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Discussion Starter · #1 ·
car is a 74 GTV. I'm having trouble with the front section of the propshaft. When the center bearing is mounted on the two studs, the front flange of the propshaft is about 3/4 inch too short -- it does not reach the giubo fully, leaves a gap of 3/4 inch roughly. The trans mount bushing is correctly inserted (mounting hole bottom center) and the mount plate itself is reasonably centered fore-aft in the 4 mounting holes and seems straight left-to-right. Motor mounts are new, Classic Alfa heavy duty ones (square rubber base). The car has been apart for a while: I rebuilt the trans / added flange and speedo sender to accomodate a 4:10 diff. There are two posts in the search that have this issue, but I cant for the life of me figure out how the changes they made added to the length between the center bearing studs and the front of the flange! Center studs have not moved, and are original to the car. No accidents, shunts, etc. The giubos is a garden variety one, same thickness as 3 others I have laying around.

propshaft problem with heavy duty pieces

Front driveshaft issues.

It seems that there is at least one of three things going on
a. The motor/trans is too far forward
b. The trans length from flange face to bell house is too short
c. The driveshaft front section is too short. (Every front section I have is the same length, I know spider/GTV rear section are different length)


So I have a few questions
1. Are all the flanges coming out of the transmission the same in terms of length? One thing I note is that the front edge of the flange is very close to the seal : is it possible that when i rebuilt the trans, I used 'the wrong' drive flange? I do notice that it is impossible to remove the drive bolts on the trans side (the bolts interfere with the case) and I recall way back when there was a way to remove them, but on this one, it is absolutely impossible. If the flange is too far forward (into the trans) that would at least contribute to this.
2. Motor mounts -- anyone else have an issue with these? I dont have a GTV to compare relative motor position : maybe someone reading this with a 74 GTV can take a measurement or two for me?
3. Any other thoughts or ideas? I;m kinda stumped. Thinking that maybe I forgot something in the trans rebuild that would push the flange back but I;ve built a few of these without any issues.. and I do go by the book. The fact that I cant get the bolts out even with the pull out-rotate- jiggle etc makes me extra curious as I'm certain I used to be able to ---
 

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Mine was a little shorter, maybe 1/4" after I replaced the center support.
 

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Discussion Starter · #3 ·
So maybe one approach is to reduce the depth of engagement between the shaft and the center bearing/carrier, ie dont push it so far forward?? Might be able to pick up 1/4 inch there maybe?
Im just perplexed as to what the heck is going on?
 

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Bob, I recently installed my drive line & had same issue. I kept struggling with the shaft, using a pry bar & elbow grease (prob not the best approach) until it went. I was so confused, so I called on help.
 
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Bob, I recently installed my drive line & had same issue. I kept struggling with the shaft, using a pry bar & elbow grease (prob not the best approach) until it went. I was so confused, so I called on help.
I encountered the exact same situation Goats described with my '72 GTV several years ago. The gap was about 3/8" so I made up spacers from brass pipe which are still there today.
While on the lift at Glynn Motorsport the crew puzzled over the problem - everything checked out as being right but the reason for this remains a head scratcher!
 

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Discussion Starter · #7 ·
Paul where did you set the spacers, on the guibo? Today we made up a 6mm spacer and put it behind the bearing to give some more room. I’m going to need another 2mm or do but will do that with washers on the guibo.
 

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Paul where did you set the spacers, on the guibo? Today we made up a 6mm spacer and put it behind the bearing to give some more room. I’m going to need another 2mm or do but will do that with washers on the guibo.
The spacers are placed between the the tranny yoke and the giubo. After sliding under the car this morning I now recall that at some point I'd elongated the holes in the carrier bearing mount and was able to slide things forward about another 1/8" so the spacers are actually now only about 1/4" long. We'd checked to be sure the carrier bearing wasn't installed backwards and that the newer bearing mount matched the previous one, and that the giubo was the same thickness, but everything checked out.
 

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Make sure that the tranny output shaft end is in the female bushing at the end of the driveshaft. Good luck
 

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Discussion Starter · #10 ·
Yes that’s a for sure. The olive on the end of the trans output shaft has to be engaged with the driveshaft busing but not bottoming out — it should be a good .400 inches into the bushing.

I’m going to swap these motor mounts at some point, and go back to “standard duty” center bearing support. This heavy duty stuff is no good for me and my street/freeway driving!!
 

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These are the ones you want to use.

Engine Mount OEM Set of Right & Left 105-115 Cars - Spruell Motorsport, Inc - Alfa Romeo Your Store for Sports Car Performance and Racing Parts

You probably got these. I ended up with some of these on my Giulia Super. The definitely have a little more vibration then the standard ones.


The 73 GTV I talked to you about had the OEM style round put on about a year before I did driveline and head replacement on it.
 
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