MM BG or BF drive shaft

T.R.K.

Well-known Member
Deep into repairing transmission and drive shaft on a MM BG (MM BF would be same shaft) I may be over thinking this, but the drive shaft has universal joints on both ends and goes through the torque tube from the clutch housing to the transmission. I just pulled the whole shaft out with the transmission. I had to get it out. It appears the front U-joint at the clutch housing was the problem. It was about to twist apart.

The big question now is how do I get it back in there with U joints on both ends? Or am I over thinking this? I mean, I know it had to be assembled this way somehow when assembled new but how did they do it? Any thoughts will be appreciated.
Thanks! T.R.K.
 
Merry day after Christmas and I trust my comments will be of some help.

I replaced universal joints, clutch, throw out bearing, and trans seal on my BF project several months ago. It's a real fun project best accomplished by someone with small strong fingers and good eye sight.

According to parts book only 3 3/16" x 2-1/4" cotter pins are used to hold shaft in place. 2 pins would hold universals to shaft and the third to the trans input shaft which will be installed right before final closing.

I started reassembly by blocking tube in position about 6 inches to rear of clutch housing. Insert shaft assembly through tube and connect front universal to clutch shaft making sure everything is lubed and slides easy. Do not install cotter in front hole. Now slide tube forward and fasten.

Next bring rear trans assembly forward [I used a com a long] to about 1 inch from final position. Carefully lift, align cotter holes and slide universal joint onto Trans impot shaft being careful to only slide about 1/2". You want to just start this connection. Caution; If you move shaft too far, front universal will drop and you can start over. With both shaft ends started you can now bring back end forward and start fasteners.

Working through inspection holes, use a sharp pointed object to align and install rear cotter. Good Luck.

Hope this helps,
Dan

Warning: I'm going to need some assistance on my family 1939 MM R engine noise challenge.
 
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Thanks for replying. Right now I just have the transmission off the rear of the frame. I was really hoping not to have to un-bolt and move the torque tube. So I guess I am doing mostly what you did, just from the back end.

It looks to me like the big issue in my case is getting the front univeral spline back up onto the clutch shaft.

Are you the one who gave me part numbers for the universal crosses? If so, thanks for that too.
 
Thanks for replying. Right now I just have the transmission off the rear of the frame. I was really hoping not to have to un-bolt and move the torque tube. So I guess I am doing mostly what you did, just from the back end.

It looks to me like the big issue in my case is getting the front univeral spline back up onto the clutch shaft.

Are you the one who gave me part numbers for the universal crosses? If so, thanks for that too.
Yes, I gave you the part numbers.

The bell housing and entire clutch assembly can be removed via rear after everything is cleared out of the way and you follow the book.

Before you remove the torque tube, try this dreamed idea. Clean and lube the splined clutch shaft. Using wood blocks build up a bed in torque tube to hold shaft at just the right height so that with a lot of skill and luck, you might be able to slide joint on to shaft. I hope it works for you.

Good luck,
Dan
 
Thanks for replying.
The tractor in question is a BG. It differs from a BF in that the steering shaft support is bolted to the torque tube. I was hoping to leave everything from the torque tube forward assembled to the frame and just remove the transmission from the rear of the frame. (So far this has gone well, I put new bearings back in the transmission and it is ready to go back in. The front universal cross had worn through the hardened cups, and was working on the yoke iteself, and was just 'before' totally twisting apart. Fortunately I had a shaft from a parts tractor that showed up here about 20 years ago to rob a yoke from. I did have to ream the yokes to fit the SKF crosses. And I had to spread the yokes a bit too, but I probably crushed them when pressing the old cups out of the yokes.)
The issue I am trying to fix is it was making a "ting ting ting" in the driveline when not loaded. This was worst in third gear, for some reason. Nothing in the trasmission seems to be very bad except for some chips in the differential pinion. I don't have another one, so its going back together on the assumption that the drive shaft was the main failure.
I got the drive shaft together today and spend the last hour and a half doing about what you recommended. The only difference from what you suggested is I used a piece of 2" channel iron to slide the drive shaft in instead of a wood block. I could see the rear of the clutch shaft pretty well from underneath at the front of the torque tube.
About 1-1/2 hours later and several (many many) tries, the front universal finally slid up on the clutch shaft about 1/2 inch. I think it will go the rest of the way, but I was out of time for today and I think the next thing to do is to bring the trasmission up to the rear of the shaft and start the transmission shaft in the rear drive shaft yoke.
If you ever do this, tie down the clutch pedal so the clutch shaft and turn. In hindsight, it would probably have made re-alignment easier.
So far I have about 11 hours in this repair and hope I will have it back together by Thursday.
 
Glad it really worked. While a hour and a half sounds long to slip a universal on a shaft, you would have spent twice that pulling the torque tube and reassembling.

Dan
 

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