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Snapper Transmission problem

Discussion in 'Mechanic and Repair' started by rik, Jul 2, 2011.

  1. rik

    rik LawnSite Member
    Messages: 9

    I have an old rear engine Snapper rider. Model 25086S. While mowing along doing just fine, it will come to a sudden stop. It's like the transmission locks. If I go back and forth from a forward gear to reverse, it will eventually become unlocked and start moving along fine again. I may be able to go 15 minutes before it happens again or maybe only 2 minutes.

    While working fine, I have all the gears.

    Any ideas?
  2. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

    Worn chain and sprockets in the small transmission (one the drive disc mounts too) would be my guess, It's easier to remove/teardown and inspect than the fender gear case....
  3. rik

    rik LawnSite Member
    Messages: 9

    Is the a repair manual available anywhere? I'm pretty handy and have the tools but sure would like to know where to begin in taking it apart.
  4. Cleve

    Cleve LawnSite Senior Member
    Male, from Rockmart, GA
    Messages: 404

    I went through a couple of these mowers way back when. I think they will last forever if you take care of them. I just never liked the way they cut on turns.
    Anyway, you might check the rubber wheel that drives against the metal disc. Seems on one of mine I had multiple troubles with a bad batch of factory "rejects" where they would wear a spot on the rubber and acted just like you describe. Simple fix was to replace the rubber wheel.
    Note: I say I went through a couple of these because that was the first riding mower I ever purchased after getting married. My dad got one at the same time and I usually went over to his house and mowed his grass too.
  5. rik

    rik LawnSite Member
    Messages: 9

    I'm starting to really wonder now. If I stand it on end, the wheels spin - opposite directions - easily and the drive disk turns. Put it back down on the ground, in neutral, and the wheels are locked. The wheels absolutely won't turn forward or backwards.

    Made for lots of grunting and groaning getting it out of the backyard using a hand truck to raise the rear end. Those hand truck wheels were half buried.

    Does that still sound like a chain/gear problem in the chain case? Have no problem taking it apart, just don't know where to begin.
  6. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

    We sold Snappers for years before dump'n them.....

    Yes, It sounds like a chain case issue. This machine has what they call a smooth clutch, There's nothing in the disc that will cause the machine to lock up while mowing along.

    You likely couldn't get the machine to roll because the shifter wasn't in the roll position, This is the area between the park slot and 1st gear slot or the chain had locked up again.

    Do this, Set the machine up on the rear bumpers. Put a pry bar or long screwdriver in the slot on the yoke marked in red;


    Push down on the bar/driver and the drive disc will move away from the engine disc, Now spin both rear tires at the same time the same direction. Check for any binding/jumping or noise from the gear cases, When doing this the rubber disc should spin as well and everything should spin smoothly. Also note how far you have to move the tires before the disc starts to move.

    I don't have and couldn't find a service manual on your machine, But there's not much to them that I couldn't walk you through removal of the small trans if you like......
    Last edited: Jul 13, 2011
  7. rik

    rik LawnSite Member
    Messages: 9


    I did as you mentioned - pushing down on the yoke which is the same as pushing down on the brake? - and futzed around with several variations and could never get the wheels to both move in the same direction.

    The machine is in a no move condition right now. I'd always been able to get it to move by changing to different gears several times to get it unlocked but now it seems to be permanently stuck.

    So, taking apart the chain case seems to be in order. Can you give me the starting point? Looks like remove the left wheel, then inward. Correct? I have the exploded diagram in the Snapper Manual which will probably be a good guide

    Damn, I sure wish I could bring this thing inside to the A/C.....
  8. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

    Yeah, I'm sure it's a few degrees warmer 5 hrs south of me.....

    OK, I'm gonna give you a run down on how I do it.

    With the machine standing on the bumpers;

    1) Remove both wheels but only the right wheel hub.
    2) Loosen the two RH axle boot clamps then slide the boot off the fender bearing and small trans flanges.
    3) Remove the drive disc from the trans and set aside.
    4) Remove short shift linkage from the trans.
    5) Loosen the one clamp on the left boot and slide the boot off the small trans flange.
    6) Remove screw and nut #'s 35 and 31 along with the yoke bushing #34 (shown in above pic) and set aside.
    7) Remove all the screws holding the right fender to the frame and the cross rod between the fenders, Slide the right fender off then the axle boot.
    8) Only loosen the screws holding the left fender to the frame.

    Now comes the fun part, With all the above removed and loosened you will be able to lift up and outward on the RH axle shaft. At the same time push down on the yoke where the bushing was removed, Then slide the small trans out of the slot in the yoke and off the hex tube and axle shaft.

    Now it's just a matter of splitting the chain case for inspection, Remember...... These chain cases use 00 grease which any Snapper parts supplier should have.

    Good Luck
  9. rik

    rik LawnSite Member
    Messages: 9

    Well, got it all apart rather easily. Thanks for the step by step.

    Opened the chain case and, other than some old grease, it looks fine. All the gear teeth look great on both gears, the chain is intact and has no kinks. Everything spins just fine. There is nothing that shouts, "I'm the problem!".

    Any suggestions?
  10. rik

    rik LawnSite Member
    Messages: 9

    Looking closer, I see that the two nuts/bolts with the red arrows have been moving. There's fresh metal surface where they've shifted.

    That hub (left side as I'm looking at it standing on end, right side by the manual) doesn't want to turn very easily but it does turn.


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