Last winter I noticed my Jacobsen Imperial 26 snow blower would stop moving forward occasionally. If I put it reverse and backed up a bit and then put it in a forward gear it would go for a time and then do it again. Over the summer I cleaned the rubber band and the disk that drives it. I ran it on blocks through all the speeds and it worked fine. Today I tried to use it in our 6" snow and it again would only go a short distance and suddenly stop going forward. Engine and auger working fine. If I put it in reverse it will back up fine but then when put it in forward again it will go a short distance 5-20' and then the wheels will stop. When this happens the wheels lock up and will not free wheel no matter what position the gear selection is in. Is something out of adjustment that I can tweak?