TYM T273 Moves backward but not forward. Help!

[Bob Nelson]

I have a TYM T273 with 700 hours on it. Everything worked fine until I changed the hydro oil.

I changed the oil and filter (WIX) and forgot to clean the screen. I used it to cut the grass but noticed that in high it would whine and have pedal resistance. So, I cut the grass in low. So, I tried H again and it had a lot of noise and pedal resistance. Would hardly move.

I thought it could be a clogged screen so I drained the oil again and pulled the screen out and it had some red fuzzy stuff on it. Not much and no metal. Cleaned it and replaced the screen. New Mobil hydraulic tractor fluid for hydrostatic tractors. (first time used TS Premium hydraulic fluid).

Only very slight movement in L and virtually none in H. Noise and resistance and I notice when I push hard on the pedal and let off there is like a sudden pressure release as though it is blocked somehow.

Reverse works perfect! H or L. No noise at all.

Any ideas? I have ordered the TYM filter thinking that somehow on the change the WIX might be too fine of a filter and it's blocked. But reverse is fine.

 

[kb12610]

I have used the WIX and TSC Premium Universal with no problems. Only time I have ever encountered anything like this is when the parking brake did not fully release.

 

[Bob Nelson]

I used Mobil Delvac, not the 424 fluid. Now I'm changing to the Premium Universal Tractor fluid sold by Lube King. Looks to have similar characteristics.

Going to change it out when the filter arrives. Changing the screen for a new one as well. But, something is really amiss as now when I step on the "forward" pedal nothing at all in either H or L. Reverse still works fine. I have no idea. Do you know if there is a separate pump for forward and rev

 

[kb12610]

Have you looked at the pedal linkage underneath the tractor. Make sure nothing is binding or come loose. I do remember getting a stick or piece of wood wedged in there one time that gave problems. It limited pedal travel. I believe its on the forward pedal linkage, there is a shock absorber dampener that could be a possibility. Would have to look at the parts manual on the two pump question but wouldn't think that would be practical. I would start with the pedals and work in to something internal.

 

[Bob Nelson]

I checked the linkage first thing. Nothing amiss that I can see. I'll be taking the deck off, jacking the tractor up for a closer look. Will report back.
I still do not understand how the hydrostat actually works. I am assuming the pump pressurized the hydraulic motor and reverses direction to go backward. But, why back and not forward? Once I drain and inspect the parts perhaps I will have a better Idea. I have never run in to a problem like this on my other hydrostat tractors.

 

[kb12610]

Try disconnecting the dampener and see it that effects pedal travel.

 

[Bob Nelson]

I checked the linkage. Looks good. The pedal just going down without any action was because the bolt was not tight enough on the shaft which controlled the valve going from forward to reverse. Still no movement forward. I drained the hydrostatic trans fluid, put in the new screen and there was what looked like small red flakes in the oil about the size of a grain of sand. On further examination this material is easily smushed with my fingers. Perhaps paint from something?

I contacted WIX and they said they have NO filter which meets the specs of this tractor or the Mahindra which uses the same tractor. I found out from the manual that the specs are minimum size filtration is 25 microns, not the 17 which the WIX 51586 which some have used. He also told me there are other factors other than the microns and fitment apparently some design features which are different based on pressure and flow. Still waiting for the filter to arrive and see if there is any difference.

I also contacted a Branson dealership which sells TYM/Mahindra parts and she was very knowledgeable. She said the have had Baldwin filters collapse so don't use them anymore. She told me that the 2 non-TYM filters they use are Fleetguard and Donaldson. She was very familiar with the micron issue. She was out of stock on all 3.

I also contacted the Mahindra dealership about 10 miles away and the parts guy spent a lot of time looking up the hydrostatic filter number I gave him. Finally found out that it was/is used on older models. Couldn't get the correct filter. He also said the best TYM/Mahindra compact/subcompact tractors using the Mitsubishi engine are the best.

Still do not know about whether the filter is going to help. Seems unlikely that it would go reverse, but not forward. However in waiting I have removed the WIX and looked inside, drained it and full of this red stuff. I put it back on until the Mahindra filter arrives, so we shall see. I will update as I learn more.

 

[TYMinColton]

"The pedal just going down without any action was because the bolt was not tight enough on the shaft which controlled the valve going from forward to reverse. Still no movement forward."

I'm a little confused by this. So, was the pedal not connected, but now it is? I ran over a log a few weeks back and it bent part of the linkage assembly pretty badly. I was able to push the left pedal and go forward, but the right pedal was was physically restricted due to a bent part underneath. Once I straightened things out both pedals worked fine. FWIW, the part that I bent was the shaft that attaches to the odd shaped roller on part 27 in attached diagram. I don't remember the details, but one pedal has to "ride" over the other pedal with a bearing. If anything gets out of alignment or is damaged the two pedals can't move up/down relative to each other and in my case this prevented me from going backwards. There isn't a good diagram out there showing how the two pedals interact, so it took me a bit to figure out what was bend and out of alignment. Hope it's this simple in your case. . .

 

[Bob Nelson]

I raised the tractor up. Removed the rear wheels. Checked the linkage thoroughly. There is a shaft that comes out of the hydrostatic transmission which a flange attaches to. There is a pinch bolt and it was loose. I tightened it up. Absolutely no resistance when rotating forward. In reverse, there is resistance and the tractor moves in reverse in H or L. I finally contacted the TYM dealer near me. He has very good reviews. He is checking it over but the hydrostatic transmission is not serviceable as far as disassembling it and repairing. It is a $3,000 part and if bad it needs to be replaced. Not good. Not much else I can do at this point. Thanks for your help! I will post results.

 

[TYMinColton]

I'm sure you've got this covered, but there is a bolt just above the linkage that you turn to adjust creep. Just a slight adjustment on this bolt and tractor will roll forward or backwards on its own. I'm being dumb here, but you didn't tighten down this bolt did you? Anyway, I feel your pain. Totally sucks. Really not serviceable? That's a bit surprising. Might cost you more in labor to repair than replace, but I would think its serviceable. There's a full breakdown of the transmission in the service manual. Wishing the best of luck. . . hopefully you can figure out what happened, so it doesn't happen to the rest of us.