Locking a differential on snapper mowers

[Montanalocal]

I was searching for a way to get both of the rear wheels to drive on my walk behind Snapper mower. They are notorious for having a fully open differential such that the wheel that has the least traction gets all the power, thus not having much traction on rough or steep sidehill spots.

I found a person who was locking final drives on riding mowers, and it gave me some ideas that I put into practice. Look at to get a general idea of what is involved.

Look at parts 1 and 2 to see the disassembly procedure.

I removed the transmission, split the case, and took the cover off one side of the bull gear assembly. What you want to do is to prevent the pinion or spider gears from turning, thus the axels on both sides are solid with respect to the bull gear and both axles turn and drive. The picture shows that I put several bolts and nuts inside the bull gear assembly, such that they jam the internal spider gears. It now has both wheels turning, and I can cut across steep sidehills without feeling like I am pushing it half the time.

 

[salecker]

You should have welded it...
The stuff you put in there will still allow a little movement and will start to chew up stuff.
The chewing up of stuff is going to produce tiny bits of metal that will start to migrate around in the oil finding bearings that need clean oil.Eventually these tiny bits of metal will take out an important part and you will have a repair with monetary consequences.

 

[Montanalocal]

Yes I agree with you, welding would be good, but I wanted to start with something that would be reversible if it did not work as planed. I sort of plan to do two things. One is to replace the loose fillings with two metal straps that will just precisely fit into the space between the bottom of the spider gears at the bottom of the biggest open space on both sides. These hopefully will not move or periodically come loose.

The other thing is that I am considering not filling the case with oil. The only moving part will be between the input gear and the bull gear, and these have quite large teeth, and probably will work for as long as I am alive with no constant lubrication. The seals on the shaft bearings are sealed bearings and probably will have a good long life at low speeds whether or not there is oil inside the case. We will see, and thanks for the feedback.