727 2-3 upshift VERY harsh

I recently had my Tranny & Torque COnvertor rebuilt at PTC in Muscle Shoals, AL. I had the tranny pulled out at a local shop, drove it 3 hours to PTC, and waited while the rebuilt it. I came back home and got it reinstalled, and all seems to drive OK, except...

The 2-3 upshift is extremely harsh. All else is normal.

Details:
727 Small Block
3000 torques convertor
Cheetah Manual Reverse VB, no engine braking in 1st.

When the car shifts 1-2, it is firm and surges forward like it is supposed to.

When it shifts 2-3, upshift is extremely harsh. It produced a loud, clunking sound, and seems to jar the entire car, almost like a brief stab on the brakes.

I talked to PTC, and they suggested I back the kickdown band, located outside the tranny, above the shifter linkage off 1/4 turn. I have now backed off about 5/8's of a turn, and it still does it, though not quite as bad.

I do not have an inch-pound torque wrench, so to reset it woul be by feel only.

Should I keep backing off the band, or am I barking uo the wrong tree?

Other Suggestions?

I will call PTC again tomorrow, but wanted your opinions as well.

THANKS!!