Back-lash on Superior gearbox.

[Scraperman]

I just wondered if anyone is able to help please ? I have an elderly Scag Turf Runner and at the moment I have the Superior gearbox fitted to the deck. I do have a Curtis gearbox in for repair. Yesterday I heard a different sort of noise coming from the deck and after checking I think there may be too much play between gears in there somewhere. But I have already taken the main T gearbox apart, which is also a Superior gear box, some time ago when replacing the electyro-magnetic clutch and there were no shims in there but the back-lash was O.K. But I have just looked at the parts diagram for the deck gearbox and it doesn't show any shims in there either.

I have got the deck box on the bench ready to dismantle but I wondered if anyone could tell me if the back-lash for the gears in there is in any way adjustable ? Thanks in advance for any help and/or advice.

 

[sgkent]

if it is adjustable you should find shims or some kind of hub with threads that lets you change the lash by changing the ring gear to pinion clearance. If neither the pinion or differential gears have such an arrangement, it won't be adjustable unless the parts book shows different pitch or thickness gears. If the gears are worn, it may be as simple as just ordering new gears and packing them with fresh grease.

 

[StarTech]

The OP would need to take a loan if he ordering parts from Scag. He might able to get the cones and cups along some seals but will even take quite a bit research.

 

[Scraperman]

if it is adjustable you should find shims or some kind of hub with threads that lets you change the lash by changing the ring gear to pinion clearance. If neither the pinion or differential gears have such an arrangement, it won't be adjustable unless the parts book shows different pitch or thickness gears. If the gears are worn, it may be as simple as just ordering new gears and packing them with fresh grease.

Thank you for that. I have s strong suspicion that there isn't any means of adjusting the back-lash but I am going to take the top off the gearbox this morning and will report back.

 

[Scraperman]

The OP would need to take a loan if he ordering parts from Scag. He might able to get the cones and cups along some seals but will even take quite a bit research.

Whenever I need oil seals or bearings I go to my local factors and there is never a problem with them. I am only 4-5 miles from the U.K. importers of Scag equipment and in fact I once worked with the chap who started that business but who is sadly no longer with us. My mower, a Turf Runner is, as I discovered after buying it, the one Scag item that you shouldn't buy. But that was 23 years ago when I bought it at an auction of s/h equipment and so it wasn't new then. I only mow about an acre per week round the house and farm buildings and I have suffered quite a bit of grief over the years but it's a cracking machine to use with zero turn, collect or side discharge etc. But in resposne to your remark alluding to the price of spares, I have recently needed to replace the electro-magnetic clutch and I had to mooch around quite a bit to find an equivalent item at something like a reasonable price.

 

[StarTech]

It is good that you have a reliable source for seals I kinda wish I did at some the prices JD wants for their seals.

Yes most OEM electric PTOs are over priced. Thanks that I can buy from Warner Direct, Xtreme, and OxClutch at reasonable prices when compare to the OEM ones.

My comment on prices were in reference to Scag wanting to sell assemblies instead individual parts like the bearings and seals or at least the IPLs I looked at show them that way only. This where a resourceful mechanic has an advantage over to the DYIer most times.

 

[Scraperman]

It is good that you have a reliable source for seals I kinda wish I did at some the prices JD wants for their seals.

Yes most OEM electric PTOs are over priced. Thanks that I can buy from Warner Direct, Xtreme, and OxClutch at reasonable prices when compare to the OEM ones.

My comment on prices were in reference to Scag wanting to sell assemblies instead individual parts like the bearings and seals or at least the IPLs I looked at show them that way only. This where a resourceful mechanic has an advantage over to the DYIer most times.

Not sure where you are but here in the U.K. we have many firms selling seals, bearings, belts, etc. etc. e.g. https://www.accesseng.co.uk/ and they can be very useful and helpful. I would have preferred to buy a Warner electro-magnetic clutch because that was the manufacturer of the original fitted to the mower but it was going to cost a fortune with the shipping as well.

Now for something quite bizarre. Once I had got the gearbox set up on the bench I tested the back-lash as best as I could and I honestly don't think it needs to be any tighter. I started to dismantle the box anyway but the engineering is so complex that I have decided that I am not going any further with it. I won't go into detail unless anyone wants to know but it is shown below and to remove the top of the gear box items 10 & 11 have to be removed which entails undoing 20 socket headed cap screws (item 5 & 6). They were so tight that I had to use a length of tube on the Allen key and some would loosen, some wouldn't without shearing the cap screw. And you can only use an open ended spanner on the nuts, a ring spanner or socket won't go on !!!

 

[Tiger Small Engine]

Not sure where you are but here in the U.K. we have many firms selling seals, bearings, belts, etc. etc. e.g. https://www.accesseng.co.uk/ and they can be very useful and helpful. I would have preferred to buy a Warner electro-magnetic clutch because that was the manufacturer of the original fitted to the mower but it was going to cost a fortune with the shipping as well.

Now for something quite bizarre. Once I had got the gearbox set up on the bench I tested the back-lash as best as I could and I honestly don't think it needs to be any tighter. I started to dismantle the box anyway but the engineering is so complex that I have decided that I am not going any further with it. I won't go into detail unless anyone wants to know but it is shown below and to remove the top of the gear box items 10 & 11 have to be removed which entails undoing 20 socket headed cap screws (item 5 & 6). They were so tight that I had to use a length of tube on the Allen key and some would loosen, some wouldn't without shearing the cap screw. And you can only use an open ended spanner on the nuts, a ring spanner or socket won't go on !!!

View attachment 70669

I have rebuilt a Superior gearbox before, only for it to leak again years later. Put in OO Cornhead grease and problem is solved for leaking.

 

[Scraperman]

I have rebuilt a Superior gearbox before, only for it to leak again years later. Put in OO Cornhead grease and problem is solved for leaking.

Thank you for that. I have heard of that dodge being done but never done it myself. Could I ask a few questions about it please ? Does that sort of grease handle like normal grease ? If so how you get it into a small gearbox like on a mower deck ? If you fill an old type manual grease gun I presume that you can just keep squirting it into the gearbox but how do you know when you have got enough in there and how do you check the level once the mower has been used ?
Sorry for my ignorance but it just seems like a feasible alternative.

 

[Tiger Small Engine]

Thank you for that. I have heard of that dodge being done but never done it myself. Could I ask a few questions about it please ? Does that sort of grease handle like normal grease ? If so how you get it into a small gearbox like on a mower deck ? If you fill an old type manual grease gun I presume that you can just keep squirting it into the gearbox but how do you know when you have got enough in there and how do you check the level once the mower has been used ?
Sorry for my ignorance but it just seems like a feasible alternative.

It comes in squeeze tube like 80W-90 oil with small tip. It is thicker at normal temperature and then thins out when equipment is running and then thickens up as temperature returns to normal.