Changing the gear oil in a Kuhn GMD 600 - Question???

[Bigfoot62]

I have two hay mowers, both are Kuhn, but one of them is green.
Kuhn GMD 600 GII HD
John Deere 265
Except for the color of the tarp (curtain) and paint, they're the same. And the Kuhn has the HD hats.

I was cleaning up the 265 yesterday, and then drained the cutter bar and gearbox oil. Had the plugs removed from both, and the bar was in the upright position. I re-installed the drain plug on the bar, and then brought the oil level up to the top plug. That's when I noticed that the new oil was draining from the gearbox. Didn't know if that was normal or not. I don't think that I've ever drained both at the same time.
So, the question is: Is that normal? The gearbox and cutterbar oil aren't separated by a seal? I would just change the oil in the other mower and see for myself, but it's broke down and not hooked up to a tractor right now. (See Part 2 below)


Part 2:
I was running the Kuhn when I started cutting Wed. Started smelling the belts burning. I shut it down and removed the belt cover. That's when I noticed the drive pulley out of alignment. Bearing gone out on the drive shaft.
So the question is: Is this a DIY project, or should I take it to the dealer and save the skin on my knuckles?
If someone has done this repair DIY, would you give me some pointers? I'd like to know your experience, and if you found out what NOT to do!

Thanks in advance for your replies.
And forgive me if I'm beating a dead horse. A search of this forum didn't turn up anything.

 

[RickB]

TBN is a popular busy site but real farmers hang out on the various forums here:
Viewing a forum - Machinery Talk
From memory only, the gearbox and bar maintain their own oil supply. There is no other way to keep oil in the gearbox and not flood the bar. If you have the tools and talent to get that multi groove pulley off the input shaft the rest of seal replacement is not too bad.
Unbolting the gearbox from the bar will release it, the output shaft is splined and floats in a gear that drives the bar. Again this is from memory and we all know how that can go.

 

[Tx Jim]

I agree with RickB there's a seal(key 11) separating oil compartments between gearbbox & cutterbar on the 2 mentioned disc cutters

 

[Bigfoot62]

Rick and Jim,
Thanks for the replies.

Couple of follow-up questions:
On the 265
Jim, the parts diagram is from the JD website, right?
Am I opening up a can of worms here? I mean, the oil that I was putting into the bar was running out of the gearbox in a stream. I would think that a "leaking" seal would just seep, not gush. Wondering if there are bigger problems, like a bad bearing, etc.
Crazy thing is, the mower was working fine. This machine is probably 15 years old or more. I've turned the hats around, and replaced the skid shoes, and it's to the point where I'm about to replace the hats with new ones. But, I've never been into the bar or gearbox.

On the GMD 600
My cousin looked it up, and it seems that Kuhn sells only the complete drive unit. I'm thinking that the bearings can just be replaced, as long as the shaft is good, correct? Or am I just wishing?

 

[Tx Jim]

Yes parts photo is from JD parts site.

 

[Bigfoot62]

OK, I'm fessing up and wearing the dunce hat.

I removed the vent plug for the cutter bar. (located in the lower part of the gearbox housing. The mechanic said that, "Of course, the gear oil would run out with that plug removed." :duh:

Ran the mower today and all is well.