Series Overdrive Wear

**B.S.F.** · 25th September 2012, 07:41 PM

If the inside of your Toro has got chatter marks ,it is possible to press in a thin needle roller bearing and remove the bearing on the clutch sleeve.The bearing no. is A5020Z, dimensions 52x58x20 mm. A bearing shop should be able to get one for you. W. TLA-5020Z Needle Roller Bearing 52x58x20 IKO

**isuzurover** · 25th September 2012, 08:07 PM

Originally Posted by Tank

I am talking about the bearing surface on the inside of the main gear/shaft which either needs to be repaired or replaced, cost of machine shop work makes it cheaper to buy a new shaft, regards frank.

Frank, it is impossible to tell from those pics. Looks like grease/residue from me.

Most ODs have so much NVH anyway, I doubt the OP would notice the difference.

**Tank** · 26th September 2012, 01:47 AM

Ben, Aleksei seems to agree that there are chatter marks and by the amount of rust in there it doesn't look like it's had much oil in there. The chatter marks are the result of not enough oil for the roller bearings in the clutch sleeve and when it gets bad (and noisy) the engaging teeth on the clutch sleeve wear and you end up with no drive. I had one and packed it with grease and kept oil up to it, but it finally failed as above, they need oil holes drilled from the outside of the shaft to let oil into that area, Regards Frank.

**Killer** · 26th September 2012, 06:04 AM

Originally Posted by Tank

I am talking about the bearing surface on the inside of the main gear/shaft which either needs to be repaired or replaced, cost of machine shop work makes it cheaper to buy a new shaft, regards frank.

Assuming you can get a new shaft. I have not heard of anybody making new parts for the Toro.

Cheers, Mick.

**Krafty_Lucas** · 26th September 2012, 07:21 AM

Thanks for the advice gents. I'm not too concerned about additional nvh, that's what earplugs were made for! A needle roller bearing on the inside of the shaft might be the way to go. As advisedI'll take it to an engineering joint and get their opinion. I'm planning to strip the whole unit, so no doubt there'll be more questions to come.

Cheers,

Aleksei

**B.S.F.** · 26th September 2012, 11:27 AM

Originally Posted by B.S.F.Nut

If the inside of your Toro has got chatter marks ,it is possible to press in a thin needle roller bearing and remove the bearing on the clutch sleeve.The bearing no. is A5020Z, dimensions 52x58x20 mm. A bearing shop should be able to get one for you. W. TLA-5020Z Needle Roller Bearing 52x58x20 IKO

Just to illustrate my post. The bearing on the left is the replacement bearing A5020Z the one on the right the standard one. W.

**wagoo** · 27th September 2012, 04:08 PM

The chatter marks inside the output gear are due to not using overdrive gear often enough.In direct drive the lack of a speed differential between input shaft and output gear causes the needle roller bearings to Brinnell into the bearing surface of the output gear.The thin walled roller bearing suggested by BSF will still suffer this Brinneling in time but at least is replaceable. The alternative is to delete the roller bearing and substitute it with a bronze bush.With overdrive ratio selected there is only around 1000rpm speed differential between in and output shafts at 4000rpm in 4th gear and bronze bushings don't Brinnel.It is likely that the needle rollers would settle into the chatter marks of the output gear and just skid around the clutch sleeve anyway, so may as well have a proper bushing.
I succesfully use a bronze bush in that application on my crawler reduction box, and the side loadings with the 2.6:1 reduction is considerably greater than a 27% step up in an overdrive.
I hand file a sort of spiral on the outside diameter of the bronze bush to assist in feeding oil into the clutch sleeve and input shaft splines.Sort of an Archimedes screw pump.
Bill.

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