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Walker PTO gearbox

Discussion in 'Mechanic and Repair' started by ericg, Sep 9, 2007.

  1. ericg

    ericg LawnSite Silver Member
    Posts: 2,797

    I have six Walker 42" Model "T" mowers and they have all suffered the same fate ealrly in their working life. The plate that the PTO gearbox (for the blade driveshaft and the grass impeller) is bolted to cracks causing one or more of the bolts holding the gearbox to the plate to shear. This in turn causes the box to exhibit excessive vibration. More often than not, when the box is removed, the boss for the screw that holds it down is broken, making the box unuseable. Yesterday, this same thing happened again to a mower that is two years old. This time, as before the boss on the box was broken but I decided to swap the top and bottom halves of the PTO box and filled in the small hole with metal epoxy. Sine the boxes are in the $275.00 range, this seemed like a good idea. After repairing the crack in the plate that holds the pto box and reinforcing it from the bottom, we have never had a repeat problem. Has anyone utilizing Walker mowers ever run across this problem?
  2. AAELI

    AAELI LawnSite Senior Member
    Posts: 362

    Have had problems with excessive vibration developing from pto shafts that were not greased regularly which caused higher than normal pressure on the box and mount. This in turn contributed to the sequence you describe.

    I have ordered just the box halves themselves and replaced them in an effort to keep the cost down.

    Were the units under warranty? Did you let your dealer know of the problem? Have you gotten any help in getting the problem resolved? The reason I ask is that Walker has been very good at looking over problems in an effort to address and solve the problems.
    Al Eli
  3. ericg

    ericg LawnSite Silver Member
    Posts: 2,797

    One of the units were under warranty and the PTO box was replaced and the crack welded. At this point, I am just resigned to repairing the rpoblem myself. The problem is that the dealer did nothing to reinforce the plate that the box sits on. Walker has been responsive but the frames on the machines need to be upgraded. In fact, the newer Walkers have beefier side rails after many people complained about side rail fractures which I have experienced as well. The fix for that problem is to just weld plates on either side of the fracture. I have an Exmark Navigator in addition to the Walkers. The frame on that machine is built like a tank but the driveline is not as robust as Walker. If someone could build a machine that utilizes the Navigator frame and the Walker running gear, it would be a home run. Now that I realize that the top and bottom halves of the Superior PTO box is interchangeable, I will just swap them from now on. The driveshaft and associated u-joints are tight with little or no play.
  4. mojob

    mojob LawnSite Senior Member
    Posts: 515

    Are the operators lowering the engine rpm before engaging the blades?
  5. ed2hess

    ed2hess LawnSite Fanatic
    Posts: 13,190

    I got a 2000 year Walker and 36" deck.....the entire 3 gear box assembly for the blades seem to be attached to the deck by two bolts on each end by the spindles. I don't see any bolts or support in the middle where the drive shaft gear box is located....is that different on 42" units?
  6. gene gls

    gene gls LawnSite Gold Member
    Posts: 3,213

    I had a bearing failure at about 3200 hours. I had the gear box rebuilt. Nothing was mentioned about the box its self as having any cracks.
  7. ericg

    ericg LawnSite Silver Member
    Posts: 2,797

    Ed2Hess, the box that I am referring to is mounted on the frame right behind the right side wheel. It is this box that operates the grass handling system as well as the driveshaft that comes out to the mower deck.
  8. fixer67

    fixer67 LawnSite Silver Member
    Posts: 2,100

    Check to see if the PTO shaft is hitting the front of the mower. If the deck is tilted up like going up a steep hit while the deck is engaged the PTO shaft will hit the front of the machine and cause it to bend. This then causes excessive vibration and the will damaged the PTO gear box. I have replaced many PTO gear boxes but have not see the mounting plate weld break. I have seen the bolt come loose and damage the gear box. Just worked on one today as a matter of fact. The most common cause of excessive vibration that I have seen is due to a ware or bent PTO drive shaft.
  9. ericg

    ericg LawnSite Silver Member
    Posts: 2,797

    Fixer, the shaft is not hitting the mower as most of our properties are flat. It is not the weld that is cracking but the plate itself. The crack usually starts in the middle of the plate closest to the right side tire and gravitates to the front hole closest to the left side of the mower. As I stated in a previous post, after we reinforce the plate from underneath, we have not experienced any further issues. Many of our machines have over four thousand hours with Kohler 20 and 25hp engines and the same PTO box once the modification waqs made.
  10. fixer67

    fixer67 LawnSite Silver Member
    Posts: 2,100

    4000 hours is a lot of hours!!!
    I have seen Walkers come in the shop with 2000 or more but not 4000 yet. Never seen one of those plates crack. If I can remember I will ask the Walker rep about it the next time he is in the shop. How old are those machines? Model and serial would be nice.

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