The model is 13AS679G062........... SERIAL NO. 1E297B40081. I erred when I stated deck/drive belt. It was the drive belt that was half-split and was replaced when I had it torn down for paint and maintenance over the winter. The deck belt seemed fine so it was not changed.

Double checked the mower just now and you are correct. There are TWO drive belts. I had the machined almost completely disassembled over the winter so if the second drive belt showed any wear or fraying I would have ordered it also. I honestly don't remember now if I had changed both drive belts. Would a stretched drive belt(the second one) produce the problem? The motor RPMS do not fall off at all.

***"Would a stretched drive belt(the second one) produce the problem?"***
Sure will, a little wear to the variator pulley assembly can mess things up too (item # 82 in IPL).
The so called "transmission" in this tractor is really nothing more than a gearbox that permits the operator to select forward or reverse (plus the differential gears). The actual different speed ranges are determined by the different diameters of the driving pulley (crankshaft belt, aka primary belt) and the driven pulley (variator belt). As you change "speed ranges", the diameter of each pulley changes to affect the new speed position. When you select "granny low", the primary belt pulley becomes smaller in diameter while the variator belt pulley becomes a large diameter. If you select "head for the barn high speed", the primary belt pulley becomes larger and the variator pulley becomes smaller. It is recommended that the two belts of the vari-drive speed system be replaced only as a set (both belts) to assure that both belts will orient in their respective pulley grooves correctly. Any wear in either belt can affect how much power can be transmitted through the belt and pulley system at a given ground speed. That means when both belts, and the variator drive pulley assembly, are new and snug, they should be able to transmit max engine torque at the highest ratio afforded by the system. But, when you have worn belts and/or pulleys, you will need to find a lower ratio to transmit the same torque, and that means it can only be done at a slower ground speed. The other consequence of having any slippage in this vari-drive system is that because of the dusty, gritty environs of operation, any slipping of a belt wears the surfaces where the belt is supposed to get a good grip, making it even more likely to slip. I'm going to guess this tractor has 500 or more hours on its clock. You would be justified in replacing item # 82, variable pulley, as well as item # 79, second belt at this time. I believe a "one year old belt" will live OK with a new variator belt. I'd be reluctant to trust the variable pulley at 12 YOA, so do them both while you are that involved.

Here is a link that might be useful: MTD family vari-drive

I have the same type, make sure the rear belt tensioner moves easy, and that the spring is on it, or a spring that is on the vari drive pulley is there, been awhile and cant remember just where the spring is. but if its gone or loose, you wont move either

Good points johninmd, It's been a couple of years since I changed the belts on my MIL's Troy Bilt. It uses the same vari-drive set up.
bilbo, if you don't have the MTD Owners Manual for your tractor, you can get one online at MTD by plugging in the Model number. Thats how I got the manual for my MIL's Troy Bilt. The cost is nice: $0, and you might even be able to get a discount.

thanks a million guys.... got quite an education and will order the second belt and pulley right off....hopefully I wont need any more advice in the near future,but I will try to let you know how everything worked out....thanks again!

Interested in your advice on replacing the VS pulley Mownie. Have you found some to be a problem even if they work freely?

