I realize that this info may not apply to the case, but it may be good for reference. I am not familiar with how the QA's work on the TC series so it may not be the case. Years ago I put an ATI QA on my 2120 (probably over 15 years ago) and have always loved it because it always works and the lever is directly connected to the pins that lock the bucket on. For the last 8-9 years I have used a New Holland factory installed QA on my TN75D. Compared to the ATI, it is an awful design, it works but the locking pins are spring activated where you don't even have good access to the springs. If and when it jams (and it probably will), in my case I have spent hours/days trying to unjam the mechanism.
The engineer in me cringes every time I think of that design. Give me simple, give me ATI or equivalent.
For what it's worth
PS I think I paid over $1000 for my ATI conversion installed 15 or so years ago.
Andy