Commando 800 lost 1st gear, then reverse 2 minutes later

[exdirtbiker 0]

Friend of mine just gave me his 1972 Commando 800 # 1-0110.  I put a battery in and starts instantly.  I would keep her, but I already own (and gave it to my Dad) the exact same mower, and Dads was in showroom condition.

So I'm selling it. Buyer on way.  Starts instantly, moved it out front to sell it, and realized I can't move shifter into 1st.  Engine on, off, rocking... no.

Then when I restart, reverse did the same thing.

It's the 3-2   shift pattern.

           R-1

3 and 2 work fine, shift between them fine. I can pull the stick back between R-1, but not move it left or right.

I pulled the shifter, and couldn't see anything wrong, or I should say I couldn't see anything at all through the layer of brown gunk that used to be gear oil 40 years ago.

 

Am I going to have to split the cases to fix this?  Any helpful hints are welcome. I already found the manual for it here on this site.. ( Thanks ! )

 

And FYI: it was actually sold before it broke !!! it died as it was heading for buyers' trailer. and yes, I gave him back the money that was already in my pocket.

 

 

Edited May 10, 2016 by exdirtbiker

[exdirtbiker 0]

OK, after watching Steves' AWESOME video, I really need to know : 

 

How do you get all that junk off the gears so you can work on it without swimming in goop?

 

And, more importantly... are part available for these?  After looking at the manual, I don't think "2-36" is really the full part #.

[Racinbob 11,257]

You have a 5085 transmission. The '2-36' isn't a part number as you suspected but this will give you what you need.

The first thing you need to do is flush it out. A lot of guys use diesel fuel. Drain the oil and add the diesel. Drive it around a bit then drain again. Repeat if needed. Do this and then get back to us. It sounds like your problem is in the shifter fork/rails. It could be as simple as the excessive 'goop' in there but let's not rewire the house if it's just a burnt out light bulb.

[stevasaurus 22,883]

Do what Bob said...but I would do it with the rear end on blocks.  1)  If you have a leaky seal, you will not leave a trail on your lawn.  2) If the rest of the trans decides to lock up, you won't have to push it from the farthest corner of your yard...if you can push it.  3)  If the trans starts too make noises like you are destroying it, you can easily shut off the engine and maybe not do any damage.    You may want to jack up the front end also, to level the tractor.  Actually, the front end should be higher then the rear to drain better.  Drain out the old oil first, add 2 quarts of diesel, run at half to full speed in either 2nd or 3rd gear for about 15 to 20 minutes...drain and repeat if you think you need to.  That will make opening the transmission a much nicer job, if you have to.  Let us know.