***"Have you found some to be a problem even if they work freely?"***
tomplum, my suggestion to change this variable pulley in this case is more subjective than objective in that bilbob states he routinely used his tractor pulling heavier than recommended loads, uphill too. Because of the heavy loading of the variator pulley under those conditions, I have a good reason to infer that the movable parts of the sheave may have worn a bit more than they would have under less strenuous loading. I realize there are no pre-determined limits on the life of various components, but since bilbob noted that his problem began during the time he was using his tractor for some serious haulin', probably best to replace that key component in the belt system. The most overlooked or forgotten factor in V-belt drives (of any type or application) is the width and depth of the pulley belt grooves. The ability for a V-belt to get a good grip on the pulley requires that only the sides of the belt and the sides of the pulley V-groove be in contact. The pulley belt grooves must be deep enough that the narrow, flat apex (the Vee) of the belt does not come in contact with the bottom of the pulley groove. This is rather simple for the pulley makers and the belt makers to address in the design of rigid pulleys, you just build your pulley with deep enough groove that the belt would have to be nearly worn away on the sides before it could ever bottom in the pulley.
But, in a vari-drive V-belt system, it is a bit more challenging to design and build a system with a variable geometry pulley, that will maintain all the desired angles and depths at CONSTANT standards that V-belt drives need. Even a bit of "tilt" in the moving sheave will affect how the belts fit in their respective grooves. The suggestion to R&R the variator pulley in this case is to make certain any problems or wear are not continued.
Regarding the aspect of "working freely", there may be a "fine line difference" between working freely, and being worn to looseness. I don't know if there are any wear limits to gauge one of these pulleys against. The only other thing I might add to this is the bearing in this pulley is sealed, and as such, is "lubed for life". Question here is: "How long does this bearing live?" Those are my reasons and opinions. :^)

Interestingly enough, you've probably noticed a design change in recent years to which the bearings are serviceable. Had one of those too that the bearings died (seized actually) but they are common bearings and easily replaceable. I'll pull the older style and take liquid wrench and spray the sleeve work it back and forth to get the gunk out so it works free and to clean it up well when I do belts. A little fresh grease on the bearings and back on it goes. If I'm not replacing the belts, for better or worse- I pop the clip and spay in some moly chain lube that hopefully keeps those bearings happy. Just curious what someone else may do.

Once again, I thank you guys for an ongoing education (tuition free to boot) on the working of my main lawn tractor. I will be taking Mownie's advice as to changing the pulley while I'm at it since 12 years of cutting 5- plus acres in addition to other yard jobs has surely put 500 or more hours on the machine. It has been a relatively trouble free machine over those years and the motor seems as strong as ever. Therefore I am inclined to replace the pulley with the supposition that there are many more years of service available to me in this tractor with some common sense maintenance. I really was not aware of the logistics of how my power train operated until you guys opened my eyes. Muchas Gracias

Here's to another 12 years!

I want to openly thank Mownie for his expert advice. Just replaced the second drive belt and v.pulley and am happy to report all systems go. The hill that my tractor would not pull in 5th speed now not only climbs it with ease but will also climb in 6th and even 7th speeds. Replacing the v.pulley was a bit of an expense (approx 100.00) but I feel that it was well worth it to probably add another decade of useful life to a tractor that was relatively cheap to buy new (I paid about 1200.00 for it in 1997). Anyone with the same problem can feel confident that Mownie's advice will solve the problem. Great forum here. I will scan it from time to time for sure. Thanks again to all for their help.

Well, you're welcome, but I wish to add that this is a "collective forum" with input from lots of members. Various members have either once worked in the field of OPE, or still do on a daily basis. Other members work in related occupations (or once did) and collectively, this makes up a pretty good foundation at which to throw problems. I want to thank other members for remaining interested and active in making this forum such an interesting place to hang out. I'm not the last word for problems (though I might be the "wordiest" poster. My hat is off to all the other folks that contribute to this process. SALUTE!

Forgot to add that the annual cost for replacing vari-drive pulley worked out to around $8.33 per year. Not too bad.

I have a troy bilt mower manufactured in 2006 that is having the same problem since I overworked it with heavy cart loads. I also bag wet grass often since there is no time to wait for grass to dry. I have some nasty hills I go up and down and I am loosing power usually running in 2nd gear. It has slowly gotten worse over time and slips to the point of sliding me forward in my seat when going downhill. It has also left me stranded half way up the hill with a lot of weight of grass behind me, not to mention myself. I found moving the clutch back and forth tends to make the downhill trip more smooth without the jostle. I thought the gear box was the issue but after article here I think I may have solved it with the belt and pulley issues you all have spoken of. I have the same 3 belt system so I am going to try all the good advice I found. Just wanted to say thanks to everyone for taking the time to write. I would estimate 1,000 hours on my machine. I use it for commercial use mowing multiple yards each week. 2010 will be my 4th season with the mower. A few minor things have needed replaced and "tweeked" but overall has been a great mower. Thanks again and I will report back once the repairs are made and tested. One more thing. Does anyone know the "what, when, why and where" for deck wheels for my troy bilt? Model #13AN77TG766. Serial# 1F066B40324.
Thanks in advance.

