Hi
The Tranny on my new 72 satellite slips some 2nd to 3rd when it shifts and seems to shift all the way into 3rd before 15mph.When in 3rd hold nice and no slipping in any gear at high rpm. Its an automatic 904 I think going to get under there later check it out. I tried to find some reading on the trans and found that the kickdown linkage is also a away to increase the line pressure but I never got the linkage with he car. Found lokar sells Kickdown cables but thought I would ask if this could be my problem before spending the money thanks
Luke

 

You MUST have the kickdown linkage installed or you will destroy the trans. And YES that is the problem.

 

Yep if you drove it and it started slipping the damage may already be done. Unless you have a manual valve body you must have that linkage on and adjusted properly or you will burn up your bands. You want more like 35 to shift into third.
If the slip you feel is a little lag between 2nd and 3rd you are fine.
Line pressure will make it firm but you wanna be careful playing with it.

 

yep the kickdown is the problem. mine did the same. it seemed like it slipped from shifting into 2nd and 3rd. i freaked out, pulled over, and noticed the kickdown lever was laying on my intake manifold... and so was the 35 year old cotter pin. i guess u cant keep every nut and bolt original. i towed it home and replaced the pin. because i didnt drive it i didnt tear anything up

long story short, i have a small hunch this is your problem. i know a guy down here real well who has a bunch of linkage parts for b bodys if u need him hollar at me