I have a 74 fj40 with a 4 speed transmission. I just had the clutch replaced and the transmission and transfer case resealed. I had this done at a local shop. I was able to drive about 30 miles toward home the day I picked it up before I was locked out of transmission. I was stuck in neutral. I called a tow truck, got home, replaced the slave cylinder, drove it for maybe 20 miles, stuck in neutral again. It was running and shifting fine until all of the sudden it doesn't. I have a big exhaust leak at the collector, which i know is right by the slave cylinder. I saw the hydraulic line looked a little messed up (maybe from exhaust heat), so I replaced it and added 2 collector gaskets as one did nothing (still leaks bad, but can't drive it to a muffler shop yet). Drove about a mile before I was locked out again. After a little bit (maybe up to 45 min) I can shift and drive it again like nothing ever happened. The master was replaced less than a year ago. Any suggestions or ideas?