Rotary mower gearbox input seal. How often gear oil change?

[CobyRupert]

Have a Frontier 2084 7’ rotary mower. 6 years old. Gets used maybe 6-8 hours a year.
This year when i go to hook up, there’s an oil trail out of front input shaft. It’s never leaked oil before. Never saw any leaks prior to putting it away last year.
Do you think seal got a leak sitting over winter? It did sit in a place that gets sun (heating /cooling cycles).
How do I test that “breather bolt” / oil fill plug on top of gear box works?
Is changing input seal hard?

I don’t know yet how fast leak is.

Btw: How often do most of you change rotary mower gearbox oil?

 

[RedNeckRacin]

I just replaced the output shaft seal in my mx10 for the second time. The hardest part is getting thr stump jumper and blade holder back onto thr shaft. Your input seal should be alot easier if not for the simple fact you can work on top of the mower instead of under it. I think my breather got plugged last year and my gearbox drew some water because when I broke the castle nut loose a few ounces of water came pouring out. I am going to start taking my air compressor and blowing out the passages in the breathers before winter. I would have to check my manual for the mower again but the change intervals are not to often.

 

[CobyRupert]

I’m not sure how to replace seal (part #7)
Do I take off cover plate around input shaft (green bolts) ?
Does this plate hold input bearing and seal in place?
Simply a matter of removing plate, seal falls off or out, pop new one in?
My projects are never that simple.
Do I have to drill and pull seal out?

 

[CobyRupert]

My manual says “Storage: At end of your cutting season: 1. Drain and change the oil in the gearbox.”
I never have.

 

[Bigfoot62]

My manual says 鉄torage: At end of your cutting season: 1. Drain and change the oil in the gearbox.
I never have.

Me either.

But, look on the bright side: If the seal is leaking and you keep adding oil, that's basically changing it, right? Just kidding.

I would suggest, instead of changing the seal right now, top it off with 85W-140 and finish the season. Change it this winter, after you're done mowing.

To change the seal, it's pretty straightforward. Remove the 8 bolts that hold the front cover (faceplate) on. Remove the front cover. You may need to use a putty knife, sharp screwdriver, etc. to get it started. The input shaft will stay put, just slide the cover over it. The seal should come out of the back side of the cover. Remove the old seal. Install the new seal. It needs to be pressed in, or use a seal driver of the appropriate size. (a 3/4" drive socket, the same diameter as the seal, will do) AFTER you clean and de-burr the input shaft, re-install the front cover. If you don't remove any burrs or rust from the input shaft, you may damage the new seal. I like to use emery cloth to shine it up. I don't see a gasket or O-ring on the front cover. It will need to be sealed to the gearbox. If there's nothing there when you remove it, I would use Permatex #2. You could use RTV (silicone), but it has to be really clean, and then nothing else will ever seal that joint again. Re-install the driveline and guards. Fill the gearbox with oil.

 

[CobyRupert]

Me either.

But, look on the bright side: If the seal is leaking and you keep adding oil, that's basically changing it, right? Just kidding.

I would suggest, instead of changing the seal right now, top it off with 85W-140 and finish the season. Change it this winter, after you're done mowing.

To change the seal, it's pretty straightforward. Remove the 8 bolts that hold the front cover (faceplate) on. Remove the front cover. You may need to use a putty knife, sharp screwdriver, etc. to get it started. The input shaft will stay put, just slide the cover over it. The seal should come out of the back side of the cover. Remove the old seal. Install the new seal. It needs to be pressed in, or use a seal driver of the appropriate size. (a 3/4" drive socket, the same diameter as the seal, will do) AFTER you clean and de-burr the input shaft, re-install the front cover. If you don't remove any burrs or rust from the input shaft, you may damage the new seal. I like to use emery cloth to shine it up. I don't see a gasket or O-ring on the front cover. It will need to be sealed to the gearbox. If there's nothing there when you remove it, I would use Permatex #2. You could use RTV (silicone), but it has to be really clean, and then nothing else will ever seal that joint again. Re-install the driveline and guards. Fill the gearbox with oil.

Thanks for the advice Bigfoot.

That's exactly my plan. I added 85W-140 and ran it for a couple hours. Some leaked, but a little always looks like a lot and makes me nervous. I think the root of the problem is a bad breather vent in the fill plug.
When I loosened the plug the other day after the sun came out, and again after using it, I can hear pressure escape. This is what probably made the seal leak over winter. Don't know why breather plug would stop working, even after I tried blowing it out with air. Doesn't seem to leak as bad once pressure is relieved.
I ordered new breather plug and input seal.

If I get over my head, I hear filling gear box with "corn head grease" is an option to replace leaking oil.

What do you mean by "nothing else will ever seal that joint" again if I use silicone?

 

[LouNY]

On many gear boxes if the seals leak just a bit we will give them 20-30 pumps of grease to mix in with the gear lube.
Quite often the breathers will get plugged up and some spray brake clean and or a soak in a bit of gasoline then an airhose blow and they will be good to go again.

 

[the old grind]

If you've changed enough seals and aren't confused by the #7 in second pic pointing to the gap behind it vs the seal itself, you oughta see you shouldn't have to remove any bolts to replace the seal.

First pic shows "ready R&R the seal." I haven't slept in a Holiday Inn lately, but I replaced a lot of input & output seals (hundreds) working leak-test/repair in a GM transmission plant in the early '80s. Scoring or porosity in a seal bore can be fixed using any old-school rawhide glue or Permatex #1.

Study your pics well before you take apart stuff you didn't need to. The importance of a 'fix' should never make 'getting it right' more difficult by 'technical intimidation'. This one should take 15 min at most. Starting a seal into bore may be the tricky part if you don't have a 'driver' to hold it on-center or 'the touch' for it. Buff the shaft with steel wool as best you can reach where the seal's lip seats. 'You got this.'

 

[CobyRupert]

If you've changed enough seals and aren't confused by the #7 in second pic pointing to the gap behind it vs the seal itself, you oughta see you shouldn't have to remove any bolts to replace the seal.

First pic shows "ready R&R the seal." I haven't slept in a Holiday Inn lately, but I replaced a lot of input & output seals (hundreds) working leak-test/repair in a GM transmission plant in the early '80s. Scoring or porosity in a seal bore can be fixed using any old-school rawhide glue or Permatex #1.

Study your pics well before you take apart stuff you didn't need to. The importance of a 'fix' should never make 'getting it right' more difficult by 'technical intimidation'. This one should take 15 min at most. Starting a seal into bore may be the tricky part if you don't have a 'driver' to hold it on-center or 'the touch' for it. Buff the shaft with steel wool as best you can reach where the seal's lip seats. 'You got this.'

I'm sorry for my ignorance, but what do you mean?

I still have to take off the cover plate (green bolts) to replace seal? That is, do you agree with Bigfoot's assessment that cover comes off then seal comes out backside of cover?

(Note: the 4 silver bolts shown in picture previously held a pto guard/housing in place).

I don't understand the diagram showing "phillips screw heads" (?) where the bearings are, but I don't think this doesn't matter in regards to the seal. Right?

What do you mean by "ready R&R the seal"?
and
"Scoring or porosity in a seal bore can be fixed using any old-school rawhide glue or Permatex #1."? - I still need to replace seal right?

 

[LouNY]

Many seals will drive in from outside a gear box,
looking closely at your picture it looks like that one may.
If it does, I have collapsed them and peeled them out,
many people have success running a couple of screws into the seal then prying them out.
Once out one of the hard parts is sliding the new seal over the shaft without damaging it,
then keeping it square in the bore as you tap it in.