Ok, so It turns out I wasn't correct or specific on my trans problems.

Went and played with it, now its fresh in my mind,

here it is:

I have 1st and 2nd gear, that don't slip in the classic sense of slipping.

As I accelerate from a stop, first, feels good, shifts to second, second feels good, depending on throttle position somewhere between 20-35, it goes to shift into third, thats when it happens.

No third gear, at this point I might as well be in nuetral. If I'm going slow enough when it happens more throttle will cause it to shift back into 2nd. If not, like I said car's in neutral (for all purposes), not slipping in 3rd, its like there is nothing there.

What I have done so far:

change fluid and filter, fluid was old but not burnt, some metal flakes, not abnormal amounts for an old car. B2 valve looked good (not broken, not worn, maybe it was replaced).

Play with the bowden cable, first I confirmed that its not broken, then I adjusted it so as to make the problem easier to diagnose, by increasing the tension some, I get later shifts, which helps to know what gear its in.

So next, I tried disconnections the vacuum to the vacuum modulator. Drove like this, makes for hard 1-2 shifts but no change going into 3rd.

Tried adjusting the T handle, in both directions, not the proper method of adjustment, just trying to see if I can make a change in its behavior at this point. No real change.

So what else can I look at?

Any thoughts?

Oh, and the trans isn't making any noises.