GTV6 Tailshaft

[Fylnn]

I just reinstalled the reconditioned tailshaft in my GTV6.  That was certainly fun.

I started off going to the manual and it said "unbolt and remove the centre cross-member".  Climbed underneath to realise mine was an earlier one and the central cross member is fixed.  Tried every which way to get the thing and, and being all newly conditiioned, there was not much flex in anything.  After many hours and much cursing, gave up and dropped the whole rear end down and back.  My tailshaft is the type with the front dougnnut on a seperate splined carrier that clamps on the splines on the front of the tailshat.  With the rear end removed, I slotted it into place and reinstalled rear end onto back of tailshaft. 

There has to be an easier way, hoping someone knows what it is.  Must be more than not holding your mouth right?  Basic problem is that could not get the rear spider or doughnut to get past the rear cross member?  Tried dropping the front of the transaxle and cross-member down but that made it worse.  So what is the assembled wisdom?

Peter

[Fylnn]

Thanks for the encouragement, hopefully don't have to practice that often so as to get good at it.

Question 2 that arises, I have heard people discuss 'aligning' the tailshaft when installing it.  Since the transaxle, centre bearing, and rear of the engine pretty much bolt up, there can't be much adjustment in the whole system.  I did leave everything loose and jiggle it around before bolting up, but is there some 'right way' of aligning the whole drive train?

The only hint I found was in the manual where they discuss refitting spacers to the rear engine mount.  My car has no spacers so does that mean it doesn't need any or someone lost them over the years.  I can see the importance of alignment, not sure how you actually achieve it other than using what Alfa provided.

[MD]

FyInn

Even though it may seem like there is no adjustment in the set up, there is and it doesn't take much to put it out of alignment either. For example, a vibration may gradually introduce itself just by the aging and sagging of the engine mounts even though everything was originally well balanced and aligned !! That's how fussy these things are if you are concerned about vibrations to any degree.

Over the years I have managed to get what I call acceptable vibration levels but never vibration free after a rebuild. Perhaps others have had better luck.

As one source of vibration and coupling failure is the issue of alignment, it pays to get this right as a baseline requirement. To do this, I have made an alignment tool which helps but it is not the complete answer as the principle cannot be applied to all the couplings namely the front one. Unfortunately, this is a tedious job but it does get results.

(Please refer to next post)

[MD]

Continued..

Imagine that the yokes that hold the couplings together are simply two discs with parallel faces if the propshaft is to be perpendicular to the engine flywheel and the clutch input shaft. If they are not, the shaft is out of alignment.
Now imagine inserting a feeler guage between these imaginary discs to see if the spacings between them have a greater gap in one direction compared with another. If so, then the answer must be to move the engine mount position, the engine rear mount position, shaft centre bearing mount position, the crossmember fixing position or the transaxle rear mount position until the gap in the discs is the same around the complete circumference. Of course you do this by starting at one end and follow through one step at a time.

To help measure these clearances,  I have made a simple tool that replicates the thickness of a rubber coupling.I insert this in place of the coupling and as it has machined faces, it allows for reasonably accurate feeler guage measurement for parallel. Refer photo.


I hope this helps a little. Be sure to know that you have done well as this job is one of the trickiest to get right on these cars.

[Fylnn]

Thanks good information.  Since the tailshaft is already mounted might just suck it and see for moment.  But next time soemthng is apart, which is probably not far off, might look at measuring some dimensions to check the parallelness of the faces as you say.  Probably if I think about it some more could also check the splined part to see it is on the same axis as the spline in the coupling to check they are at the same angle.