I think it's around a 1965 era backhoe. I was using it and it was working fine then all of a sudden it wouldn't go in forward or reverse. I've been trying for 2 days now. I go and start it and it will go into forward and then reverse, but only for a few seconds, maybe a minute and then it just completely stops again. Any ideas? Please help!
A ** 300 was a crawler loader, loader tractors were 30,40, 50, 60... or 203, 304... Is 300 the loader tag that's most visible front and center as you step into the cab? In any case, assuming this is the two pedals on the right side, one forward and one back. It sounds like low fluid, do you have the manual to check the fluid levels? how does the fluid look? any water or air after it's been running and stopped moving? Does that have an inspection cover over the bottom of the bellhousing, or an engine to front axle brace that covers that area? if it's just the plate, remove that and check that the torque converter is firmly attached to the flywheel.
Yeah, 300A would be the loader model. You might have an ** 50A but the model isn't real critical. I think your machine is probably newer than 1965. Have heard of issues with the linkage. Make sure all the linkages from the pedals move freely and there's no dirt or mud packed in anywhere. If it needs oil use ** Perma-Tran XL 821. I wouldn't take a chance with a different oil. I think there might be some info in the archives on here concerning the instant reverse transmission. I can't remember if there's a suction screen or filter for the trans. First thing is to check fluid level though.
How about a picture of the linkages the right pedals are connected to. Or if there's no linkages, are there solenoids and wiring on the transmission? That should narrow down the transmission options.
And just like that...problem solved