transmission flare...where to go from here?

[nr5p]

I have an 82 300sd. I bought it knowing about this issue so I don't know how long it has been going on.

When I first got it a couple months ago it had a bad flare from 2-3 and from 3-4. 1st gear was always firm and 2-3 and 3-4 is firm at fairly hard throttle(2-3 only flares at light throttle, 3-4 will shift normal at hard throttle but soft when cold)

Then I installed superior spring kit, I only used the k1 and k2 springs. transmission shift timing is fine. I also have checked the modulator valve and it does leak. HOWEVER disconnecting it does not change the flare. From what I understand if the modulator valve is disconnected(no vacuum going to it) it should eliminate this as the current problem correct?

So after the superior kit I noticed much improvement. 2-3 only flares when cold for the first few miles, then is normal and very firm at harder throttle. 3-4 flares all the time but does flare less when tranny gets warm, it also does not flare at all if the transmission gets very warm, like after driving the car harder.

Since my flare problem goes away when the car warms up and shifts are firm at harder throttle levels does this mean it is not necessarily worn? I would think if this was the case it would flare and slip under hard throttle worse then at very light throttle. I get NO tranny slippage.

Also transmission fluid and filter has been changed and is at correct level.

So what to do or check next? I know I need a new modulator valve cap but I suspect there is something else that needs replaced first. Or maybe it is a sign of a worn out transmission.