Export thread

I have a Yardman 13.5HP 38" cut. Model 13AC762F755. The transmission doesn't have power. It will move sometimes on flat level ground but when I get to a slope it slows down and stops. If I get off, it moves again and seems normal. The belts are not that old. I replaced the original belts and the new ones don't have many hours on them. I'm pretty sure they are routed right. They seem to be slipping. I used the part number MTD give me for the belts. Is there an adjustment I need to make? I always thought they were self tensioned. I noticed there is a copper colored bar down under there that has threads on the end with no nut on it. I don't know if that could be it or not.

First, the belt numbers you should have used as replacements are 954-04001A and 954-05040. Second, did you make sure that the variable speed pulley was moving freely up and down, before installing the new belts? Third, did you make sure the tensioner pulley, part number 62 on the attached diagram, is in good condition and the tensioner arm is moving freely. Any one of these or a combination will cause your problem. https://www.partstree.com/models/13ac762f755-yard-man-lawn-tractor-2007-walmart/drive-2/

I can't remember it was so long ago. I had Lowes order me the belts for it. Think it would be worth it just to change them again? When you say does the variable speed pulley move freely up and down I'm not sure what you mean.

Part number 63 on the diagram I attached. The center part of the pulley should slide up and down freely with no belts attached.

So you mean vertically straight up and down? It moves forward and backward when I depress the brake. I looked at all the pulleys and they are all moving when I engage the gears. I don't know what else it could be. It just loses momentum when I go up a slope. It don't even have to be a steep slope. Guess I'll try new belts then hope and pray that fixes it. I think I know what you mean now. I watched a you tube video some guy moving that thing up and down between the pulleys. I'll try that next chance I get. Thanks

Variable pulley #63 should move up and down when the engine is running only. Very difficult to see unless you can remove the seat. Please DON’T do that. The tensioner pulley #62 will move forward and backwards when you step on the pedal. What should happen is, as you step on the pedal the tensioner will tighten the drive belt, pushing the center variable pulley to go up. This will change the size of the top of the variable puller, increasing the speed of the variable belt.

I found out what the problem was. That nut holding the main pulley down came loose. I tried tightening it up and it ran better but still won't pull a slope. I'm thinking that hub mount is stripped and I need another one. Any idea how I replace that? Can I do it from the top or will I have to drop the tranny?

Have you tried resetting the position of the vari pulley? That usually needs to be done if you replace the belts, or the machine stalls while moving, runs out of gas. Put the machine on a flat level spot so it wont roll away. Then get on it start it up. Make sure your shifter is in neutral. Then put your speed control to the fastest speed and let the brake pedal out all the way. You may need to assist it with your foot to make sure it comes back all the way. I usually try that first if the belts dont look too bad. But what rivets said is all good too. If the vari pulley is full of crap or belt dust that could be it too.

Make sure that all of the bolts that attach the transmission to the frame are all there, if the ones in the front fall out then everything will flex the more load is on it, like going uphill. And the flexing may let the belts slip.

Should be able to do it from the top. Before getting parts, remove the pulley and pulley hub. Make sure the pulley hub splines are the only part bad. If the shaft splines are also sheared you will need to remove the trannie to replace the shaft.

skipper124 said:

I found out what the problem was. That nut holding the main pulley down came loose. I tried tightening it up and it ran better but still won't pull a slope. I'm thinking that hub mount is stripped and I need another one. Any idea how I replace that? Can I do it from the top or will I have to drop the tranny?

Click to expand...

Really depends on the mower setup. Some you can change without pulling the transaxle and others you have to pull the transaxle. Some have rod running across the pulley that makes impossible to remove the pulley on some models. Also the tension on the belt must be removed in order to do this.

For the pulley it has a star drive that may have been damaged and it mating hub may also have been damaged. We only a few hundredths of an inch thickness.

Yea I think I'm going to just drop the tranny so I can get a good look at it.. I need to get my impact wrench on that nut. I can't get it in there mounted up because a crossbar prevents me from getting a socket on it. I stuck a screwdriver in one of them pulley holes and turned it with a crescent wrench but I can't get much torque on it. After I do that I''ll remove the belts and check all the pullies to make sure they move freely. Thanks for the replies!

I don't understand why the thickness on them hub stars is so thin. They should be like the blade stars!

Not really due the pulley just don't see the stresses that deck does.

Transaxle input pulley nut is torque at 25-33 ft-lbs.

Well I tightened the pulley nut with the impact and reinstalled with a new upper belt. The old one was pretty worn out looking. The lower belt was in good shape so I didn't replace it. The variator moves freely up and down. I noticed the new belt looks just a tad bit bigger in diameter. I also noticed the variator assembly spring was easier to move into place than it was with the old belt. I didn't notice until after I had it installed the belt numbers were upside down. I don't know if that would make a difference. It won't move until it's in 5th gear then it takes off. While in the lower gears it will lerch a little but not move until it hits 5th gear. I used the part number for the upper belt given in an earlier post but I didn't get an MTD OEM belt. Any ideas?

Also does anyone know what size what main pulley nut is? I forgot to even look when I tightened it back up with my deep well impact.. I'm going to try and get a shorter socket to fit under that cross bar if I have to replace that belt.

FYI, when replacing belts on this style of transmission it is highly likely that you replace both belts at the same time.

skipper124 said:

Also does anyone know what size what main pulley nut is? I forgot to even look when I tightened it back up with my deep well impact.. I'm going to try and get a shorter socket to fit under that cross bar if I have to replace that belt.

