Page 35 of Form UE070003 D7 tractor parts book (powershift) "Governor and Decellerator control"
Sorry I cannot scan it, may have to take a picture if that doesn't help you find it. It appears to be a couple of rods hooked end to end with the joint at a small crank in the neighborhood of the firewall to stabilize the assembly. It appears to connect to a lever on a little countershaft which bolts to the front of the injection pump. I would have to actually go look at it to know for sure. Just not that familiar with the setup.
ccjersey-
If you could take a picture of that page and email it to me I would be very grateful.
My direct drive parts manual shows fuel pump and governor control on p. 35.
All the parts diagrams of acc drive and governor housing don't even show a decelerator.
In my book there is just a little cover plate where the decelerator should be.
I am starting to think the decelerator must have been a rare option on 47a's.
Check the Attachment section of your parts manual.