# MTD Riding mower Trans



## RKDOC

I just got in a Yard Machine riding lawn mower. Model #13AC66F123 Serial #1D153B40114. The mower will move in 5th - 6th - Reverse, but will not move in 1st - 2nd - 3rd - 4th. I have never been into the transmission on a mower. I have looked at the parts breakdown, but not sure I could spot anything that wuld cause this problem. Any suggestion what to look for before I tear into the transmission. Thanks greatly for any and all suggestions.


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## glenjudy

What's the make and model of transaxle ?
Couldn't find mod/ser on MTD or other sites.
The shift keys are usually the first suspect, but, if they're good enuf to engage 5, 6, R , should engage others unless the shifter gears are worn for the others.


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## 30yearTech

Double check the model number as I was unable to find a parts breakdown on this model number. 

Most MTD products have a variable speed drive set up and if it works in forward and reverse in any of the speeds then the problem is not in the transmission. If it's a tractor style remove the battery and battery box and this will give you access to the vari drive pulley. This is a split pulley that changes is diameter when the center part slides up and down, resulting in different drive ratio's. Sometimes the center part of this pulley will sieze up and not "float" as it's supposed to this will limit the drive. There is also a tension spring on an idler pulley that maintains tension on the short belt that drives the differential, if this spring comes off or breaks then the top belt will loose tension and the drive belt will slip. The condition of the drive belts will also affect the operation of this type of variable speed drive set up.


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## RKDOC

Sorry for the misinformation (need to learn to type) The model # is 13AC662F129 (this is the mower model #) Where do I find the transaxle model numbers?

Thanks for the help.


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## glenjudy

Will be on transaxle, I would follow 30year's advice before I'd suspect transaxle.
It's probably a one speed, F & R, two at most if you have hi and lo feature.
The model nos. are usually 11 chars long, would it be this ?? 13AC662F129 (2003)


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## 30yearTech

Well thats the closest model I could find when I was looking. This is a vari drive unit, so if it will move in forward and reverse, the transmission should be alright.
Check the drive belts, pulleys and idler arm springs and see what that looks like.


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## tommyj3

I agree with 30year on this. If you need belts use only MTD replacement belts. The vari-speed drive is very finicky went comes to belts.


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## RKDOC

I did as was suggested and checked all the belts, springs,linkage and found no problems. Suddenly I realized I had broken the first rule of trouble shooting, OPERATE THE MOWER MYSELF. Works fine for me in all speed ranges.

Now for a little education. The lever that changes gears doesn't seem to move anything. It has a cable attached that locks the park brake when engaged. Then has a rod that is hooked to the clutch pedel rod, but just free floats at the end of the range selector lever. I can see no linkage to the variable speed pulley. What accuates the variable speed pulley to change speeds?

Some insight to how the speed is varied would be greatly appreciated. Thanks for all the time and help everyone gives.


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## 30yearTech

The speed selector lever limits the clutch travel, if you set it to a slow speed and operate the unit you will notice that the clutch pedal releases very little. Now move the speed selector to the highest speed and you will see that the clutch now comes much further out. By allowing the clutch to come out more the idler pulley puts more tension on the drive belt, this in turn forces the split pulley to ride up more, decreasing the size of the driven pulley and increasing the size of the drive pulley which increases the drive speed on the transmission pulley. It's kind of like the torque converter drive of a mini-bike or go-kart.

Hope this explanation helps some....:thumbsup:


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## RKDOC

Thanks 30 Year. That helps a lot. With that explanation is it possible that the variable pulley is not expanding as it should at times, thus causing it to not give speed variations? Or could the belt be worn (even though it looks good) enough that when warmed up the belt does't fit the variable pulley tight enough to work properly?

Thanks for the help!!!


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## 30yearTech

A worn belt could case some sliping, I have also seen the pulleys wear as well. It's also possible that one or both of the belts may have been replaced with an incorrect type belt. MTD belt usually have the belt number imprinted in the back side of the belt, you might want to check and see if you can find the numbers on the two drive belts and check them against what belongs on the mower just to be sure.


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## RKDOC

Thanks for the reply's. On the split pulley should I be able to move the split pulley to make sure it is moving up and down when the tension is applied and released? Could the split pulley be binding sometimes? Thanks for the help.


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## 30yearTech

Yes, you should be able to move the center of the split pulley by hand. You will have to remove at least one of the belts to check the pulley, as it can be hard to move with the belts installed and tension on them.


