem. Cheaper to fix it the first go around.

 

[rickf]

Zout, That is called phasing. As that shaft turns the u-joint speeds up and slows down through a 360 degree rotation. The joint on the other end have to be in phase so that the joints on opposite ends are speeding up and slowing down opposite of each other therefor cancelling out any vibration. That is why it is important to have the same u-joint angle at both ends of the shaft. I have seen many, many lifted trucks where the rear is rotated up too line up with the shaft at the same time the other end is a sharp angle. This will vibrate every time and joint life will be very short. The one exception to this rule is if you have a double carden joint at the transmission end. Then the two joints at the one end cancel out and the shaft will go straight at the rear.

Rick

 

[rnd-motorsports]

Amen and glad to hear you testifie zout! Cheaper to fix it corectly the first go around!! 3dubs problem was he just sprang or bent the ears on the slip yolk just needed to spring them back.

 

[zout]

RickF - thanks - I knew there was a physical name besides in "time" but I just could not remember it - been a long time since I had heard it. Over the years its just been easier to explain the other term.

 

[rickf]

I used to own a 4X4 shop in the 70's, I am real familiar with drive shafts. If once you get the joint in the yoke is stiff you can smack the yoke with a hammer just below each cap you had put in. This will usually free up the joint by backing the caps out to the clip.

Rick