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I just bought a '96 STX38 with 5 speed gear tranny from a lady down the road from me for $150 last week. She had said it was occasionally having problems going forward at times, so I mowed with it for a few minutes and didn't have any problem so I bought it anyway figuring for $150 I'd take a chance. Well I mowed with it today and after about 10 minutes, sure enough it lost power and finally got where it would barely creep forward. Now logically in my mind I'm thinking it's the drive belt that may be worn out where it's tight enough to run the tranny when cold but when it heats up it loosens and won't drive the tranny anymore. Does that make sense to those perhaps more in the know that me? I looked at it and it's not frayed or anything but it looks pretty old and dried out.
 

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Discussion Starter #2
Update:

Okay it's a few hours later and it still isn't moving. Should the drive belt always be engaged even when the tranny is in neutral?
 

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Update:

Okay it's a few hours later and it still isn't moving. Should the drive belt always be engaged even when the tranny is in neutral?
I had one of them tractors years ago and not for very long. From what I remember the belt will go slack when you push in the clutch/brake.

Also make sure that the pulley on top of the transmission is turning the shaft.

Another problem that tractor had was being worked on by idiots. Had to fix like 50 things to get it running and driving. Never did get the deck back on before I decided to sell it.
 

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Well, it has slack all the time right now. I don't know if a tensioner or something is amiss. Either way I'm still happy with the purchase. The deck has new spindles, pulleys and blades, the engine runs great and the steering is tight. I'll probably just store it until spring. I have a pretty good lawn equipment guy who still only charges $40/hr labor for repair work. Even if I have to put a couple hundred into it to get it right, it'll be worth it to me. May just need a belt and some adjustments.
 

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The belt could've been changed at one time with a non deere belt.I would replace it with the proper belt and be sure to route it properly,check JD parts they show it.Also check the idler pulleys that their good.
While the belt is off grab and spin the trans pulley it should make it creep forward or reverse depending the rotation.There looks to be a key way on the shaft if that is stripped could be part of the problem also.
 

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Well, it has slack all the time right now. I don't know if a tensioner or something is amiss. Either way I'm still happy with the purchase. The deck has new spindles, pulleys and blades, the engine runs great and the steering is tight. I'll probably just store it until spring. I have a pretty good lawn equipment guy who still only charges $40/hr labor for repair work. Even if I have to put a couple hundred into it to get it right, it'll be worth it to me. May just need a belt and some adjustments.
Is your tractor gear or hydro drive? I'm sure this will make a difference.
Is your PTO switch a yellow button that you pull up to engage or a metal toggle switch?
The gear transmission should have the metal switch and also have 2 pedals. One on either side of the hood. The one I had was gear. So the clutch pedal definitely slacked the drive belt when you pushed it down. A spring applied tension to the belt when you release the pedal.

I'm not so sure on the hydro drive.
 

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Is your tractor gear or hydro drive? I'm sure this will make a difference.
Is your PTO switch a yellow button that you pull up to engage or a metal toggle switch?
The gear transmission should have the metal switch and also have 2 pedals. One on either side of the hood. The one I had was gear. So the clutch pedal definitely slacked the drive belt when you pushed it down. A spring applied tension to the belt when you release the pedal.

I'm not so sure on the hydro drive.
As mentioned in the original post it is geared. It has the yellow button and a single pedal on the right side. Not like what you're describing at all.
 

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As mentioned in the original post it is geared. It has the yellow button and a single pedal on the right side. Not like what you're describing at all.
I see that now. lol
Not sure of the year that I had. Looked at some on Tractor House to refresh my memory. Looks like this model had quite a few changes over the years.
This is what I'm 100% sure on.
It had a metal toggle switch for the PTO on the right rear fender. Along with the transmission shifter.
Pushing down the pedal definitely slacked the drive belt to stop the tractor. Letting up on the pedal makes the belt tight and away you go.
 

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Don't know if this will be of any help because it's been a while since I replaced a belt on my STX46. The picture below is for a black deck model. If you have an earlier model with a yellow deck, there are some differences, but the drive belt setup is similar, just more parts I think.

The spring has to be unhooked before anything is loosened. You may have to loosen or remove the idler up front. Loosen the belt guide parts up front. Any of the parts that can be loosened and not totally removed make reassembly much easier if you only have two hands or old and non flexible like me. I believe the clutch can be left on but the wire would need to be disconnected to clear the belt. The steering rods will need to be disconnected also IIRC.

The tensioner arm, guides and idler get removed. Make sure the arm (22) and bushing (23) are not worn out. The belt may be removed from the rear pulley without removing or loosening the belt guides, maybe not.

Check the bearings in all the idlers and "V" pulleys. If rough or noisy, this is the time to replace them. I think there is a slight adjustment at the idler/ tensioner #11, as a slotted hole where the carriage bolt locates in the frame. It is probably more to get the tensioner located so the belt can't rub itself or the belt guides, than adding tension to a worn belt.

The worst part for me is replacing the deck. Not the friendliest Deere design here. A 4' 2x4 under the rear of the deck helps for wiggling and aligning to the lift attachment.

STX46 traction drive belt M74747.jpg

tommyhawk
 

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The belt could've been changed at one time with a non deere belt.I would replace it with the proper belt.
Beg pardon but what makes a JD belt better than a non-JD belt? I've always bought third party belts on all my mowers without problem. I don't buy the cheapest ones, I always buy premium kevlar belts. As long as the specifications in terms of length and width are correct, what difference other than price makes a JD belt better? This is an honest question.
 

