Lawn Tractor Hydrostatic Transaxle Disengagement/Bypass Actuator - Diagnosis Part 1
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- เผยแพร่เมื่อ 20 ส.ค. 2024
- [AUDIO VOLUME REALLY LOW. TRYING TO FIX THAT] -- The transmission will not disengage to allow the tractor to be pushed. On a hydrostatic transaxle tractor, it takes more than just putting the motion control into neutral because the wheels and gears are always engaged to the hydraulic motor. This is true for most if not all hydrostatic-drive tractors, especially the small ones. A lot of these release/disengagment mechanisms are flimsy and seem like they can be easily broken. My problem seems to be either a broken valve mechanism as the inside end of the bypass shaft, or a badly worn connection point betwwen the external end of this shaft and the bypass actuator arm, to which the handle with spring attaches. It could be both issues. I can see the C clip in place but there is about 30 degrees of play in the actuator bar, so it clearly has a bad connection to the shaft .. BUT .. it does feel like it is still turning the shaft even if it is very loose/worn. It feels to me like the shaft is not acting on anything internally. There is really no rotational resistance so I cannot see how any vavle is being operated internally.
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Access to the hydro gear is by removing the rear cover (or what Sears calls the Drawbar Stretch). It is the part with the 'keyhole' that the disengagement lever goes through. There are two bolts on either side (you can see the ones on the L side at 0:27). Use a 9/16 ratcheting box wrench, etc., to remove the bolts then pull the rear cover right off. Full access to the hydro gear. Keep in mind that the disengagement rod must be pulled firmly, streting the spring, and the retaining pin set to activate the bypass.
Good luck
Paul
Thanks Paul!
thanks for the video Max, seeing what your doing was actually a big help. I can hear what your saying when the radio in my room is turned off.
My pleasure. I feel bad I have not been able to finish the diagnosis and fix, but life came along and happened and all my tractors are sitting in storage. I'll get em out soon though I hope and get back to making videos. :)
Great vid. Good job.
You will hear a knocking sound when the bypass engages and disengages.
Floorboards always end up as my tool tray too.
1:13 .. yup.
I took some of those old ones apart before and they lock up from water getting in from were the rod pole is at on the top of the transmission it drips down between the rod pole and into the transmission in will sit their an rust the shifter rod out until it locks up
If it's a cheap spicer transmission I don't think they used good seals around the rods on top the transmission and then inside it not good they made it to where it would hold water on top then until it gets inside and then those old ones are packed with black grease it's not oil that turned into grease over time its black grease the same as what's in a tube
the owner actually cut the bypass valve release bar. IT doesn't move at all any more so something is wrong with it. I can push the lever in and use a wire to hook it. I can hear a whining comming from the transmission but the mower refuses to move. Eather the bypass is bad or the pump is. The owner told me it was slowing down while trying to move it, so my guess is the pump has failed.
I'd say their bypass system on these is not a great design. And these hydros are a lot different than the much more heavy duty hydros you will find in older Wheel Horse, Cub Cadets, John Deere's and others. I think the hydro internals in them are decent for what they are and the price range .. but the bypass mechanism is just bad. I have a Wheel Horse hydro that looks like it is 10 times stronger than one of these hydros. These newer Sears Hydros are probably best considered 'disposable' .. still could be a great mower for 10-20 years .. but the older stronger ones could last forever with proper care. I've got a 1969 Sears Hydro that is of the same heavy duty quality as the Wheel Horse/Cub Cadets etc, so Sears did make em .. just not so recently like in these 1990s models.
@@maxhauler mine are past 20 years old and all still works good
I took a mine apart! The back Wheels were stuck, I got them Free up, but can't get too work, I pushed it around and will not work like supposed to? I don't know why? Something went wrong? The tractor is not mine, was given to me,
i think i got the same probulem show me how you fixed it
Never fixed mine but the plan was 1. see if I can take off the seat, tank, fenders and frame section above the transaxle (if it even comes out.) .. then access from above .. or 2. drop the transaxle .. Then once accessed: 3. Tighten it up again with the strongest loctite (requires total cleaning of oils to work right.) .. or as might be the case if the parts are worn from being loose and wont tighten up well .. 4. (last resort) .. just use a tiny weld there to secure the lever to the post. 5. (not worth it IMO) take the transaxel completely apart and replace the little shaft (if the end is worn from being loose.) Those are my thoughts on the matter. Good luck to you!
I should clarify: The pulling wire is attached to a 3 inch lever arm which is attached to a vertical shaft that enters the transaxle. The arm and post connect with a square hole. This design means that if it ever comes loose .. and I think they all come loose .. then it will quickly destroy the mating surfaces of both the shaft and the arm, especially becase everone will try yanking on it quite a lot. It is a bad design. This is why I think a good fix might actualy be to do a little welding job on it .. carefully, as there is a rubber seal around the shaft I would think. Good luck!
