Help aligning propshaft with transmission flange

[maksym]

Need some words of wisdom. I am in a process of reattaching my manual transmission to the car and at the step, where I have to bolt the driveshaft back to the transmission flange. That's where I've discovered the marks that I've made before disconnecting the shaft are no longer on the transmission flange. These are the marks that I do have:

1. The propshaft has my marks, but no factory marks that I can find.
2. The transmission flange does not have my marks, but does seem to have two yellow dots, presumably a factory mark.

How do I align the two flanges? Is there a way to tell the location of the factory mark on the propshaft based on other signs? Also, how are you supposed to align a brand new prop shaft with an existing transmission?

The shop manual claims you can be at most 30 degrees out of alignment to avoid 'excessive vibration and damage to the bearing'.

[fastboatster]

hmm, I thought that there were marks only on the rear diff flange but not on the transmission output shaft flange. I didn't see any on my dsg, maybe the manual trans is different, idk. What does the manual say about the prop shaft replacement? In any case, I didn't really "align" the propshaft and trans output flanges and had no problems with that. Perhaps what you can do is install it as is for now, if you feel some vibrations, undo the bolts and rotate the propshaft against the flange 60 degrees clockwise or whatever angle is between the bolt holes on the flange and repeat that until it feels okay.

[maksym]

hmm, I thought that there were marks only on the rear diff flange but not on the transmission output shaft flange. I didn't see any on my dsg, maybe the manual trans is different, idk. What does the manual say about the prop shaft replacement? In any case, I didn't really "align" the propshaft and trans output flanges and had no problems with that. Perhaps what you can do is install it as is for now, if you feel some vibrations, undo the bolts and rotate the propshaft against the flange 60 degrees clockwise or whatever angle is between the bolt holes on the flange and repeat that until it feels okay.

Thanks, you made me feel a bit better! I definitely do see a giant white mark on the rear of the propshaft, so you are likely correct. Reading the shop manual, they do talk mostly about marking the final drive end and not so much about the gearbox end. They do not talk about 'renewing' the shaft though, so I'm not sure of the procedure besides doing an in-place vibration fit-in. I guess I will put it in and see how it goes. It's easy enough to re-bolt it if necessary.

[maxa4turbo]

hi maksym, how did it go? I have same problem now, long story sort local shop removed my engine on Audi A4 B8 but this mechanic removed transmission and engine attached and he removed the driveshaft "prop shaft" I was so mad. I only ask him to remove the engine so I can send to machine shop. So I notice he didn't mark the prop shaft before he removed now I have to figure out how to install the way it was, there is one factory yellow mark on transmission side but nothing visible on shaft.

There is a way to correct this with dial indicator, it's explained in rear drive repair manual for Audi A4 2001-2005

[maksym]

hi maksym, how did it go? I have same problem now, long story sort local shop removed my engine on Audi A4 B8 but this mechanic removed transmission and engine attached and he removed the driveshaft "prop shaft" I was so mad. I only ask him to remove the engine so I can send to machine shop. So I notice he didn't mark the prop shaft before he removed now I have to figure out how to install the way it was, there is one factory yellow mark on transmission side but nothing visible on shaft.

That's a bummer! Erasing marks from the propshaft was not my only screw-up unfortunately. I think I spent some time looking for any signs or marks of how it was before and eventually bolted it up the way I thought looked the best. I don't think there was any 'excessive' vibration in that area so it must have been alright. Although I had to take the car to a shop and get them remove the transmission again, so who knows how the transmission is fitted to the prop shaft this time. Most of my current vibration comes from the shot bushings in control arms.

The procedure with the dial gauge looks very easy though - your shop should be able to do it in like 10 minutes if this is something you are concerned with.

I don't know how A4 is packaged, but I'm fairly certain you can not remove the engine from S4 without removing the transmission - they come down from the bottom as a single unit using a relatively simple procedure and then you unbolt the transmission from the engine.

[maxa4turbo]

my mechanic said he mark them, but I'll double check with dail indicator when we install