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Thanks for the diagram, tommyhawk. I finally had time to get under it and take a good look at things. I noticed the spring from the tensioner was missing except for a little piece of the hook. So I went back to where it quit moving in my yard and sure enough, there was the rusty old spring lying on the ground. Strangely, it didn't make much difference in the feel of the clutch pedal. Bought a replacement for $4.50 and all is well, though the belt to the tranny does look pretty worn. I'll replace that next spring. Thanks for all replies.
 

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If you can get a belt from another supplier that does indeed match the JD specs., there would be no difference. JD and others use different angles on the "V" , lengths that are not in even inches, sometimes the width is a bit different that standard belts. They and others do this on purpose because they would like to have your replacement parts money. I do believe JD and some others try to provide belts to their own specs. (even when they don't manufacture them) to make the equipment keep working as designed.

Why are they going up in price each year? Dunno! Can after market belts work just as well? Yes, in many cases they will. One place I personally would not use anything but the JD belt is on the older GT's that have a variable speed drive system. Another is any place that function is critical and the dad-gum belt is really hard to change. In some places the different angle and slightly longer or shorter belt you might try will be just fine. Other times it is just wasted effort. A lot depends on whether the equipment has adjustments to get and maintain proper tension.

When the JD belt for the STX46 got to $70, that made me willing to try something else. It was time consuming to replace and a lot of effort and a few choice words to get it on to the clutch pulley (too short?). I put on a "red letter" belt that was $20 including tax. It was 1/2" longer than the OEM spec. Width was good, angle unknown. I was willing to waste $20 on my own equipment to find out. Works fine and lasted 4 seasons. JD belts in this case were only lasting 2 seasons.
So, I might be out of line with my reasoning, but that's my opinion. If something else works as well and costs a lot less I stick with it.

p.s. Glad you found the spring as the problem. Wish I had thought to mention that possibility.

tommyhawk
 

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Beg pardon but what makes a JD belt better than a non-JD belt? I've always bought third party belts on all my mowers without problem. I don't buy the cheapest ones, I always buy premium kevlar belts. As long as the specifications in terms of length and width are correct, what difference other than price makes a JD belt better? This is an honest question.
JD in their wisdom have made their pulleys at a different angle than standard belts.Though you may find the right length and width the angle of the belt will be different.The belt ends up wearing and slips by the time it works in the grove.
 

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Beg pardon but what makes a JD belt better than a non-JD belt?
They fit! lol

I have always had good service from JD belts.

My 1999 JS61 self propelled walk behind mower. Only ever replaced the drive belt once. Just looked at it today while scraping the deck. It's still good to go. A helper was using it when the first one broke. She chopped it up good before shutting down the engine.

My 2005 L108 tractor. One drive belt and 2 mower deck belts.

My 2014 X540 tractor. Still running the originals.
 

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JD in their wisdom have made their pulleys at a different angle than standard belts.Though you may find the right length and width the angle of the belt will be different.The belt ends up wearing and slips by the time it works in the grove.
Yeah, in their wisdom for their own $bottom $line. There are also after-market pulleys with standard angles to be bought. If necessary I would rather replace the JD pulleys with those to avoid paying over-inflated prices for JD belts every couple of years. I hate when companies pull that crap of slightly deviating from standard specs on parts for no other purpose than to gouge the prices on their own brand.
 

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Yeah, in their wisdom for their own $bottom $line. There are also after-market pulleys with standard angles to be bought. If necessary I would rather replace the JD pulleys with those to avoid paying over-inflated prices for JD belts every couple of years. I hate when companies pull that crap of slightly deviating from standard specs on parts for no other purpose than to gouge the prices on their own brand.
Not to defend JD but any belt drive has to supply the proper amount of traction to drive the load properly. Sometimes some slipping is good and sometimes not so much.
The only part of a V belt that should touch the pulleys is the sides. If the belt touches the bottom or sticks out above the pulley you are going to have problems.
 

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I'm with you H-D dealer dude. I don't mean to bash Deere either. My dealer is just 2 miles from home and I get a lot of items there that go on something else because in the end it costs less than running all over the country to find it. lol

Some don't remember before the internet, home computers, and smart phones. Where did you go to even inquire about a belt for an International built Cub Cadet, Dynamark, Craftsman, or Wizard to name a few? At least 30 miles for me. And more than one trip. Prices for those belts used to seem much higher than similar belts for my Deere at that time. When any of them go NLA, and Deere is no exception there, (except they are still in business) one must find something else that works even if it means changing pulleys etc. to get it back in use.

And good point about the friction surfaces and shock load requirement for a particular application. Something I did notice on the variable speed drive belts on on the 110 thru 200 series tractors were substitutions in belt numbers. The newer belts were not as thick as the older ones. Seem to work just as well but they were replacing 30-40 year old belts (restorations) that looked bad but still worked as they should. I was guessing that JD made these substitutions to avoid the problem of the thicker original designed belt bottoming out in well worn sheaves. Or maybe just a cost savings. :unknown:

tommyhawk
 

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diagrams are backwards from what you see from under the mower.

I assumed that those diagrams were what I would see from under the mower looking up, but, NO.
They are made looking down from the sky, so my mind had to work kinda backwards, like in a mirror.
Please don't do what i did.
 
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