Small Engines (Lawn Mowers, etc.): John Deere 420 front end, cotter pin, castle nut

Question
My front end is out of whack. The axle is shifted forward...putting the sheaves and belt out of whack. I jack it up, and it pops back into place, but as soon as any weight is put on, it snaps back out of whack. It seems like there should be a pin or bolt to hold it in place?

Answer
Yes there should. There is a 1" bolt that goes through the frame and I-beam.  Rarely do they break but I have seen it.

Usually they just need tightened.

Pull off the grill and you should see a big castle nut with a cotter pin in it.  Remove the cotter pin and tighten the bolt as tight as you can.

If you don't have a bolt and cotter pin showing the only thing holding your axle in is gravity. Buy a bolt. Go to the dealer. It's not an ordinary bolt