QUestion about transmatic drive/transmission etc

2stroke1971 · Jul 27, 2018

Ive got an older MTD with the transmatic drive system. 14.5 briggs IC engine. Bought it cheap and got it running. Would not drive though. I went through the "reset" procedure as far as the instructions on the mower hood, no change.

It made some banging noises in gear at one point. And after going through the reset, it actually did "Catch" and lurch forward and move a bit, then I hit the brake pedal to stop it. couldnt get it to move again. For what its worth, I am an industrial mechanic.

It came with a full set of new belts. Tonight, I watched a video about how the transmatic system works and I went and pulled the covers to check mine out.

The belts there are not horrible, not broken anyway. The deck belts are sloppy, but to my disapointment the belt that went back to the differential looked ok to me.

I pulled the belt to the diff. off and I was able to spin the pulley on top of the diff freely with my hand around and around, no drive action so to speak, no meshing, no trying to spin the rear wheels.
Does this mean the diff is bad? , is there any type of centrigugal action on the diff, that is to say does that pulley have to be spinning at some minimum RPM to make anything happen or is this thing just done? OR is there a definitive way to test the diff?

Thanks in advance for any input!!!!

Boobala · Jul 27, 2018

I'm thinking you might have a variable speed pulley type transaxle with a "variator" when you step on the forward pedal harder, it goes faster, in any case get under the mower and see if you can see a data-or ID sticker and does your mower have a setup similar to the enclosed pic.....

...

..... click to enlarge

2stroke1971 · Jul 27, 2018

Thanks for the reply. Mine doesn't have a forward pedal. The " gear selector " alters the tension on the variator pulley and theres a brake pedal which releases the tension on that same belt regardless of which 'speed' you have selected. I'll try and find an id tag later when i get home and post it.

shiftsuper175607 · Jul 27, 2018

2stroke1971 said:
Thanks for the reply. Mine doesn't have a forward pedal. The " gear selector " alters the tension on the variator pulley and theres a brake pedal which releases the tension on that same belt regardless of which 'speed' you have selected. I'll try and find an id tag later when i get home and post it.

Does it have forward/reverse neutral?
Check that linkage from shift lever to transmission...especially at the pivot on the transmission end.

2stroke1971 · Jul 27, 2018

Yes, it does have forward neutral reverse. I will check that out as well, i guess if it was in neutral that pulley on top might freewheel like that huh?

2stroke1971 · Jul 28, 2018

Well.....
the tranmission was in neutral after all, hence the free wheeling pulley on top. The shifting action is a little hinkey... Ill work on that. with things running and spinning, I bet it works better. No linkage adjustments, just a pivot point.

Still this did not explain my not being able to drive, it wasnt stuck in neutral after all. (I should also mention that although I lowered the deck with it running, it didnt cut a bit, the blades were not spinning very much.)

In anycase, moving on, I went on through the process of replacing belts. The drive belt actually looked very nice when comparing it to my new belt. No smoking gun there.
The engine pulley to variator belt also looks like it has very little lto no wear, although I have not removed it yet.

I got set to try and remove the engine pulley and guess what? The pulley spins on the shaft! I havent loosened the bolt yet. I can hold the shaft still with the ratchet on the bolt, then take the belts by hand and spin that pulley around
without the engine turning over.

Heres my smoking gun, why it would not drive AND not cut....the engine pulley is slipping.

I just did some searching and there is a keyway....someone left the pin out or it's sheared completely. I only have metric impatct sockets at home, gonna run and buy a 5/8 so I can get the pulley off.

Im gonna back up and tell the story I got told about this mower.....the guy I bought it from got it from his neihgbor who stopped using it.The guy I bought it from had bought new belts for it. So while he assured me the engine would run, I bet he knew it would not drive. (So he probably went out and bought new belts, but never got around to the job)

GIven the condition of the belts on there, Id almost bet the original owner put a set of belts on it, and left the keyway pin out. Frustrated, he gave it to his neighbor who bought a new set of belts for it again, but never installed them....2 years after that I bought it.

I love a good mystery. Its as much fun for me as fixing stuff----trying to figure out what went wrong!

So, not pleased the engine pulley is slipping, but happy I found a reason for it's symptoms.

Boobala · Jul 28, 2018

2stroke1971 said:
Well.....
the tranmission was in neutral after all, hence the free wheeling pulley on top. The shifting action is a little hinkey... Ill work on that. with things running and spinning, I bet it works better. No linkage adjustments, just a pivot point.

Still this did not explain my not being able to drive, it wasnt stuck in neutral after all. (I should also mention that although I lowered the deck with it running, it didnt cut a bit, the blades were not spinning very much.)

In anycase, moving on, I went on through the process of replacing belts. The drive belt actually looked very nice when comparing it to my new belt. No smoking gun there.
The engine pulley to variator belt also looks like it has very little lto no wear, although I have not removed it yet.

I got set to try and remove the engine pulley and guess what? The pulley spins on the shaft! I havent loosened the bolt yet. I can hold the shaft still with the ratchet on the bolt, then take the belts by hand and spin that pulley around
without the engine turning over.

Heres my smoking gun, why it would not drive AND not cut....the engine pulley is slipping.

I just did some searching and there is a keyway....someone left the pin out or it's sheared completely. I only have metric impatct sockets at home, gonna run and buy a 5/8 so I can get the pulley off.

Im gonna back up and tell the story I got told about this mower.....the guy I bought it from got it from his neihgbor who stopped using it.The guy I bought it from had bought new belts for it. So while he assured me the engine would run, I bet he knew it would not drive. (So he probably went out and bought new belts, but never got around to the job)

GIven the condition of the belts on there, Id almost bet the original owner put a set of belts on it, and left the keyway pin out. Frustrated, he gave it to his neighbor who bought a new set of belts for it again, but never installed them....2 years after that I bought it.

I love a good mystery. Its as much fun for me as fixing stuff----trying to figure out what went wrong!

So, not pleased the engine pulley is slipping, but happy I found a reason for it's symptoms.

Strange ... keep us updated ......

tom3 · Jul 29, 2018

I like that drive system a lot. No Chinese hydro throwaway junk to let you down after a couple hundred hours. And you still have the variable speed. Need to check on the VS pulley action every now and then, make sure the discs move as needed to change the pulley pitch/diameter.

tom3 · Jul 29, 2018

Some pictures?

2stroke1971 · Jul 29, 2018

Got the pulley off. Its wiped out, no keyway left and egged out the opening. I had the same thing happen to the harmonic balancer on one of my son's Honda Civics.
The shaft looks ok, the keyway is a little dinged up but will be ok. The pulley bolt got damaged as well, I hope the threads in the shaft are ok.

Right now, Im looking at a new pulley, bolt, and maybe a tap to chase the shaft threads with.

I work alot, I changed jobs after having the same one for 24 years, and I find myself going back to the old place part time. Both places are busy now, so I only get little bits of time to work on this thing.
Thank you all for the input!! I will update when I get back to it, but it may be a bit.

I replied again with some pics!

QUestion about transmatic drive/transmission etc

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