Had a spare day this weekend so I decided to put the transmission back together. When I got it the top off was and I drained the water contaminated fluid and changed the reverse gear. There it has sat patiently since.
Saturday I picked up 6 gallons of SUDT2 for $130 which was about right. I started by popping all the drain plugs again and more milky watery oil came out of all three. It's had almost a year and a half to collect more water and drip down so little surprise there. Above are pictures of the drain plugs and the level plug on the left side of the transmission.
After draining I went about reinstalling the hydraulic pump and lines. Before bolting them down I used one of my squeeze bottles to fluid clean fluid through the lines and pump. I had a little trouble getting the bracket on the take off block to line up but a little strategic bending with a screw driver and rag sorted it out. The pump went back on without too much fuss though I have no idea how I managed to get at those two nuts on the far side before. I happened to have a set of metric crow's feet that did the trick this time (I don't remember using them taking it off). It was obviously intended that you remove the offset piece from the block before removing the pump.
Once the pump was bolted up I added about 3 gallons of fluid to the sump, squirted some more fluid into the pump and attached the lines.
Next I cleaned the crud off of the shifter fork plate and attempted to test fit it. I spotted a problem right away. Some idiot had snuck into the barn while I was away and put the reverse gear in backwards. The nerve!
So I removed the plate that locks the reverse gear shaft and right here is where my day started going wrong. FYI to anyone changing the reverse gear there is a right and wrong direction to push the shaft. The front of the shaft is home to an oring that is likely to be hard as diamond after all these years and is nearly impossible to push the gear over. It took a 3ft piece of pipe levered through the steering box opening just to force that shaft and that oring rearward. It took 30 more minutes of similar fussing before I managed to pop the gear off the shaft, minus one of the bronze bearing sleeves....
I then made the brilliant deduction that I'd done it wrong, pushed the shaft back the correct way (forward), removed the sleeve and pushed it back into the gear. Then I couldn't manage to get the gear back onto the shaft mostly due to lack of finger room. I managed to drop it several times into inches of murky transmission fluid. The best time I managed to drop it just right and it wound up at the very bottom of the transmission trapped underneath the main shaft. The only way it will fit in or out of that space is by rotating it such that the shift fork groove is touching the main shaft as it moves up or down. I couldn't get my hand down there and the coat hanger I had been using couldn't grip it properly get the gear back up. I was fairly certain I was going to have to remove the transmission and main shaft so I could get the gear back.
Luck would have it though my mother had one of those gripper arm thingy's from when she had a hip replacement and that proved to be my salvation. It had just enough grip to grab the teeth and slip it back up above the main shaft.
Crisis averted! I then attempted to test fit the forks again. Somebody found a dial marked "Challenge" somewhere in the barn and turned it way up. No matter what I did I couldn't get the reverse fork to fit in it's groove on the gear. I spent another half hour fiddling, cursing, and chucking wrenches through the wall and finally came to the conclusion that the groove was narrower than the fork. I couldn't get my calipers down there though so there was only one way to confirm that....
Uh huh well at least I was right. Here is what I measured.
Original Gear - New Gear
Old Groove Minor Diameter 1.135"
Old Groove Width 0.276"
New Groove Minor Diameter 1.015"
New Groove Width 0.265
Dist b\t Forks 1.150"
Fork Width 0.270"
There's plenty of clearance between the forks and the minor diameter on both gears but where as on the original gear gear there was a +0.006 width clearance there is a -0.005 width interference with the new gear. Apparently there is a bit of a quality control problem with who ever makes these replacement gears. I believe I got this gear from tractorpartsasap.com but I'm sure they got it from the same supplier as a bunch of other after market parts dealers so beware.
I thought about trying to turn the groove a little in the lathe but I didn't have any stock large enough to make a holder for it. The only other option was to narrow the forks a bit. They are hardened so I could only dull my file on it. Then I remembered my wet stone and sure enough the rough side cut quite well and fairly fast. Keeping the stone across both forks as I cut kept the two surfaces on each side parallel but there was nothing keeping the two pairs of surfaces parallel with each other. I played that one by feel and they stayed within a thousandths of parallel so I was pretty happy.
I took about 0.003 off each side and it fits like a glove now. I'm a little worried the fork was only case hardened and I burned through that to the softer core metal but only time will tell if it's going to wear out rapidly. The fork is (relatively) easy to change if it comes to it later on.