machine made by MTD... link to parts manual:

http://manuals.mtdproducts.com/mtd/GetFile.do?filename=769-01612b.pdf

Pp 18,20,22 - depending on size of mower deck you have....

get the wheel p/n -should be able to get from MTD or try a google search...

Here is a link that might be useful: parts manual for troy-bilt

Trumpet-
Using the machine as you do, I would replace both belts, the rear idler and possibly the bearings in the VS pulley. If the VS rolls smooth w/o the belts, the bearings could be fine- but make sure the center works freely as well. On some that slip long enough on the front drive pulley, it is best to scuff the burnish so it grips better.

Gentlemen,

I have the same slip problem you've described but I have another symptom. When I'm in hi gear and can depress the clutch and stop the slip --- but about half way down the pedal travel, something pops then it goes again.

suggestions?

Many thanks

The Raptor

Hey Guys,

I have the EXACT same problem. Mostly in 5th, going up slight inclines which I've done for 4 years with no problem. I have 2 of these, one's done it from day one (used) the other is now starting to do it (newer).

I have replaced both drive belts, took apart the V-speed pulley (cleaned with carb spray, light sanded) It moves up and down freely. I use it sometimes without the F/N/R cover to see WHY only in 5th?? 4th is too slow for most yards I do, and 6th and 7th is too fast to cut in. I can "cheat" and push the pedal in a little, or all the way, to get up the hill, but it doesn't run in 5th even on level ground.

I'm stumped. Any input would be very helpful!! This isn't something I'm going to drop off at a mower shop and HOPE they don't take me to the cleaners just to get my machine back.

My direct email is m_a_bachman@yahoo.com

Always make sure the the engine pulley is not glazed when replacing belts. It is common on hill climbers. And for the 107th time- use only OEM MTD belts.

tomplum, When you say glazed, do you mean slick/ wet?

Slick, yes- where the old belt slipping has made the surface that way and not able to grab the side of the belt. The side of the belt is what should be driven. Scuffing them with emery cloth /sand paper make a world of difference. Wet, btw is never good. Sometimes you can find a drive pulley that has been so fatigued that the pulley needs replacement.

Thanks tomplum,

I sanded the front drive pulley with a drill sander with rough sand paper. Put it back together, works fine now.

I actually have two of these mowers, almost identical, different year.. It worked on one, but not the other?? these belts are new, also, from MTD.

...any other possible ideas??

"I actually have two of these mowers, almost identical, different year.. It worked on one, but not the other??"
I should have mentioned that this only works on odd numbered production years..... oops!
Is your VS pulley where you can see it when operating- with the cover off perchance? Older versions you could at least hope to see the belt action. Or- after trying to climb a hill- which belt is warmer? Is the rear belt warm at all?

Gentlemen, I have a 'troy bilt' mtd mower that is doing the same thing, I used it for 2 years in a lawn care business after I bought it new in 2007 with very little trouble but now that I am only mowing my own yard I guess wear and tear finally caught up with it. I replaced that almost impossible to get to belt under the seat area and in the past have replaced at least one, maybe both of the other drive belts. The mower also needs some deck work, I think it needs a spindle, so if the VS pulley runs 100$ and I need to replace the other two belts also (I seem to recall they weren't too cheap) I am beginning to wonder if it may be too much trouble to bother with.

