'05 TH 6x4 Gator- only moves backward

Looking for some direction on the best place to start....I have an '05 TH 6x4 gator, only drives in reverse. It starts and runs solid (great!) but no matter if you have the shift lever in forward or reverse, she only backs up. I found a service manual, but it only shows tear downs- not likely issues. Any advise or words of wisdom is appreciated. I already verified the shift linkage at the tranny is correct (and doesn't need adjusting)

much thanks in advance.
PIN w06x4hd001274

Andy