oops, took driveshaft apart

[ptownTSI]

before i knew you arent supposed to take them apart, i did after i pulled it from the donor car without marking.

what do i do now?

if it needs to be rebalanced should i have the driveline shop install new u joints? i can have new u joints installed for $20 each x2 for whole shaft.

[erik325i]

The front a rear u-joint are supposed be lined up facing the same way, so even if you did not mark the driveshaft, there are only two ways the driveshaft can be facing. Flip a coin to decide which way to possition the driveshaft, and if it vibrates, pull it apart agin and rotate it 180*

-Erik

[AndrewBird]

The front a rear u-joint are supposed be lined up facing the same way, so even if you did not mark the driveshaft, there are only two ways the driveshaft can be facing. Flip a coin to decide which way to possition the driveshaft, and if it vibrates, pull it apart agin and rotate it 180*

-Erik

There are three ways it could be, not two. The transmission side of the shaft has three holes, not two.

[erik325i]

There are three ways it could be, not two. The transmission side of the shaft has three holes, not two.

YOu missed my point.

Both U-joints have to face the same way. When you lay the driveshaft of the ground with one u-joint facing straight up, the other u-joint should also be facing straight up. I would say parrallell, but that is not the right word... It's kind of hard to describe, besides saying that both u-joints need to be facing the same way...

-Erik

[AndrewBird]

You missed my point. The transmission side of the shaft has to u-joint, only a 3-holed flange. This flange can lay flat in three different positions where as the rear has only two ways it can lay. Here:



Rough drawing, but it gets the point. The front joint (Top in pic) can lay three ways. The rear (bottom pic) can lay two ways. So you have actually 6 ways the drive shaft can go together.

[echothreezero]

Erik is on the money - the flange rotation is irrelevant as you just turn the flanges they bolt to to line up the holes one you have the two halves together.

The universals must be facing the opposite way - as they can only face the opposite way in two possible driveshaft configurations, you have two possible ways.

Erik - if they were facing the same way they wouldn't cancel out the phenomena of the output speed of a u-joint varying from the input speed, rather it would exacerbate it.

[echothreezero]

Look here for u-joint theory

[AndrewBird]

Yes, but there is no universal at the transmission. That is what I'm saying. Only one at the diff.

[AndrewBird]

Ok, just had an epiphany. You guys are talking about the universal at the center support bearing lining up with the one at the diff, right? I was talking about the flange at the flex disk and the diff. If so, you guys are correct, those would have to line up. I was wrong.