It is best to price things out first. Now, variable speed pulleys don't typically need replacing. If they have been allowed to rust badly, show wear on the pulley surfaces, or feel as though they have wear in how the center moves on the stem - it would need replacement. Older models did not have servicable bearings and if they failed, replacement was the suggested repair. If one is patient, they can be pulled, rust buffed off and soaked in penetrant and then see what you have. Obviously, oil on new belts isn't good, so they have to drain fully and be recleaned. Newer models, should they have a bearing failure will have a dual ball bearing which is replacable. Sometimes spindle bearings are replacable w/o buying the assy- which saves good $$ on MTD's.

THE REASON SOME UNITS WON'T PULL IN CERTAIN SPEEDS IS BECAUSE THE VARI-DRIVE CENTER PLATE IS STICKING. 5TH IS THE MOST PREVALENT PROBLEM SPEED BUT ON SOME TRACTORS 4TH AND 6TH ALSO GIVE PROBLEMS.
.
THIS SOMETIMES HELPS.
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Remove the deck.
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Remove the FNR shift knob and cover plate
. ..
Put shift lever in 7TH speed
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Put FNR shift lever in neutral
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Start tractor and push clutch all the way forward
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Shut off tractor while holding clutch forward
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The variator will be fully open and the belt will be at the bottom of the pulley
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Spray the pulley center between the belt (drown) with WD 40 Don't worry it wont hurt the belt.
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Start the tractor in neutral and work the clutch in and out a dozen times.
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This time leave the clutch out and shut off the engine.
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The other belt will be at the bottom of the variator
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Repeat the spray process on this half.
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Go thru this procedure 3 times it should remove any sticky ness and it should not hang any more.
If this doesn't work replace the Variator. About a hundred bucks.
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If you have to change belts its much easier to clean the center of the variator when it's off.
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Do not use grease to lubricate the variator center plate it gets sticky and causes the plate to hang.
. .
Be sure to sand the motor pulley.
.
Rodd Diehl
.
Old Houseboater

My fellow MTD Brothers we love our Variator Transmissions. They're a marvel of simplicity. I wish I could know how many of them were made, and how many might still be out there running. But they all have one thing in common: They tend to eat belts. They will all need new belts eventually.

So everyone's homework assignment tonight, is to memorize these numbers: 954-0280A (front belt) and 954-0730 (rear belt). Last time I looked, the pair of them are about $50 at most places. Even though other belts might fit, they won't last as long, so use only the MTD belts. Depending on how hard you work the tractor, you should expect to get about 100 hours out of the belts. Stock up on them. The rear belt goes through more bending than the front, so it usually starts cracking first. Fortunately it's the easier of the two to replace. I got the process down to about 45 minutes, back when I was mowing commercial with this tractor.

The Variable Speed Pulley has a hard life too. It spins at engine speed, and takes the torque loads of the drive train. And it runs hot. Lube its bearings once a year with high temp wheel bearing grease.

And the engine pulley, over enough years will wear out too. If you can see a grove down in the "V", where the belt has worn it down, start looking for a new pulley. You can de-glaze it and that would help for a while, but replacement is the better fix once the pulley starts getting grooved.

Here's to keeping alive our weapons of grass destruction :O)

About replacing the drive belts on the MTD Varispeed drive train, some time ago I wrote up a procedure for doing this, oriented to the home mechanic. This procedure is for the MTD-600 chassis, which includes the nearly world-famous Wards Signature 2000, and many others. If it says 'Varispeed', '7-Speed Transaxle', or 'Shift-On-The-Fly", that's all based on the MTD-600.

The document includes a couple of small associated diagrams, which I'm not sure how to post here. Assuming there would be interest in this, I was planning to post a link to the procedure. However, the GardenWeb system informed me that posting links to another site is forbidden here, so as to prevent advertisements, etc. This wouldn't have been an advertisement, just trying to share some information.

I guess if there's interest, one could send me a private message.

