Im kind of new with. A T but another guy in my town has one and wants me to,come help him with it, he can only start it if the back wheels are jacked up, the transmission seems to be stuck in a forward gear, I'm going up in a couple days but what do I check? I don't know if it is high or low gear stuck or could it be somthing else? What kind of checking should I do?
Sometimes, it's just thick oil causing the problem when the engine is cold. Does he have a good neutral once it's warmed up? If so, I recommend Royce's recommendation of using 5W-30 oil. Another thing that will help is leaving it in HIGH gear when parking it. This prevents the oil from getting between the discs and acting like a torque converter when you go to crank it up next time.
If he does not have a good neutral even after it warms up, then I would start by adjusting the clutch as outlined in the service manual. Something else that can cause this problem is worn lugs in the brake drum. The clutch discs wear little grooves in the brake drum lugs. Then, when you disengage the clutch, the discs sometimes are still stuck in the grooves and don't release immediately. Of course, there is no way to determine this for sure or correct it without pulling it all apart.
With the wheels jacked up and the engine running try pulling on the parking brake to the neutral position. Then work the low and reverse pedals alternately. If it is stuck clutch disks, that will usually free them. If the low or reverse causes the engine to kill, you have a more serious problem with either the clutch adjustment or the gears locked.
Well I went up last night to help this guy and it turned out very strange, he had the car jacked up so I tried to start it with the hand brake in nuteral position turned very slow and hard the guy reached in and put the lever full forward spun over quick but did not start, so we towed it and it started he drove it up the road both low and high worked ok, we backed it in the garage jacked it up with it running and I did what Norman said above alternating between low and reverse everything worked fine, by this time the engine was warm when I put the lever in numeral the wheel stopped turning, I said what is the problem?he said it always does this I tow it to start and after I get it running it will be ok, let it set and get cold back to same problem, he is running 10-30 oil it is the high that is sticking because before we started it I had the transmission cover off and he rocked the rear wheel and I see the low band was free
Adjust the parking brake rods, they are too short and when pulling back into neutral they are dragging the brakes.BTDT.
Try switching to 5W-30 oil and leave the emergency brake lever full forward when the car is parked for storage. Having the lever full forward when the car is parked squeezes out the oil from between the high gear clutch disks.
After you change the oil, check the adjustment of the high gear emergency brake cam and make sure its correct. Many posts here on the forum about how to do that. Also check the adjustment of the high gear clutch fingers to make sure they are not too tight. It may well be the clutch can't release because of improper adjustments.