<VV> LM trans question

[Mark Plucenik]

I am hoping someone out there can shed some light on my problem.  My car is
a 66 Corvair, 6 bolt Saginaw 4 speed transmission.  The car had a 3 speed in
it when I got it and I just switched it to the 4 speed. The 3-speed worked
fine but the shifter was sloppy so I rebuilt the shifter tube with Clark's
bronze bushing kit.  That went fine, reamed the bushings for a proper fit.
I inspected the used 4 speed trans before I installed it, removed the side
cover, inspected all the gears, replaced the seals, and thoroughly flushed
it. Everything looked good. It seemed to shift OK before the reinstall. With
everything back together I cannot get 3rd or 4th gear.  Reverse, 1st and 2
are fine but no 3rd  or 4th . I've adjusted the linkage every way
conceivable but can't get the last 2 gears.  I did have the side cover off
and I admit it a pain to get the 2 shift forks back in correctly. It appears
it would be impossible to mix up the 2 forks as they are completely
different and if the #3 / 4 fork slipped out on assembly I would have to
think it would cause a racket and do damage when I ran it but no noise or
alerts.  The shifter is the correct one , # 3872875  65-69 4 speed,  with
the correct dimensions.  Any suggestions or ideas are greatly appreciated.

                                                          Thanks, Mark
Plucenik