I have checked the linkage, and everything seems to rotate properly. It happened suddenly with no warning. If the shift lever is not all the way to the full reverse point it is in forward. I ordered a service manual, but it is 2-weeks out. I was hoping someone may be familiar with the problem. When the shift lever is put in the full reverse position the tires immediately stop with a clunk.
Welcome to HEF @George the electrician This is a common problem. You will find that the 4 speed will not be able to be shifted while the engine is running & the FNR lever is in neutral & that there is Forward drive happening when the FNR lever is in neutral. Unfortunately, the shuttle transmission needs to be removed & overhauled, as there is a belville washer/spring in the FWD clutch pack that has broken & the broken pieces are interlocking & causing the FWD pack to remain engaged. When you select REV, the machine will not drive as FWD & REV are engaged at the same time. The service manual has step by step repair instructions - overhaul kits are readily available in many aftermarket part supply stores that deal in Case parts.