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## TerryC

I have an old tecumseh HS50 engine i'm tryin to get running. But i keep having probs with the cARB. it Leaks real bad. I have soaked it in parts cleaner and rebuilt it and it still leaks. Can anyone give me some pointers as to what the prob is?


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## glenjudy

Would be better if you would start a new thread with your problem. Specify both model and spec of your engine with problem description.
hope this helps,
thanks,


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## RKDOC

The variable speed pulley was bad. Replaced it now it runs great. Thanks for all the help.:


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## JoelMcElrath

I've read this thread about the variable speed pulley and decided to see if I could detemine why my MTD transaxle is slipping. It only slips on slow speeds (1, 2, maybe 3), but is okay on 4-7. It is a model# 13BN771G729. The short belt looks pretty used up and after mowing awhile, the smell of burned rubber is pretty evident. I want to change the belt, but can't get it off the transaxle pulley because it is too close to the frame. How do you get the belt off/on?


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## 30yearTech

I can't recall ever coming across one that did not have enough clearance between the frame and pulley to get the belt off. You could take the pulley loose from the input shaft to the transmission by removing the retaining nut, then lift the pulley up off of the input shaft. That should provide more then enough room to remove the belt. The retaining nut is accessible if you remove the battery and holder.


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## JoelMcElrath

Thanks for the response. Perhaps, I should look again with better light. I'm suspicious of the variable pulley getting a bit cranky because sometimes it works fine in speeds 1-3 other times it doesn't move.


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## RKDOC

If you lie under the mower, there is a bolt in the center of the variable drive pulley. Remove the bolt and you can take the variable pulley off. There are belt guides around the pulley, that is why you can't get the belts off without removing the pulley.

Best of luck!! (it's realy quite easy)


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## hobe

*leaks*

sounds like your float has a hole in it and is full of gas and not shutting off the fuel.
hobe


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## tjean

*mtd riding mower*

I have a mtd rider that will not go into any gear. I rebuilt the trans and put in two new 42-tooth Bevel Gear,Clutch Collar,Detent Shaft Assembly. They were wore bad. Everything else looked good. But i have one question on the Differential Assembly does it slip when the drive shaft engages with it. It seems to move the axel but i can stop it with my hand.

Please help me 
Thanks
Tom


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## painter775

*pully*



30yearTech said:


> Double check the model number as I was unable to find a parts breakdown on this model number.
> 
> Most MTD products have a variable speed drive set up and if it works in forward and reverse in any of the speeds then the problem is not in the transmission. If it's a tractor style remove the battery and battery box and this will give you access to the vari drive pulley. This is a split pulley that changes is diameter when the center part slides up and down, resulting in different drive ratio's. Sometimes the center part of this pulley will sieze up and not "float" as it's supposed to this will limit the drive. There is also a tension spring on an idler pulley that maintains tension on the short belt that drives the differential, if this spring comes off or breaks then the top belt will loose tension and the drive belt will slip. The condition of the drive belts will also affect the operation of this type of variable speed drive set up.


ii also have a problem my mtd 13aq695h120 gets slower and slower the longer that u run it,cant find the var.pully that you talked about,tood them off but there all look to be fixed


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## 30yearTech

painter775 said:


> ii also have a problem my mtd 13aq695h120 gets slower and slower the longer that u run it,cant find the var.pully that you talked about,tood them off but there all look to be fixed


Your unit does not have a vari drive pulley, it has a hydrostatic transmission. Low fluid level or old fluid may be causing your problem. The transmission does not show any service parts available for it


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## painter775

*thanks*

thank you very much,man u r fast.going to check it now.


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## mawermaniac

*mtd tranny problem too*

I just got an mtd yard machines model #13ax675g089, tranny #618-013B. Iwas told the oly thing it needed was a coil. I replaced the coil engine runs fine but the mower wont pull in either direction. I looked under the mower to see if a belt was broke, no broke belt and the main pully on the tranny was spinning but mower wasn't moving. Any ideas?


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## 30yearTech

mawermaniac said:


> I just got an mtd yard machines model #13ax675g089, tranny #618-013B. Iwas told the oly thing it needed was a coil. I replaced the coil engine runs fine but the mower wont pull in either direction. I looked under the mower to see if a belt was broke, no broke belt and the main pully on the tranny was spinning but mower wasn't moving. Any ideas?


check the key's on the axle for each wheel and make sure they are not missing or sheared. If one key is missing, the mower will never move.


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## saulman1

*White LT 13 Lawn mower*

I have a White LT13 mower with a clutch/brake problem. When clutch is engaged, the pedal vibrates. It stops when disengaged. Is this just a belt problem or a more serious problem


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