Did you ever find the issue with your 4035? Is there a clutch pedal free play adjustment? I am having an issue all of a sudden with mine where there is a delay when I engage the clutch before the tractor actually starts to move.
Well, I wanted to finish up this mini saga for future reference. The diagnosis was not pretty and the cure was not cheap, but$1888.00 later a couple of gears, a shift fork and a bearing inside the HST have been replaced and it now does not pop out of 4x4 any longer. After speaking with the tech...
I have a 2007 BX1850 that will pop out of 4wd when it gets in a bind. When I say "bind", i just mean that the tractor has to pull hard like with a box full of material or about anytime a good load is taxing the engine. I've searched the internet and this forum looking for information on this...