LawnBoy S21ZSN Transmission Lubricant

Too lazy to reread everything. Did you change the belt?

Mower is new; belt is fine. There is no slippage on pully. I did run it a little with the cover off.

The mower was NOS when you got it....it had dried up grease that you removed.
If it where to use gear lube with or without limited slip additives, that is what the factory would have put in it.
I would suggest you drain the oil out...then flush it with diesel to get the residue out.....then put grease back in like it should have.
If you haven't damaged it....it should work.

jp1961 said:

I tried synthetic gear lube in the rear end of my Toyota Tundra (limited slip differential) and it acted WAY weird, making noises and slipping. Ended up replacing with conventional rear end fluid and the problem went away.

Snapper uses 00 grease in their transmissions available at Tractor Supply Company.

Jeff

Click to expand...

BlazNT said:

They make a limited slip additive that you must put in. If you don't it will destroy the rear end.

Click to expand...

Ok I want too straighten out this post. I was responding to the person with the Toyota Tundra "jp1961" That is why I quoted him in my response.

BlazNT: Now I understand. Sorry for the confusing followup question.

Unclelee: Taking it apart again this evening to clean it out again. I also took apart the wheel drive assemblies. The grease in them was more like wax. Should have figured it was more than just the transmission that needed re-greasing. Soaking in kerosene right now. I bought Sten "00" for the transmission. Is this also the right grease for the rear wheel axles and the wheel drive assemblies? If so, how do you inject it into zerk fittings when it doesn't come in a grease tube? (I'm talking about the zerk on the wheel and the zerk on the height adjuster.)

I use high temp grease that goes in one of these

Use type 00 or marine grease i torn down my single speed trans in my 10301 and pumped it full of marine grease and it works fine.

OK, just to close out the thread:

I took apart both drive gear assemblies (the ones that sit inside the wheels and drive them). The years had turned the factory grease to wax; the springs were not strong enough to push the key into the pinions. I scraped the wax out and cleaned them up with kerosene. Once they were completely clean I greased them with Stens 00 grease and reassembled. There doesn't seem to be a way to grease these assemblies other than to take them apart. I used a drill on the pully shaft (9/16" socket) to test the mechanisms, they seemed fine.

So it turned out this NOS S21ZSN had three different problems develop over the years of sitting at the dealership:

a) There was something in the drive cable at the handle end that stopped the cable return spring from disengaging the drive. I believe it was bug parts (blech!). With the help of silicon bicycle cable spray, I got little black pieces out of the top of the cable once I removed the bottom end so the cable could move its full stroke. Once the cable was cleaned up, it worked fine. Full, normal (i.e., when assembled) stroke of the actuating arm on a new S21ZSN is about 5/8".

b) The grease inside the drive transmission had turned to wax, making the transmission prone to not disengage when the handle is released. Even when the fork-shift was disengaged (by pulling the arm clockwise, toward the rear of the mower), the drive/driven plates kept gripping the driveshaft. Once released, they did not want to grip the driveshaft unless a lot of counter-clockwise force was applied to the arm - more than the spring-loaded arms could apply.

c) The grease inside the drive pinion assemblies had turned to wax (see above).

I tried the mower out Thursday and Saturday (about 3 hours) and am please to report the mower drives VERY well and has tons of power. Just like a new one, heh he. I am glad that I stuck with it and didn't remove the drive apparatus. It was worth the pain to get it working right.

Thanks again to all of you for your advice, especially Unclelee.

thanks for following up , good read

For what it's worth I went looking for 00 grease and the best deal for me was from amazon, a 9 oz. tube for a little over $10 ea.

In the search I called local Lawn Boy dealers and they said that that they now use white lithium grease. Being in a hurry to finish the job I went with the lithium grease.

In a short test everything worked well, but I'll reserve judgement until some time has passed.

If problem appear I'll try to remember to report back here.