Toro mower self-propel not working
#1
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Toro mower self-propel not working
I have a Toro Recycler Model 20016, S/N 2501xxxxx. The self-propel capability has slowly died out over a few weeks to where it no longer even turns the wheels, let alone pull the mower. I first readjusted the tension on the actuating cable with no effect. I then replaced the belt, but noticed the old belt wasn't stretched out at all compared to the new belt. But the belt still seems very loose. I assume it is supposed to be loose on the pulley until you pull the actuating cable, which should push the drive pulley outward to tighten the belt, right? But the belt remains too loose to grab the pulley. What gives?

#2
Have you checked that the pulley is actually turning the transmission, I had one where the transmission had never been lubbed and the gears were stripped, there is a seal at the top of the trans that comes loose and lets the gears not mesh well and they slowly get destroyed. Have a good one. Geo
#3
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Thanks for that tip. In checking that out, I found that the lock nut holding the pulley was loose, allowing the pulley to spin independent of the gear. I had trouble tightening it again because I had no way to hold the stud the nut turns on. I engaged the gear to hold the shaft so I could turn the nut and got it tight, so that tells me the gears are meshing and not stripped.
Now, when I engage the drive, the belt does turn the pulley, and if I raise the front wheels they will rotate. But they won't rotate against the ground and the pulley stops rotating. It still seems like the belt is too loose, and it's just slipping against the motor shaft pulley, even with the new belt. See the below picture...there's this much slack with the drive engaged...I can almost pull the belt off over the pulley. This can't be right, but I confirmed the belt is the correct belt: Toro Part #91-2258.
Any thoughts on how a new belt could be loose, or is there something else I'm missing?
Now, when I engage the drive, the belt does turn the pulley, and if I raise the front wheels they will rotate. But they won't rotate against the ground and the pulley stops rotating. It still seems like the belt is too loose, and it's just slipping against the motor shaft pulley, even with the new belt. See the below picture...there's this much slack with the drive engaged...I can almost pull the belt off over the pulley. This can't be right, but I confirmed the belt is the correct belt: Toro Part #91-2258.
Any thoughts on how a new belt could be loose, or is there something else I'm missing?

#5
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Cheese, I can't say how much tension is in the spring, but it is enough to pitch the pulley as far forward as it can go. You can't see it in the picture, but the support that the pulley is on is in hard contact with the mower deck...can't move anymore forward to tighten the belt. I'm baffled. I suppose I could grind out part of the deck to allow the pulley to move out further, but there must be something else wrong that a brand new belt is still too loose. Any other ideas for troubleshooting?
#6
Is this the correct belt number, an original, not aftermarket? I'd say your belt is a bit too long.
#7
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I'm sure the part number I ordered is correct--Toro OEM V-belt #91-2258--for my Model 20016, S/N 2501xxxxx. The bag the part came in is labeled with that part number. I've emailed the company I ordered the belt from to see if they have an explanation.
Otherwise, is there anything inside the transmission that could account for the pulley not pulling the belt tight enough? I just rebuilt this transmission 2 years ago with new gears, but don't remember much about how its assembly works.
Otherwise, is there anything inside the transmission that could account for the pulley not pulling the belt tight enough? I just rebuilt this transmission 2 years ago with new gears, but don't remember much about how its assembly works.
#9
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Geo, with the engine off, if I engage the drive and pull the mower backward, the pulley rotates indicating the gears are meshing with the wheels driving the pulley. And with the engine running and the drive engaged, if I raise the front wheels, they will turn, but not once they are back on the ground, like it just can't carry much torque at all. Could the gear alignment change under load to where they no longer mesh?
#10
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I have the same exact mower. It came with a blown engine. Someone tied the govener wide open and blew the rod in many pieces.
I will look at mine and let you know something. It does not have a belt and I have to take the plastic guard off to see the area you have posted !
I will look at mine and let you know something. It does not have a belt and I have to take the plastic guard off to see the area you have posted !
#11
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Thanks for any other thoughts you can come up with. I'm stumped. I hate to take the next step and buy a new transmission when everything is pointing to a loose belt, even though it's a brand new OEM belt.
#12
Take the bottom off the tranny, 4 screws as I remember, see if everything looks like it should, no flop or slop, then throw up your hands. The engine don't move, the front axle don't move, it either is the belt or the transmission pulley. Have a good one. Geo
#14
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I emailed the place I got the belt from about the apparent looseness of the new belt, and they said the pulley on the "blade drive assembly", which is what drives the belt on the motor shaft, could be worn, causing the belt to be loose. One reviewer who bought this part mentioned that the diameter of his pulley had decreased a quarter inch from wear. That would also explain the gradual loss of drive torque I've noticed. I have ordered that part, so I'll report back about how that works. Fingers crossed...
#15
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Eureka!!! The new blade drive fixed it! Of course, nothing's ever easy...the thrust washer inside of the old drive that you have to reuse in the new one did not fit in the new one. I had to grind down the OD to make it fit even with an OEM part. For the next guy's benefit that has similar symptoms, below is a picture of the old and new drives, side by side. It's not real obvious, but you can see that the nice straight taper on the new drive pulley is more of curve shape due to wear on the old one, which relaxed the belt tension gradually. Not what the reviewer I mentioned above had said about the decrease in diameter...my belt hadn't even been contacting the straight diameter of the drive pulley.
Thanks to everyone for the input on this...I hope this helps the next guy.
Thanks to everyone for the input on this...I hope this helps the next guy.