The only fool proof way to eleminate not pulling in 4,5,6 speeds is to remove the variator pulley and clean it. Over time varnish builds up on the surfaces of the center bearing and causes the center section to hang.

Materials Reuired: Carb cleaner, Kroil or similar.

Remove pulley - spray carb cleaner on shaft and
move center disk up and down. keep repeatng spraying and moving disk until brown residue stops showing up on shaft surface. This takes several applications of cleaner. Don't stop too soon, you can't over do it.

After it's clean give it a shot of Kroil or euivalant.

I had this same issue on my lawn mower. I replaced the upper drive belt and it started working like a charm. I made a video while I replaced the belt. You can see it here. https://youtu.be/G20J6LrHgM8

I have a problem with the variable speed pulley. I have cleaned / lubricated the centre shaft with WD40 so that the centre plate moves up and down and rotates freely without the belts on. When I put the belts back on and drive, the centre plate sticks at the top of the shaft so that only the highest speeds work. Is the VSP worn out and needs replacing? Your thoughts please.

I have an MTD 600 series from 1998. Bought used 5 years ago and have not had many issues with the belts or going up and down hills till now. I replaced both belts at the beginning of the season and now even after making the adjustments to the speed control rod(6 speeds) then adjusting the speed control link while engine is off and in 2nd gear it will move fine for the first 10 feet or so then as it starts to go up hill it slowly comes to a stop. If I change gears it will start to move up the hill for a foot or two then stop. Next gear same thing, I have adjusted both links close to 100 times trying to follow the instructions but I just can't seem to get passed 2nd gear (once I got it, I mowed the lawn). Now it wont go up hills again. As for the VSP based on advise above I pulled it partially off and put 80w-90 gear lubricant in the center hole. I rode without the center cover on in and the pulley seems to work perfectly in terms of opening and closing based upon the speed selected (speed 6 high tension, speed 1 low tension etc). When going up the hill the VSP stops spinning completely, push the brake clutch in releases the tension on the belts then let it go and it spins again but quickly comes to a stop with tension. I have a video if it will help. But at this point short of replacing the VSP and I'm not sure that will correct it I'm not sure what to try. Any suggestions would be appreciated.

If the VSP seems to be working and it quits spinning there isn't enough belt tension. Correct OEM belt a must. The drive pulley can certainly be cracked, glazed,key spun, oil on the belt etc.

Thanks for the suggestion, I'll continue trying to adjust the tension to get it correct.

I have an MTD Pony (13AN779G766) but I am sure all similar drives can have this problem. Mine started slipping at the crank pulley after about 15 minutes of usage. I'd have to get off to limp it out of my ditch. I assumed DRIVEBELT and replaced it. The problem persisted and nothing changed. So, I replaced the secondary belt (variator to transaxle input) and still no change. I bought a new engine main drive pulley and although there was some wear on my old one - it was apparent the belt was bottoming out because the shaft was shiny. Still after 2 belts and a new pulley - it still slipped after getting hot. It was slipping at the crank because I put my GoPro under there to record what was going on. Now to the variator. This is a simplistic and genius device but after dropping the spring on the idler pulley and putting the machine in park/brake and removing the battery I was able to lift both belts free from the variator. It was slightly loose and noisy in the bearings and the variator center pulley slid up and down but did with some effort. One single bolt removed from the bottom of the variator shaft will allow it to lift straight up from its bearings (don't lose the spacer that goes on top of bearings). They're housed in a triangular bearing fixture that is bolted to the variable speed gear selector and simply come out from the bottom. I replaced both bearings which are available anywhere if you search part #6203 or take them to an auto parts store, they are a common part. You'll need two. I cleaned the variator inside and out with Brakleen and after drying gave a little shot of machine oil on the shaft. Put it back together and made absolutely sure the three pulleys are all the same height - my idler was bent upward about 1/4". I ran the hell out of it today and it never threatened to slip and even pulled hills from a dead stop in high gear. If I knew then what I know now, this would have cost me 10 bucks and a couple hours work. On the flipside, I addressed all pivot points, bearings, blades, and maintenance items in the process. Here's to another decade!

