Export thread

First time on and sharing an install of front and rear Height Adjuster arms.

Toro Model 20043, SR-21S, 6.5 HP, direct drive (20 years old?).

For the longest time my height adjustors were falling out of place and finally realized the rivet holding it in place on all fours was starting to fall out and scraping against the aluminum height notches. Scraping the aluminum notches can severely damage the ability to hold in the height adjustor.

Ordered two front and two rears (oem) and had to order some miscellaneous parts since they wore out (wheel bolts severely worn in front). I have had this mower from day one and never checked this stuff otherwise maintained well. I at least, using a grease gun, greased the rear pivot arms through its life.

My suggestion is to always have a schematic, clean out before taking off, and put the parts back in the exact same way.


The fronts were not difficult, but rears took a long time due to number of parts and some parts worn.

May replace more parts since tire bolts new but inside of tire where old axle bolt was worn had some play after install of new bolt in front. Rear has just a little play.

The pivot arm may need to be replaced also since there is some play in it in the front.

Testing this weekend.

Also lubed everything with white lithium grease.

Schematics and detailed manual on Toro site.

Any comments appreciated.

Please don’t lube the drive components, will just attract dirt and. Cause rapid wear. This manual may help you out. https://www.toro.com/getpub/22446

I understand that and you are correct. I thought about this alot because of that. The grease fitting nipple requires NLG2 white grease so must do that and it also states to grease all transmission parts. However, I clean my mower with water after every run.

My mower is weird also it states Model 20043 with SR-21S, but Toro site is Model 20043 with 21SB. I used Model 20042 with SR-21S for schematic since it included o ring.

Product Information - Used to find information​

• Model #: 20042
• Serial #: 200000001 - 200999999 CHANGE
• Product Type: Walk Behind Mowers

Wheel pinion clutch - I am pretty sure this is mine.

From manual


1. Check the innermost groove on the output shaft which is located 2-1/4” (5.7cm) in from the end of the shaft; make sure that the O-ring seal is present and intact. This seal is important to keep grease in and contaminants out. Replace it (Item 6) if necessary (Fig. 170). Some models do not have this O-ring. Mine fell apart,

2. To increase service life, make sure all parts are clean prior to assembly and coated with new grease.

Testing today so will see,

Thank for your feedback but still bothers me greasing the parts.

there is a long standing argument on the forum whether to follow factory greasing specs or not. The last mower I worked on was dry, no grease left, and every part in the drive wheel clutches were destroyed from the moisture that got to it. The mower with grease was worn but the parts were in better shape. Both mowers are used on the same grass (ajacently maintained yards identical mowing habits), same frequency and are the same age mowers, The real solution in my opinion is to use the correct grease but service the parts annually to keep them clean. Most people won't pay that expense in time or money to have someone else do it. That said, it is on my to-do agenda annually now.

I understand that and you are correct but the

sgkent said:

there is a long standing argument on the forum whether to follow factory greasing specs or not. The last mower I worked on was dry, no grease left, and every part in the drive wheel clutches were destroyed from the moisture that got to it. The mower with grease was worn but the parts were in better shape. Both mowers are used on the same grass (ajacently maintained yards identical mowing habits), same frequency and are the same age mowers, The real solution in my opinion is to use the correct grease but service the parts annually to keep them clean. Most people won't pay that expense in time or money to have someone else do it. That said, it is on my to-do agenda annually now.

Click to expand...

Your point is well taken "The real solution in my opinion is to use the correct grease but service the parts annually to keep them clean" Thank you. On my agenda too now. Maintenance can be costly besides finding a reliable person, and I try not to have to buy another mower since a good one is expensive.

If you flush enough grease into said parts then you are also pushing out the sand and grit the grease attracts.

Really don’t understand that post. Been working on the Toro drive systems since the early 70’s and have found that dry lube, if you use anything, is better than grease. I’ve always told my customers best is go dry and service annually.

If I see a zerk fitting it's getting some grease. Right or wrong t'was put on there for a reason.

Rivets said:

Really don’t understand that post. Been working on the Toro drive systems since the early 70’s and have found that dry lube, if you use anything, is better than grease. I’ve always told my customers best is go dry and service annually.

Click to expand...

Your comments on the one that was dry and rusty were quite caustic when you saw it. Might be a regional thing where people in dry sandy places have different experiences than those on clay with wet winters and a need for irrigation in summer.

Rivets said:

because if you had and you have any common knowledge of what that drive gear is telling you, you would understand that lack of maintenance is causing wear and those gears need to be replaced.

Click to expand...

non-greased unit


greased unit - both same age, adjacent lawns same soil, same grass seed. same height, watering schedule, etc., and age (18 years).

Sg, there‘s a reason I attached a Toro drive systems manual in the eariler thread. If you knew as much as you think you know about Toro drive systems, you would know that that zerk is to lube the bushing only, one pump per year. More than that, as you show in your picture, means you are using more than you should, pushing grease past the friction washer, clutch ring and on the drive gear. Stick to what you know, not what you think you know. If you had read page 7-3 of the manual I sent you, when you were rebuilding that other $300 Toro, it cautions about over lubing these systems.

Rivets, I read what you sent. That is why I used grease instead of the dry lube you say to use. Are you saying the manual is wrong?

I’m telling you that the grease is for the bushing in the adjuster housing. Dry lube on drive parts. Manual is correct for those who bother to read them and understand how the drives work. You think all drives are the same and them make claims based on your false assumptions.

Rivets said:

I’m telling you that the grease is for the bushing in the adjuster housing. Dry lube on drive parts. Manual is correct for those who bother to read them and understand how the drives work. You think all drives are the same and them make claims based on your false assumptions.

Click to expand...

I hope your week gets better.

My week has been great, I hope you only post about things you actually know are correct.

FYI, mowed several times. - After installing/rebuilding (replaced damaged and worn parts) on front and rear axles the new height adjustors stay put and there appears to be a definite difference in the speed of the direct drive. Wow! Friction reduction and less stress on direct drive system. Like sgkent said the axle maintenance is likely missed with some folks. Will be cleaned /inspected every season and worn parts replaced. This may also explain why the right rear tire wears a lot more than the left rear tire. Will likely buy new tires also since the bolts holding the tires were severely worn. Therefore, old tires are little loose on new bolts. Thanks for feedback and all your help.

Thanks rivets for the feedback. It's kinda of like lube the chasssis of the car and pushing to much to blow the rubber seal. Mostly on trucks and why I do it myself.

Rivets said:

My week has been great, I hope you only post about things you actually know are correct.

Click to expand...

So much misinformation out there you are 100% correct.