Have a 231j (4cyl) that I have put an sye on years ago but had it grind sometimes only in 4high, I then put the savvy cable shifter on and rebuilt it with all new bearings and a wide chain. Since then my 4low will pop out of 4low and begin to grind (yes the cable shifter is set properly and stays engaged in 4 low when this happens till I have to take it out of 4 low to reset the case gears and often times it’s very difficult to do so) I imagined I put a snap ring on wrong where the shaft moves disengaging the 4low just enough to still grind the gears but not grab them. It only seems to happen on steep climbs or when I’m putting a lot a torque down. I have the case now disassembled and trying to find the problem but can’t see anything out of the ordinary. The main output shaft seemed to have more play in it that expected but as far as snap rings I can’t see anything causing this, could it be the wide chain interfering with it ? When I put the shaft in as if I would be closed the chain binds a lot and it seems like it needs to sit 1/4in taller than it is.
