Stupid mistake while replacing guibo

[AncientTV]

First off, long time lurker here. I've gotten all the info I've needed for my '84 318i off of these forums, and it's a great community. On to my temporary lack of intelligence:

I searched the forum and google to no avail (found one thread related to it, but the responses weren't very clear), so hopefully someone here can fill me in. I've dropped the driveshaft so I could fit the new guibo, but in my haste to get this done today, I forgot to mark the alignment of the transmission output flanges and driveshaft input flanges. :(
The other thread I found had to do with the splined midsection, but I never took the two halves apart, so no problem there.

Is there anyway to tell how the flanges should be aligned, and does it really matter if they go back like they were or not? I figured if the driveshaft itself is put together properly, a 60 degree rotation in relation to the transmission output shaft shouldn't be a big deal. I'm probably wrong, though.

[bmwm42]

They only go one way if I'm not mistaken bolt to tranny first then bolt up the driveshaft

[AncientTV]

:???:

I'm talking about where the driveshaft bolts up to the tranny (not my picture):



The parts rotate independently when not bolted together, and I failed to mark the original orientation, so I don't know how they're supposed to bolt back up. I'm wondering if it matters and/or if there's a way to tell which orientation is correct.

edit: I'm only asking because the Bentley manual tells you to mark them. Again, it's not apparent to me why it matters.

[Jaxx_]

I wasn't aware you needed to mark that. the part it says to mark is the driveshaft pieces.

I don't believe the mounting position has an effect on balancing. I did not mark mine when I removed the transmission.

[AncientTV]

My thoughts exactly. I'd like to get as much input as possible though. Paranoid? Yes, but I'm in no rush haha.

[Mike The Bavarian]

you're fine. it's the u joints when doing the csb that you need to mark.

[AncientTV]

Good enough for me, thanks you guys.

[blunttech]

not true.. There are arrows on the guibo pointing to where the flanges should mount. You CAN INDEED install the guibo incorrectly

[stumble_t]

Yup
> to flange
As in, arrow points to corresponding flange

[bmwstephen]

what would happen if you dont mark them? vibrations?

[scottinAZ]

if the guibo isnt installed properly, it will tear itself apart as the interior reinforcement is directional in nature. Most are marked with arrows that must point towards the flange (on trans or driveshaft) other than that, it matters not how they bolt up.