I just finished installing a t-56 into my 83 T/A and am ready to install the drive shaft. Problem is, I removed it back in 1994 and didn't make any reference marks. Yes, I'm an idiot.

I took it to a machine shop today to get new u-joints pressed in. They said I needed to get it balanced because there's no way to make an educated guess, however, I noticed that there is a weight welded to one end...... would this be any clue as to its orientation w/ the yoke? Also, I'm not sure which end of the shaft should be coupled to the yoke.

Should I:

A - Take a SWAG at it?
B - Have it balanced for $110?
C - Buy one from a wrecking yard and just replace the u-joints?

If it was balanced when you took it out, it'll still be balanced when you put it back in.

But I took it apart and there are four different ways it could go back together.

Weighted end at the rear.
Weighted end at the front.
Weighted end at the rear w/ yoke offset by 180 degrees.
Weighted end at the front w/ yoke offset by 180 degrees.

I have a 25% chance of putting it back together the way it was. If I get it wrong, wouldn't that throw it out of balance?

Chances are, not enough to make a noticeable difference.

The driveshaft isn't balanced with the tranny or rear end on so what difference does it make. Why would you buy a used one at a wrecking yard?

But is it balanced with the yoke attached?

If so, I could see it making a difference...... hopefully not a noticeable one, like Apeiron said.

Yes, they're balanced with the yoke attached, but the yoke itself is a fairly well-balanced piece.