transmission detent rollers

[GModelle@domain.elided]

Gentle Alfisti,
The 1750 transmission that came along in a box when I bought my 72 spider is 
in remarkably excellent condition. The inside is clean, the mainshaft end is 
unworn and the synchro rings have a new, textured appearance that is in sharp 
contrast to the worn-out rings on the later tranny that I have removed. The 
two boxes are split and apart on my bench as a means for comparison. My Alfa 
repair manual indicates that there are two "detent rollers" that I have found 
in the boxes "firewall" on the shifter side. These egg-shaped rollers, as far 
as I can tell, don't actually "roll", but slide back and forth inside a 
drilled chase that is aligned with corrosponding grooves in the 1-2 selector 
rod and the 5-R selector rod. The 3-4 selector, the one in the middle, is 
holed right through. Now here's the rub: when I dissassembled the 1750 
tranny, there were THREE of these rollers in the chase!  The manual only 
specifies TWO. I humbly pose the question before the Digest as to how these 
rollers work....It seems as if the rollers block the movement of the selector 
rods when they are displaced by the movement of another. In this case...three 
rollers in the chase would be way wrong!.

Thanks as usual, Digest...
modelle in Somers Point. 
--
to be removed from alfa, see /bin/digest-subs.cgi
or email "unsubscribe alfa" to majordomo@domain.elided