I have a 455 Deere mower. It has oil in the radiator and antifreeze in the rear end. I'm sure the radiator is leaking into the oil cooler lines and needs the radiator replaced. I found one from a 455 but it was a 2 wheel steer, mine is aws. Will it work?

I have a 455 Deere mower. It has oil in the radiator and antifreeze in the rear end. I'm sure the radiator is leaking into the oil cooler lines and needs the radiator replaced. I found one from a 455 but it was a 2 wheel steer, mine is aws. Will it work?

I have a very similar problem as bilbob430 with my Yardman mower. It has a 13hp Briggs and stratton engine. In one of your responses you asked if he lost RPM's, but I did not see where that issue came up. I am having that problem, I lose power when blades are engaged or I am in gear. I get the same speed in gear 5 that I do in gear 1. Engine idles fine but bogs down when blades are engaged or machine is put into gear. Compression is good. I put in new filters and new belts.

if you park machine on flat surface, bring engine rpm to rabbit and then engage deck blades, does engine bog down/die then?

So, this is the front pulley on the shaft of the motor. I have replaced both drive belts, I've even put a 1" shorter belt on the front for it to try and get more grip. The tractor moves again, but only on flat ground and barely. I assume I am either going to have to replace this pulley or take it back off and scuff it up way more than I did when I put it back on.

It seems there should be more polished area on the pulley. Has this pulley been changed at some time in the past with a pulley that is too wide?

This would make the correct belt seem to large.

Not that I"m aware of, the mower was manufactured in 2002. It's a Huskee brand mower, I think it has 24hp motor with a 46" deck, but I'd have to double check. As others have stated earlier in this thread, when running it in low range, it seems to pull way better, but trying high range it struggles.

I was given a lawn tractor, with the Vari-drive. Spent countless hours rebuilding that infernal machine! Had it running, repainted it, cleaned engine, etc. Looked really nice. Rolled it out! Looked at machine, saw smoke rising from hood area, then flames! EGAD!! I pushed it away from garage, shouted: "Burn, baby--Burn"

Never another Vari-drive! Rusty Jones

What if i get a mower with varidrive and put a geared transaxle in it

Got a brand new 36 inch deck lawn king MTD ride on

lovely machine but only used it 6 times now pulley belt looks stretched by at least 4 inches . Cutting to lowest setting but weekly, cut once when grass was damp. Am I doing everything wrong. Previous old ride on just went on forever

Changed the drive belts on my Huskee (MTD) 4200 tractor and worked fine for a few minutes then experienced the same loss of power issue. Pulled he battery and rocked the tractor and felt it bogging down, even in neutral. Wiggled the brake rod and the problem cleared. Pulled the right rear wheel and found that the brake lever was binding and not fully disengaging. A shot of WD-40 freed the lever (be sure to cover the brake disk) and cured the problem.

I have a 2006 Huskee LT4200 you've heard so much about belt slippage. I'm going to change belts and adjust varispeed. How do you adjust varispeed?

/

lt4200

My experience with this MTD variable speed drive is that the drives don't slip until the belts are real bad or you have a loose mount. It is best to replace both belts at once, but as the rear belt wears much more quickly, you typically can just change that belt. If the front belt is noticeably worn or is chunking, then it gets replaced obviously. If the front belt gets replaced, for sure do the rear or you may have a low speed issue. You absolutely have to use the OEM belts. The linkage was set up properly when it was new and should not typically need adjustment unless it has been fiddled with or damage occurred. The adjustment is an adjustable end like a tie rod where you pull the pin, unlock the jam nut to make the adjustment. Look for binding linkages and that the transaxle mounts front and rear are secure. The VS pulley should both turn freely and the center sheave should move up and down freely as well.