rkimmell wrote:When the 66 is cold it shifts very normally into all gears. After it gets hot, it gives a very mushy attempt to go into 3rd. It will go in to 3rd but goes into 2nd as soon 
as you give it any gas.Any ideas are appreciated!  Rich
I would ask, if/when this trans has gotten either an overhaul, or perhaps all the
"soft" internal rubber seals have been replaced?  At this age originals I have 
removed are so hard, they will  break if broken.  What happens is the clutch pack 
piston seals start leaking and won't hold the car in gear.  The clutch pack can 
burn up and fill what was a pretty good trans with black poison.  The fluid tends 
to get thinner with heat, so the effect is worse.  
If a trans is otherwise in good shape, all good hard parts, a $30 seal kit can 
restore it for another decade or so.  Unfortunately, if you can't do it yourself, the 
labor is about the same as a complete overhaul.  Any time a 65-67 is overhauled, 
it is very important to assert that the SWITCH PITCH feature is to be retained and 
not discarded as can happen.  Bruce Roe