Upshift 1-2 Problem Solved!

I did finally remove the Valve Body from the transmission. Removal was very simple: remove approx. 15 bolts and the VB will fall into your hands.

Then I opened the plate where the 1-2 upshift valve parts are hiding, inspected #17/18/19 Parts on the bench under clean conditions but could not find anything suspicious at all.

Then I removed the VB from my donor transmission and put it on the bench (next to the other VB) and did the same thing. I did not find anything suspicious in the donor VB either. Everything was clean, nothing damaged or sticky. I put it back together.

Then I decided to install the donor VB (This VB is from the transmission that was damaged, metal chips in the oil pan).
Since the VB swap my transmission is shifting 1-2 correctly at 1500 rpm with low throttle.

I am very, very happy for this but I did not find the cause for the late upshift in the
Bad VB that is still on my bench and I want to renovate it.

Can people give me any advise how to open and clean this VB. I wanted to take the time and inspect the VB and possibly find some clues.
What is the process of rebuilding the VB?

Can you help me?

Martin