Please, where is Part 2? What did you have to do to fix it? My trans release suddenly quit when we tried to release it to roll into the garage for a starter problem. Seems odd to have both problems at the same time.
Hi Stephanie. What are the symptoms of the starter issue? It is extremely unlikely that those two issues are related and I'm pretty sure that aspect is just a coincidence. Regarding the hydro-static trans-axle release/bypass: I never continued my diagnosis and thus the video series, but I am pretty certain what the issue is. If you notice in the above video at the 6:34 mark where a green
arrow appears: This is pointing to the top of a shaft which is aligned vertically and to it attaches an arm which rotates in the horizontal plane, pointed towards the left side of the tractor. The lever (wire) you operate in/out on the rear of the tractor is attached (with a spring in-line) to the end of this rotating arm. Where the arm attaches to the shaft, it uses a rectangular hole in the arm, fitted over a rectangular part on the end/top of the shaft. A screw secures the arm to the shaft. I believe that the actual problem in most cases is that the arm has come off of the shaft and/or has worn/stripped the rectangular fitting area of either the arm or the shaft or both. I believe that the screw can come loose leading to the stripping or detachment, but I also believe that the arm can strip the attachment point without a loose screw, but most likely the screw loosening is the precursor to the issue.
Now I never actually did any further diagnosis or work on this tractor after the end of the above video as I have 10 tractors and life happened. Hence no Part 2 video. But based on what I could see up in this very inaccessible and cramped area of the trans-axle and equally based on what can be seen in the manual exploded view I include in the video, I am fairly sure this is the problem.
There is a slight chance that a similar problem could occur on the other end of this little (approx 2-3 inch) shaft down inside the trans-axle, where a shovel-shaped end twists against a rectangular shim which actually lifts the hydro-static motor away from it's base to allow oil to bypass .. BUT I think it is far more likely that the problem is on the external end of the shaft. We have all seen arms/shafts with this kind of rectangular attachment point come loose. If you are lucky, then perhaps the screw simply came loose and things can be fixed by reattaching. Unfortunately I think any work on this bypass arm can only be done by removing the trans-axle from below. I suppose there is a chance that removing the seat and fender and fuel tank might allow sufficient access from the top, but the amount of work is probably the same done from below as from above and dropping the trans-axle is the only sure way. I'm guessing about access from above.
Dropping the trans-axle is much easier than it sounds. If care is taken with preserving the positioning of the shift linkages then this is very straightforward and shift linkages can be adjusted after the work. You might find that you can simply reattach the arm to the shaft and tighten the screw and add some Loctight to the threads to prevent loosening. If the rectangular attachment part is damaged (as it could be) then it might be possible to actually do a quick weld to secure the two parts. I would personally be fine with welding the attachment point to save me from a full trans-axle disassembly.
Worst-case scenario is if you replace the entire shaft and arm. It does appear from the manual that an nearly complete disassembly of the trans-axle may be required. Now the parts themselves are readily obtainable used from Ebay and complete with shipping you can probably get both the arm and the shaft for less than $30. I don't think you can get these parts new anymore but it might be worth looking.
I think a good step might be to just drop the trans-axle and see if the arm can be reattached easily, even if it needs a quick shot from a welder. If so then you are in luck. If not, then of course how much effort you might put in from there (which could be a lot) will depend on how much you love this tractor.
Good luck! - Maxhauler.
Small correction: It looks like rather than a screw, the arm is attached to the shaft using a c-clip. The best-case solution would be similar .. reattaching perhaps with a new c-clip, but more-likely, a shot from a welder, preferable to the full trans-axle disassembly. The c-clip usage lends itself to an increased likelihood that the rectangular area is stripped and also does not allow the use of something like Loctite to strongly secure a screw. Hit it with a welder if you can IMHO.
Apparently, TH-cam lost my very detailed response to you. It was like a full page long. In a nutshell, Look at the video at the 6:34 mark. The wire you activate from the rear of the tractor attaches to a spring that attaches to this two-inch long metal bar which attaches the vertical shaft coming out the top of the transaxle. A C-clip secures the bar to the shaft over a rectangular hole. My guess is that either the clip came off and/or the rectangular hole and matching rectangular part of the shaft are stripped. Parts are cheap and easily obtained (used) but replacing that shaft probably means an almost complete disassembly of the transaxle. I suggest removing the transaxle from below and WELDING the metal arm back to the shaft. I think this is the only reasonable solution, but that's just my opinion. I'm sure you just want to get it working again without too much trouble so that is what I suggest.
