M-9540 pops out of second gear

[The Hayman]

Hi,

I have a Kubota 2007 M 9540 (w/cab) that I purchased new. It recently started poping out of second gear. A bit less than 4500 hours on the machine. Local guy known for his wizardry removed the transmission cover and inspected. Everything looked new. Put it back together but then it was very hard to take out of second (needed a hard wack). We puzzled for awhile and then replaced the 1st/2nd gear shifter rail, 2nd gear shifter fork, and detente springs and balls. Shifts smoothly now but still pops out of second under load. Any ideas? This has been a good tractor, tend to think we are overlooking the simple.

Thanks

 

[Kingfisher]

It's probably what they call the sliders or the dog teeth. I don't think you can replace without disassembly. Does it stay engaged if you put pressure on the shift lever?

 

[The Hayman]

It pops out at random times, so I have not held my hand on the lever to try to hold it in place, but will try (just got it back yesterday, and tried it this morning with one trailer of 11 round bales pulled through some snow). The parking brake lever is part of the shifter assembly. In the past it appeared to wear and I was able to put her in gear while in park. I fixed this with a shim that held the parking break lever further from the shift lever, which returned the lock function. I noticed when I tried the tractor when she was hard to take out of second that I was able to put her in 3rd and 4th when in park. This has me wondering if something in the linkage is worn, loose, or damaged, and she is not fully in 2nd, or moves partially out of gear when underway, but this does feel like wishful thinking, but it may be the next place to investigate?
I do remember my older brother had a 1967 VW van that poped out of third. He fixed it with a bungee cord tied to the dash that was hooked to the lever when in third. It worked, but I am really hoping I can find a better better solution at a bungee cord price.

Thanks