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thedaddycat

Transmission bearing depth in case

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thedaddycat
OK all you tractor gurus out there, here's one for you.... the parts manual for my 3310 shows a 1/16" clearance from the inside surface of the case for the 1st intm. shaft bearings with the rest of the bearings flush to the inside of the case. My question is this, do the bearings move farther out when the cover is bolted up? If so, is this to ensure minimum end play in the shafts? I will have pics tomorrow to illustrate what I'm talking about.

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thedaddycat
As you may recall, I blew out the bottom BGB bolt holes and was making support plates to bridge the frame to BGB area. While I had things apart to take these preliminary plates off..... I decided to check out why I was having trouble shifting. Considering what I knew about already, namely the large repair to the transmission case, I'm glad I went all the way with this one... I probably should have taken it apart in March when I had the tractor down to bare frame, but if it ain't broke I usually don't go fixin' it and it wasn't giving me trouble too often. The problem turned out to be a broken shifting stem due to crack propagation. Looking closely at the break it looks like a central band of material had been holding it for a while because the old parts of the crack were not clean and grainy but had rubbed against each other. I also found a snap ring on the 2-R shifter shaft instead of the required retaining ring. The snap ring was deformed and cup shaped. The roll pin in the case that forms half of the shifting stem "gate" also had a spiral crack in it, though it was still firmly in place. There was more fun yet to come from this area, but that comes later.... As I read through the Repair Manual I noticed that only one set of bearings had any recess(1/16") from the inside machined surface of the case or cover. This was far from the case here. Three bearings were installed incorrectly and none were set to the right depth. On top of that, when the repair was made to the cover the bearings were never removed. Two of them wound up in the heat zone of the repair. The pencil points to one of several small cracks in the cover, possibly from stress due to the heat of the repair? The reason I was asking about the bearing depth is because of some other things I found. One of the washers had worn down so thin it looked more like the blade for a tubing cutter. The drive gear also looked like it was offset to the cover side by about 1/2". Note the gap between the axle tube spacer and the drive gear, and the wear mark on the axle tube after I drove the gear back(to the left in pic) until the snap ring seated in the recess of the axle tube spacer. The(right side) washer with the key notches then could engage the drive gear keys. Both sides had the bearings recessed quite a bit. Could this allow enough end play for the drive gear to creep along the shaft over time? In any event, I pressed out the bearings and cleaned them. I then reinstalled them correctly. I am getting all new oil seals from Jack's along with some other stuff like washers and a gasket. I will post more of this saga later, but it's bed time for me. One more night shift to go......

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thedaddycat
OK then, back to our story.... Upon taking all the shafts and gears out(BTW they don't just come apart like the book says if they're messed up this bad...) I discovered that the R-2 pinion gear assembly had been welded to hold the two gears together. The result of improper welding/tempering was that the collar that engages the shifting fork was embrittled, most likely from cooling too quickly relative to the rest of the gear....... and it too cracked and was part of the problem with difficult shifting. It snapped all the way off when I tried to tap it back in place. Though it could probably be repaired properly, I will get a new gear since the gear teeth have a bit of wear. I will also be replacing one shaft and all the keys. Of interest also is the crack at the end of the keyway on the case side of the axle tube. When I saw how much damage had been done and how poorly the repair was made, I was amazed that this machine has held up so well. I theorize that the tractor was not properly secured in a truck and that it fell out the back and landed on the right rear wheel. There is no way to tell how the axle tube was aligned when the damage happened, but this would explain the right(cover)side being blown out and the counterforce being exerted on the opposite side of the transmission case. It would also tell the tale of keys and keyways stressed to the just-short-of-failure point. How about it guys? You have the pics and the story. I welcome all commentary, ideas, and suggestions..... After opening the transmission case, I knew I had to put something into it if I wanted to use the tractor the way I intended to. I will probably use the transmission cover off another gearbox, and I'm debating getting all new bearings too.

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Dutch
Kirk, The one repair to the case looks like braze NOT weld. Brass will fail before cast iron. From your excellent inspection, I would consider a replacement transmission. A good used original unit may be better than any repairs will ever be to yours (cheaper too).

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roma3112
i would tend to agree with dutch. I too have had a similar saga in regards to a similar unit that i helped my neighbor fix. He was determined to "keep it all origional" well several hundred dollars in parts, (not to mension time) he still had the same problem, Out of frustration and aggrevation he swaped out the unit as soon as i came across one in my travels. It sounds to me that this tranny was pretty well hacked up, consider a used unit, many people here may be abel to help you locate one. john

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thedaddycat
I have three 725's and a 9 HP Landlord from which to choose a replacement cover and/or whole gearbox. I wll look at the Landlord first since it's the least complete. Still, this demonstrates the versatility and durability of these tractors.... if you are looking to rid yourself of one of these beauties( a 3300 series), please let me know....... Dutch, yes this is obviously a brazed repair but I'm not sure the heat of repair didn't contribute to problems. The cover is clearly warped at least a little and has to be pulled into alignment by its bolts in order to seal tight to the case. Thanks for your help. Kent, please feel fee to use any and/or all of my posts in the DIY section ..... Thanks again to Kent the Provider for the opportunity to contribute to our collective mutual benefit. Keep up the good work folks.....

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