Toro self-propel transmission rebuild questions

I have a Toro Recycler, Model 20016, Ser. #25000xxxx series. The transmission gears apparently stripped. I bought a replacement gear set (#104-8671) and a new bearing (#100-1048), but have a few questions about removing the old parts.

1. The bevel gear appears to be locked on the axle by what I suspect is a taper pin. Are there any tricks to removing and reinstalling this pin? I presume I can just tap it out with a punch and reinstall with light hammer taps?

2. I had ordered the bearing in case I found the bearing to be bad when I disassembled it. The old bearing seems to be OK--very smooth turning with no slop or grinding. Should I just reuse the old bearing--shouldn't these usually last the life of the mower? If not, how do I remove the old bearing? The pinion gear came out of the inner race easily, but the bearing did not come out with light hammer taps. It seems to be press-fit into the transmission housing. Do I just need to whack it harder? I don't want to damage the housing.

3. What's the best way to clean the old grease with metal debris out thoroughly? Some kind of solvent?

3. In looking at the new gears vs. the old, it's not entirely clear that the gears are stripped. Maybe they are just evenly worn to the point they slip, but I'm concerned there may be another underlying cause for the gears slipping. Could there be something worn that is allowing the gears to slide away from each other, like whatever positions the axle in place?

In hindsight, I should have forked out the extra bucks for the complete transmission on the axle, but now just want to make sure I don't bugger it up where I'll still have to spend more. Thanks for any tips!

Jim

 

I would guess the gear is held on with a roll pin which would be driven out and back in.

If the bearing isn't bad and doesn't want to come out, I'd leave it.

Wipe out the old grease that you can, then wash out the rest with carb cleaner if you must.

Without seeing and inspecting it, I can't give much of a guess why it's slipping. Are the gears actually worn? Can they pull away from the pinion to allow them to slip? Has grease leaked from anywhere? If so, this would be a good indicator of where the problem might lie (worn bushings allow grease to leak by).

 

On the one I had apart the seal covering the underside of the bearing came out and let dust in the gearbox, as the dust and grease accumulated in the gear teeth the pinion gear rode up on the ring gear and started to slip eventually creating total failure, however the stress from the process had made the bearing to pinion gear shaft very sloppy, I felt it wouldn't last long without replacing the bearing, my solution was to remove the pinion gear all together and make it a push mower. Have a good one. Geo

 

Thanks for the response, Cheese. It could be a roll pin--maybe the hole is filled with dust that made it appear to me to be solid.

Yeah, think I'll leave the old bearing there until I have a further problem. I'd be concerned with being able to get the new one seated correctly to hold the pinion shaft straight. I'll just have a spare bearing on hand.

geogrubb, the replacement gears came with a new gasket for the housing, which I thought was odd because there was no gasket when I took it apart. I bought a "refurbished" mower, and I wonder if it was the transmission that was refurbed and reassembled without the gasket, which probably did lead to dust getting inside increasing the wear of the gears. But since this mower was designed to be self-propelled, there wasn't much emphasis on reduced weight--it weighs way too much to be a good push mower, at least for the size of my yard!

Thanks for the help, guys!

 

To see how much slop is between the pinion and side gears, assemble it and pull the axles away from the gearbox, then check the up/down play in the input shaft. The slop can be corrected by shimming the gear(s) with shim thrust washers if needed.

 

You didn't find the gasket/seal because it was ground up by the ring and pinion gears, when it fell it was on a loop between the ring and pinion and had no where to go, if you look closely you will find bits and pieces in the gearbox residue. Have a good one. Geo