Click to expand...

it should be 7/8" if they haven't changed.

I once had a Tractor Supply Husky mower that if I didn't use the factory brand drive belt, it wouldn't pull a hill at all. Cheap belts worked on deck, but tranny belt HAD to be factory belt.

AChrome said:

I once had a Tractor Supply Husky mower that if I didn't use the factory brand drive belt, it wouldn't pull a hill at all. Cheap belts worked on deck, but tranny belt HAD to be factory belt.

Click to expand...

Correct factory belts are necessary

I'm thinking that's it too. I should have got the factory right from the start. Lesson learned!

skipper124 said:

Well I tightened the pulley nut with the impact and reinstalled with a new upper belt. The old one was pretty worn out looking. The lower belt was in good shape so I didn't replace it. The variator moves freely up and down. I noticed the new belt looks just a tad bit bigger in diameter. I also noticed the variator assembly spring was easier to move into place than it was with the old belt. I didn't notice until after I had it installed the belt numbers were upside down. I don't know if that would make a difference. It won't move until it's in 5th gear then it takes off. While in the lower gears it will lerch a little but not move until it hits 5th gear. I used the part number for the upper belt given in an earlier post but I didn't get an MTD OEM belt. Any ideas?

Click to expand...

You are simply wasting your time if you don't put two brand new MTD brand belts on the machine!
I have seen too many instances where an old belt looked great but when a new belt was put with it and they were mismatched like that it had a bad chattering or roughness when you tried to smoothly engage the speed and it also had a very low top speed or they wouldn't pull hills.
I learned a long time ago not to try to cheat even if a belt looks good and NEVER use any other brand belts even when they say they will fit.
No one seems to be able to get the actual cut and the thickness just right because you'll notice they are not a traditional shaped v belt.

I can't remember if the bottom belt is factory or not. I got them from Lowes many years ago so they should have been. I ordered an exact fit MTD OEM top belt and will put it on and see what happens. If that don't work I'll go with the OEM bottom belt. Then if that still don't fix it I'm out of ideas.

skipper124 said:

I can't remember if the bottom belt is factory or not. I got them from Lowes many years ago so they should have been. I ordered an exact fit MTD OEM top belt and will put it on and see what happens. If that don't work I'll go with the OEM bottom belt. Then if that still don't fix it I'm out of ideas.

Click to expand...

If it has been that long then the belt is probably worn out too.

But as said before use only OEM belts on MTD CVT systems. Most aftermarket belts are "B" or 5/8 belts that simply don't work correctly. I even had companies trying sub a 1/2 belt or 7/16 belt on Cub Cadet riders. Again don't work.

I will do that. I learned a lot from this. Thanks for all the help.

Try resetting the vari pulley like i explained earlier it usually fixes that issue

Great news folks, hallelujah I think I got it fixed! I put the MTD OEM exact fit on the top and it will pull any hill in any gear now. So now that I got that fixed i noticed another problem crop up. The deck is making a funny noise and smoking. I noticed the stabilizer bar is not fully down in the slot on the deck. Once I get that fixed I hope it takes care of that problem.

skipper124 said:

Great news folks, hallelujah I think I got it fixed! I put the MTD OEM exact fit on the top and it will pull any hill in any gear now. So now that I got that fixed i noticed another problem crop up. The deck is making a funny noise and smoking. I noticed the stabilizer bar is not fully down in the slot on the deck. Once I get that fixed I hope it takes care of that problem.

Click to expand...

See, this is why I was so adamant and repeated myself many times and I tell everyone in this situation too ONLY USE GENUINE MTD BELTS AND ALWAYS REPLACE THEM BOTH AT THE SAME TIME!
My exact words are always that if you do not do this you are likely to have a chattery jerky pedal and or speed application and you won't get nearly the top speed you should and it probably won't pull hills.
You probably just lucked out by only having to replace the top belt because I think you just did the other belt more recently but even if a belt has been on for a week or two or anything over one or two Mo's I don't recommend leaving them on because when things aren't working properly it tends to wear that belt at a weird angle and stuff.

skipper124 said:

Great news folks, hallelujah I think I got it fixed! I put the MTD OEM exact fit on the top and it will pull any hill in any gear now. So now that I got that fixed i noticed another problem crop up. The deck is making a funny noise and smoking. I noticed the stabilizer bar is not fully down in the slot on the deck. Once I get that fixed I hope it takes care of that problem.

Click to expand...

On the deck problem, I'm not sure what you mean by the stabilizer bar being all the way down unless you're talking about the front one that it hangs from but it seems to me if it's smoking something is either missed routed on the belt or something has too much friction and doesn't want to turn.
The first thing I do is take the belt off or at least off of one pulley and then engage The blade cutting lever if it's lever activated and then make sure you can turn both blades spindles and all the other pulleys freely.
Sometimes a blade picks up a rock or a clump of dirt or something and wedges it between the deck and the blade and locks up and sometimes your bearings go on the pulleys etc.
Then make absolutely sure that the belt is routed properly otherwise it's going to smoke and wear out the belt even if things move freely enough.

I also noticed the belt guard was in the wrong hole. There are two holes close together on the frame and last time I took off the deck I must have put it back in the wrong hole (I had to chuckle after writing that) I looked at the parts diagram and stuck it in the hole it showed on the chart. That seemed to fix it.