Cub Cadet 1600 Drive Issue

sypherz28

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Lawn Wizards, every one of you! Thank you so much for the help thus far! I expedited two belts that are branded MTD yesterday. Comparing the pictures of them I can definitely see the 5L profile compared to what I purchased before. Hoping they arrive this evening.
 

bertsmobile1

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Took me a long time to get my head around belts,
I could not understand why there would be up to 7 different OEM belts for 7 different prices all supposedly exactly the same length & width.
That was untill I found the secret of the Gates catalogue cross reference
The gates equivalent of your front belt is in their Blade Runner series , 6606BR http://www.gatespowerpro.com/Comergent/en/US/adirect/gates?cmd=catSearchFrame&domProductQueryName=6606BR&returnURL=http://www.gatespowerpro.com/Comergent/en/US/adirect/gates&returnTarget=_top&gotoAdvSearch=false
Click on the gates belt name ( 6606BR ) and you will get a description of the belt in a new window.
The real length, effective length width and section
Note the belt is not really 5/8" wide.

I use this catalogue all the time in order to check if the belt my suppliers have said is OEM , really is OEM size.
Quite a few times, the effective length will be the same but the section will not and these are the ones that will work, sort of but not for as long as they should
 

sypherz28

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I received the new belts and realized they were identical to the ones I was taking off. I measured the belts with a micrometer and compared them to the Gates site and they match up. The belts are branded MTD with the proper part number. When I opened the rear end the dents on the shaft were in excellent shape, along with everything else I inspected. Teeth on the gears were clean and sharp. Bearing and bushings seemed factory quality. Could the PTO clutch have anything to do with it?
 

bertsmobile1

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no
Apart from being on the same shaft they have nothing to do with each other, unless the bolt that holds it on is loose
 

sypherz28

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It acts just like you describe with the belt issue, but they are branded properly and spec out accurately. I'm not the original owner so I'm wondering if there are other parts on there that are incorrect. Or there is definitely an issue with the rear end I couldn't identify.
 

sypherz28

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Okay so I am convinced this is still a belt issue but I am not sure what to do. The only thing I cannot measure is the cut angle of the belts but one is sharper than the other and Gates even shows its a 1 degree difference. I feel like If I had the same shallower angle as the the drive belt that it would resolve the issue but this is going against what the diagram says is the right belt. How would I go about finding a belt based on specs and not a part number?
 

bertsmobile1

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OK .
time to put on the deer stalker and get the magnifing glass out Shirlock
!) closely inspect the drive pulley for polished surface at the bottom of the V.
If it is polished it it worn beyond use and needs to be replaced.

2) get a long socket extension that you can fit into a power drill and a socket to fit on the nut on top of the big pulley under the battery.
What you are going to do is to drive the pulley via the nut and watch the tensioning pulley on the top belt.
If it pulls in tight, the mower lurches forward, it goes slack, then pulls in tight and the mower lurches forward then something in the transmission is working against the drive.
Generally it will be the brake so back off the nut in the middle of the brake and see if it runs better.

A tight brake will also make the mower difficult to push when in neutral.

3) last one is harder to do but you have to watch the tensioning arm on the front belt and in particular the spring.
If it ossillates when you are driving then the spring could need replacing.
Double check the pivot points for the front tensioning arm.
If the hole is flogged out oval then the tensioner can not apply sufficient tension to the front belt.

4) put some Bearing Blue on the centre shaft of the variable pulley.
jack the rear of the vehicle so the wheels are off the ground and run through all of the speed settings.
Then get under the mower and look for the blue on the inside of the belts.
If the blue has transferred to the belt then the sliding pulley is worn beyond its limit and one of the belts is running on the shaft and not the side of the pulley.

Some photos of the varaible pulley at each of the speed settings will also be helpful but please no hand held videos.
 

sypherz28

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I am just getting back to this thread and just now seen your last message. Going to try this very soon and ill report my findings.

Thank you so much for your help thus far, I owe you a brew or two!
 

bertsmobile1

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It is a 2 way street.
I work on about 60 mowers a year and of that about 45 are just routine services.
Thus the more odd ball problems that appear on here the more I learn.
Going back over the entire thread I am starting to wonder if the tension spring on the rear ( top ) belt is the culprit.
The entire system works by varying the load on that spring.
If it is soft, stretched or in the wrong place you get reduced drive because the front belt just pushes the sliding sheave fully up and runs on the center of the variable pulley and you set SFA drive when that happens.
 

sypherz28

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I can say that the top spring is extremely tight. It's almost a two person job putting that top belt on. I haven't looked at it yet but I do believe that lower tensioner is bouncing back an forth. I can feel it in the pedal. Hopefully ill be able to look at it today after work.
 
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