Well that's weird .. one day TH-cam has lost the big replies I wrote to you, then the next time I look they are back. Oh well. I guess they like to make me type a lot!
My bypass rod moves to open and close bypass valve but really needs a little force and it snaps in with pressure from my finger but ever since the last time I disengaged transmission it will not fully engage so my transmission is constantly in neutral. Any suggestions? You mentioned your issue was different as it seemed loose.
Hi Jill, I think the likely issue is this: the rod you push in and pull out connects to a 2 inch arm which is attached with a nut to the top of a vertical shaft. The nut comes loose and then the lever ca ride up off of it's rectangular post which fits the rectangular hole in the arm. Continued operation will very quickly destroy the rectangular hole and post. If you catch it early, the arm can be re-secured. However, it requires disassembly of a lot of the mower to have access. It might require taking off only the seat, fenders and an upper frame brace, or even a little more or even removal of the transaxle. It is a lot of work and for many people might not be an option, unless you know someone handy and affordable who. It is an achilles heel of otherwise great mowers. I'm not sure this is your issue but it is a common one, which this video shows. I wish you luck in resolving it. It is a good thing to keep our all American Craftsman tools going, because there will never be anything like that again. :) Take care.
you have to pull it hard and then the very last quarter turn is where it unlocks it
Not when it's broken like this one is. And really it is easy to brake if you pull it hard. If eveything is good with the tractor you should not have to pull it that hard, but these machines take a beating so I bet problems with this disengagement mechanism are common. I think the inside of the Hydro is pretty well built. The issue is where the lever attaches on top of the transaxle, as shown in the video.
@@maxhauler was your shifter in the middle between were your feet go at
I have a similar Craftsman and the disengagement lever does nothing. It's never worked.
Then you know how hard it is to move these when they are not running. If you cannot disengage one of these Hydro trans, you have no choice but to drag the beast around with locked up wheels. You have to run the engine and actually drive it even if you want to move it a short distance. Dragging it gets old really fast and is a good way to get a back injury. Such a small failure of this little lever can basically make a good tractor into junk. They shuold have made that lever attachment on the top of the transaxle much much stronger. I ended up pulling the good engine out, taking the new seat off and leaving the tractor out for the metal recyclers to pick up. It had some other issues too. Had to make room anyhow.
@@maxhauler PITA indeed. I rarely need to move it without running the engine. I do know that the brakes are seized also. It's actually the lever/actuator. I'm almost certain the lever for the hydrostatic disengagement is also seized. I'm hoping it's not an internal issue, but rather rust that has taken hold. Oh, and my wheels are seized to my axles as well, lol. Tried everything, the darn thing wouldn't budge. So clearly it was neglected before I took ownership.
@@JasonTylerRicci I pounded the fuck outa my rims to get the right side rim off then the whole half of the axle came off with the rim and tire then it was a little easier pounding that axle out of the damn rim what was holding it on so tight was the rusted up key i kept using old oil to try an help loosen it from the rim and it worked and it wasn't fun
Lots of details - but you can't hear a word of it.
sry about that.I usually get the audio/video right but I was out of practice for this video. if you turn the volume WAAAAY up, it is possible to hear. Just turn is back down again before the next video comes on!
Could not hear
turn your volume way up and you can hear but be sure to turn it back down before the next video comes up. I have some ideas on how to fix the audio but there is no great way to do it.
No idea what this video is about...couldnt hear anything!!
Yeah I know the volume is way too low. Now I know how to fix that for future videos but I don't know of an easy way to fix this one. If you turn up the volume all the way it is possible to hear. Just watch out when the next video comes up!
maxhauler thats ok...i just turned the volume up. Did you ever figure it out? I have the same problem on my husqvarna...it wont disengage to freewheel push. I guess its better than wont engage to drive.
my problem is most likely that the arm with the rectangular hole has stripped from the shaft that goes inside the transaxle to operate the bypass valve (if you can call it a valve as it's more of a wedge that lifts the motor cylinder up so oil .. bypasses under the base) .. OR there could be an internal problem. but the way it feels so loose I figure the problem is on the outside. in my video I pause for a second and show a green arrow where I think the problem is.
The one I just bought won't disengage, but it's also acting a little funny in drive.
I think I'm taking the rear end out like he suggested elsewhere.
I could hear you fine
Your audio is too low!
put a mic on! they're cheap
was talking about a thing called..bluetooth, ever here of it?, u can wireless clip mic on and will kill the ambient noise from your...cellphone?..is it? my rotary dial phone doesn't seem to connect to it, try it broham