8 speed 103907 312-8

["Manic-Mechanic" 1,195]

Hello,

     I have been having trouble with getting stuck between gears and freezing oil! I removed the panel, removed the long 1/4 20 set screw and pulled the shifter out. I can only see one of the shifter forks? I guess the whole rear fender will need to be removed in order to see correctly into the transmission. The angle with the fender in place prevents me from seeing around enough to locate the other fork and align them to reach neutral! I even poked my finger around trying to locate the other fork, couldn't locate it. I removed the drain plug and nothing came out, really strange? My best guess is it is frozen. This week we should be getting warmer weather so I'll fire up the stove in the garage to melt whatever is in this transmission? Ha ha ha! I thought I like the 312-8 as it is a nice looking machine when fixed up. However, this machine is strange, the clutch is slightly different and the deck lever assembly is falling apart. 225.00 is a decent price even just for the drive train alone. Anyone have this happen to the gears on a 8-speed? The shift rod-donut is fixed in place correctly too.......

Edited January 12, 2018 by Oldman

[WHX?? 49,182]

If you can see one fork you should be able to see the other even with the fenders in place. If this horse sat out side neglected I would pull the tranny out and apart for a full inspection. Especially if nothing came out but yes that might mean just frozen. Get it warm and see what shakes. You might have a brown welded shift fork. You might get away with a liquid tune up (flushing) but it's no substitute for a full blown take apart.  

["Manic-Mechanic" 1,195]

I was driving this tractor daily. The oil was contaminated pretty bad. I should be able to see the other fork but I can't? There is no way to look straight down into the transmission. I know it is frozen and will be thawing it out, doing a flush. Even if I do pull it, the flush won't hurt. I had this trouble with it getting caught between gears two or three times already, this time it is really stuck! Ha ha ha! I plan on tearing it apart and doing a refurb., maybe it is getting close to that time........

 

 

Oldman

[wallfish 17,084]

30 minutes ago, Oldman said:

I had this trouble with it getting caught between gears two or three times already

 

This can be caused by

a worn shifter, the ball on the end of the shifter or loose doughnut piece where the dog point screw holds it

Loose dogpoint set screw

 

The forks should form a square opening when in neutral. Use a screwdriver through the hole to try and find the one you can't see. It should slide back to neutral.

If your trans is freezing it's because there's water contamination in there. Oil doesn't freeze solid.

[953 nut 55,860]

4 minutes ago, wallfish said:

The forks should form a square opening when in neutral. Use a screwdriver through the hole to try and find the one you can't see. It should slide back to neutral

["Manic-Mechanic" 1,195]

Excellent feedback,and the ball on the shifter has some flat spots, I have another one which I'll check out this morning. It's already 30 outside, so looks like a warm day is here. Great picture there 953 nut!

 

 

Oldman

["Manic-Mechanic" 1,195]

Hello,

     a little progress report:

                               The shifter does have four flat spots all the way around. The oil isn't oil anymore! I drained the gas and fired up the old boxwood stove.I got the shop very warm and then used a heat gun for a little "boost". The ice thawed and the sludge began to "plop" out! I filled the top of the first pan and then started on another. The forks finally aligned and neutral was found.Now a good flush would be nice before I add the new oil 90-140. What is the best flushing agent, kerosene? I usually use this for everything.......

[wallfish 17,084]

9 hours ago, Oldman said:

What is the best flushing agent, kerosene? I usually use this for everything.......

Kerosene or diesel for flushing it.

Probably a good idea to get a new shifter boot as that one you have is beat. That's how the water gets in there.

["Manic-Mechanic" 1,195]

Ya,

   I ordered the cover with the replacement shifter rod. The flats on the ball end of the old rod certainly didn't help either........ The prior owner didn't care for the tractor at all, beat the snot outta it! She was rescued.......Oh, and the drive belt is coming up as 5/8 x 81-108501. Most everybody else says 5/8 x 82-7473, however way you round it up? I will remove the old belt and bring it with.

 

 

Oldman

Edited January 10, 2018 by Oldman

[wallfish 17,084]

Seems as though you have the shifter part well under control.

What's up with the lift lever? Your first post stated it's falling apart

["Manic-Mechanic" 1,195]

Oh, ya, the deck feels extremely heavy once up then it barely locks in place? Maybe the spring? I have yet to take that apart and see. I did take the belt cover off to see what was rattling? The old belt has many cracks so it may have been bouncing. I am just glad that there was no piston type tensioner on the idler pulley! (some of the 312-8 were supposedly built with one). Leicester aye, ever go to Worcester?

 

 

 

Oldman

Edited January 10, 2018 by Oldman

["Manic-Mechanic" 1,195]

Well, the kerosene soak didn't go as planned! I went out to the shop and seen a nice three foot round puddle under the tractor! The kerosene made it's way out of the transmission, perhaps a very bad gasket? Hopefully the case are not cracked! I do have another eight speed on a parts machine if need be, but this ruins my idea of using this tractor through the Winter for sure.......I'll run another test again tomorrow and watch for the leak, perhaps I dumped the kerosene too quickly through the shift hole and it overflowed? I always run into challenges while working on things, better now than later on.......

[wallfish 17,084]

On 1/9/2018 at 8:39 PM, Oldman said:

Leicester aye, ever go to Worcester?

Unfortunately way too often. Up here it's pronounced "Wusta"

 

Bet you may have discovered you need seals. Check input, brake and axle seals for leaks

["Manic-Mechanic" 1,195]

Hello,

      I run the kerosene through and flushed the seals and then drained the rest through the plug. Someone correct me I'm wrong? The seals prevent heavy oil from leaking but I don't believe they will prevent kerosene from passing......

Edited January 12, 2018 by Oldman

[SEA BEE 0]

can't find my drain on my c-81 does it have one it 1978

[pfrederi 17,893]

Bottom of the transaxle just to the left of the tongue of the hitch that is under the rear end.  it is a 1/4" allen plug

["Manic-Mechanic" 1,195]

Another excellent picture! Well, that is amazing because even though I know the plug is there, I always have to reach around under there to find it! I filled the transmission back up with kerosene and sat and watched with amazement as nothing leaked!

No complaints here though. Still I'll watch the underside of the transmission after filling it with the gear oil, again 90-140. Nice to have things work out for a change......."knock on wood".

 

Oldman

Edited January 12, 2018 by Oldman

["Manic-Mechanic" 1,195]

The transmission had no leaks, changed the oil, replaced the belt and rebuilt everything that was assembled incorrectly or missing parts! I put some new rubber on the rear too. Now the rear lights are needing an update as the ground isn't reaching the two fixtures, too much rust!  For a 1990 it sure caught cancer pretty good! However, I test drove it today moving some firewood and no more clutch issues!