Hi guys i have a 66 2 1/2 duce. i just had a air shift case installed and replaced the sprag that didn't work. i also installed a original pto winch on it which included installing the pto on the side of the transmission. Everything works great but now the truck dont shift down without grinding really bad!! i cant seem to figure it out, the pto is not engaged i checked thats what people said to check. ive been working on this for 2 months with no luck! any suggestions....