200 Jumps out of 3rd gear

 Can someone please tell me what causes the 180,185,190 and 200 to jump out of 3rd gear when going down a hill or backing off on the throttle ? Will a new shift fork usually correct the problem ? Does the tractor need to be split to repair this condition ?

The transmission on my 190XT is currently in pieces for this reason - jumping ouf of 3rd and 4th.  Found several little things that contributed to the problem.  Main problem:  Shift fork for 3rd/4th was really worn bad.  Bought a new one from AGCO - but NOT cheap!!  Also found that the bearings on the input shaft were not very good, and allowed the input shaft to move back and forth.  The splines on this shaft were not the greatest either.  Managed to find a good aftermarket unit.  The shift linkage itself could also have lots of wear that does not really help matters. Since it is apart, I am also replacing every bearing and seal in the transmission and rear end.  Should be good in the end! It is important to note that this problem is derived through abuse by the operator.  Use the clutch and don't grind the gears and you'll be fine.

We split our 180 last year and replaced 3rd, 4th gear, and reverse was worn and so we put in some shims and it works great now, now reverse is okay. To replace reverse  you have to take the rear end all apart to replace reverse I believe. We then split behind the engine and replaced the clutch and release bearing.