Not to be the barer of bad news, but your output splines on the transmission are about 1/3 - 1/2 way worn through. Super common on 62s once they start approaching or getting over 200k.
You may want to consider upgrading to the 1 piece main gear, or having your main drive gear welded to the PTO gear.
You may want to consider upgrading to the 1 piece main gear, or having your main drive gear welded to the PTO gear.