I recently changed my 1981 non turbo 300d trans/torque converter fluid and filter after my reverse gear required full throttle to fully engage. This only started 2 months ago. All other gears work fine. After fluid change it engaged on first startup on flat ground but since then it is doing the same thing. It will lock into gear after about 1 second but will just creep along until I give full throttle for it to fully engage. Once locked in reverse gear it works fine. I am going to work with the reverse band adjustment since it is a 722.1 transmission. Can someone help with what else it could be.

Also for reverse band adjustment, after you loosen the 19mm bolt do you just turn the adjustment screw with a flathead screwdriver? Should I tighten or loosen the screw?

Step by step photo tutorials will be very helpful