Tractor Repair: 1086 Front Pinion Bearing, electric frying pan, output shaft

Question
Hi Arnie, I have a 1086 speed transmission in bits at the moment and noticed the internal bearing surface on output shaft that mates to front of pinion shaft is worn and has corogates in it - any idea what mite cause this or is there anything i should check? Have got a new output shaft to replace it but feel it would be best to change matching bearing at same time - so can i change the front bearing on pinion shaft while it is still in rear housing? Service manual says to hold weight against pinion gear while tapping new bearing on but didn't want to have to take top off rear housing just for that if there is another trick? Many thanks Rob.

Answer
  Sorry, there is no way for me to know why this may have happened.  Sometimes, bearings just fail even though they run in oil all the time such as inside a transmission.  You've got the right idea, it would be foolish to change the shaft and not the bearing.  They should both be replaced at the same time.  I agree with you about removing the top cover of the rear housing.  I would avoid having to do all that extra work if possible.  A much easier way is to heat the bearing before installing it, so that it will expand and slide right on without having to drive it on.  For applications where it is impractical to drive a bearing on, we use an old electric frying pan with transmission oil in it to heat bearings to about 300 degrees F.  After heating the bearing for about 15 minutes, remove it from the pan with a large pliers or tongs and install it on the shaft and let it cool off.  As it cools, it will shrink onto the shaft and fit tight again.  Don't try to heat it with a torch, it's too easy to overheat it in certain areas which will damage the bearing.  Of course, this procedure can't be used on certain bearings with a plastic cage for obvious reasons.