This maybe a form of an apology, but I did find the number for the control unit. It was on the upper RH passenger side, rear of unit 9W4016. Gave the tractor a serious pressure wash. All sorts of amazing original details jumped out.
I have a 2 spool 44 unit anyone can have FREE. Its had the cover removed for 25 years, but inside all this time. Its from D4 7U25063sp HT4 loader. You gotta pick up, i can load. The s/n tag is missing.