#16
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Jim where did you get it, how much, and the part # please.
I need the source so when I get a engine for mine I know what to get. The blown motor that was halfway on mine wasn't the motor that came with it !!
I need the source so when I get a engine for mine I know what to get. The blown motor that was halfway on mine wasn't the motor that came with it !!
#17
Glad you got it figured out. It wasn't what I would have expected to begin with. I'm not sure I've seen one worn badly enough to cause the belt to be loose before now.
#18
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It's Toro part number 106-3987. Here's the link to Mower Partsman via Amazon for the part:
Amazon.com : Genuine OEM Replacement part For Toro Lawn mower # 106-3987 BLADE DRIVER ASM : Lawn Mower Deck Parts : Patio, Lawn & Garden.
Amazon.com : Genuine OEM Replacement part For Toro Lawn mower # 106-3987 BLADE DRIVER ASM : Lawn Mower Deck Parts : Patio, Lawn & Garden.
#20
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I got it from Mower Partsman Amazon store. Their price was $17.69 I think. I had bought the new belt from them, and they suggested I try the blade driver when I emailed them about the new belt still being too loose, so I just used the link they provided.
I didn't really think that pulley could be the problem, but I guess it makes sense with all the debris flying around under the deck that must act as an abrasive to the pulley over billions of revolutions.
I didn't really think that pulley could be the problem, but I guess it makes sense with all the debris flying around under the deck that must act as an abrasive to the pulley over billions of revolutions.
#22
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Toro Mower Self propell not working.
Having worked for a Toro Distributor for 35 years, your problem got my interest after you had it fixed, but I see that you have mentioned OEM part numbers and parts purchased from Amazon etc. The only time my customers had problems with New Toro Parts not fitting on old Toro Mowers was when an aftermarket part with the "will fit" designation was there before, or trying to fix a problem now. If you have Toro Brand Items and buy your parts from Toro Distributors, a lot of problems like the one above go away.
#23
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Yes, I'm leery of "will fit" after market parts too. Although I purchased them through Amazon, I made sure they were actual OEM parts, and the order was fulfilled by a mower parts distributor via Amazon.
That said, the fix only worked for less than two hours total operating time! It worked like a champ and took off like a bat out of hell the first time I used it after putting the new blade driver. But the next time I used it, the drive started fading again after about 20 minutes. I did notice it was making a different noise than it ever had before. It sounded like the gears were making the noise...kind of a whine. I wondered if finally having the correct belt tension has made another issue become apparent.
I removed the bottom cover from the transmission. The grease appeared to be plentiful and reasonably clean. I could only see the main gear that is attached to the wheel axle, and its teeth seemed to be in good condition. But I noticed the axle could be moved back and forth about 1/8 inch relative to the gear box. Since the axle gear is also moving with the axle, I think this would change the amount of gear mesh with the pinion gear on the drive pulley axis. Could there be other worn parts affecting the axle gear position within the gear box, allowing the axle to move where it shouldn't be able to, to the point that the teeth were barely meshing and rapidly wore down? Are there some parts that properly position the axle/gear that could have worn, and might be worth replacing before biting the bullet and getting a whole new transmission?
That said, the fix only worked for less than two hours total operating time! It worked like a champ and took off like a bat out of hell the first time I used it after putting the new blade driver. But the next time I used it, the drive started fading again after about 20 minutes. I did notice it was making a different noise than it ever had before. It sounded like the gears were making the noise...kind of a whine. I wondered if finally having the correct belt tension has made another issue become apparent.
I removed the bottom cover from the transmission. The grease appeared to be plentiful and reasonably clean. I could only see the main gear that is attached to the wheel axle, and its teeth seemed to be in good condition. But I noticed the axle could be moved back and forth about 1/8 inch relative to the gear box. Since the axle gear is also moving with the axle, I think this would change the amount of gear mesh with the pinion gear on the drive pulley axis. Could there be other worn parts affecting the axle gear position within the gear box, allowing the axle to move where it shouldn't be able to, to the point that the teeth were barely meshing and rapidly wore down? Are there some parts that properly position the axle/gear that could have worn, and might be worth replacing before biting the bullet and getting a whole new transmission?
#24
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Toro Self Propel not working
All of your concerns are viable, but if you have the gearbox back together, a quick test will tell you if you have a gear box problem. Raise up the mower so the drive wheels can spin when the drive is engaged. If the axle shafts both spin even when you but a little drag on the wheels with your foot, the gear box is probably ok. If the axles spin but the wheels don't you could have a problem where the gears that drive the wheels are not meshing due to wear in the gears, the axles, and the wheel bushings. (Very common) Good luck!