I have 7u 40xxx with the oil clutch that has some "problems". I took the cover off and there's a variety of keep it going fixes in there. I have 7u 17xxx with a good clutch and linkages. Looking through the parts book it looks like some of the linkage arms are different between the two but it seems like the whole assembly should swap in.
This machine only gets about 20 to 30 hours a year so I'm thinking this would be an economical quick fix. I'm just not sure if all the pieces will interchange.
Not to familiar with the oil clutch so I'm not sure how much it would cost to rebuild or on parts availability. 
Any help with parts interchange and recommendations on rebuilding versus just changing to dry clutch appreciated. 
Tractor should be in the shop in the next day or so and then i can get the cover off and see how bad things really are.

Hi d2gary,
I just went back the other way dry to oil (oil originally),
1 you have to split the engine from the gear box dont forget to undo oil pickup as it is bolted to the g/b housing and oil clutch housing
2 remove old oil cluch housing
3 remove and replace flywheel
4 remove and replace arms on top g/b housing
5 install clutch pivot
6 install bottom pin for other clutch pivot arm
7 install dry clutch components as there is no side hole to tighten bottom bolt on clutch yoke (mine was welded)
8 reinstall engine
9 adjust all linkages
10 hope it works

In simple words not easy

Hope this helps

Regards

Well looks like quick and economical are definitely out of the question.
I was able to push the tractor into the shop after a quick bath. Just looking in from the access cover it seems like the bolt fell out of the bottom of the yoke. The clutch wasn't slipping it just quit engaging, very suddenly. The linkages are all still connected but the yoke looks kinda funky. I'll have to drain the oil out and see if I can get a better view of what is going on.
Thanks rax200 for the detailed info, numberc10 is my favorite

Hi d2gary,
here are a couple of photos of the oil clutch,

 
 
 
 

regards

Just like we were discussing regarding the forum upgrade thread. The oil clutch "upgrade" was a giant step backwards.

There is nothing wrong with the dry clutch setup. The parts are so robust that it will never wear out if maintained properly. It is just difficult to adjust on the D4. If they had made it like the D2 with the button instead of the clamp bolt it would have been better.

I knew a guy who sent his D4 in to an independent shop.and it came back with an "oil clutch". I don't know if they used a different clutch disk but they just dumped oil in it.

Thank you for the pictures rax200, I was looking through the servicemen book and what I was seeing didn't look like what I saw through the inspection cover. The pictures you posted look like whats in my book and the actual clutch l have looks like a standard dry clutch. The case is definitely a case that started life as an oil clutch. Like 8C 361 said I think someone just unknowingly filled it with oil, kinda like I did. I never had problems so I just topped off the oil. This will make my job a lot easier since I have a parts tractor with a complete clutch assembly with good linkages.
Thank you for the information

I don't know the history of this machine so I can't say if someone changed the disc to a different material or if it's just the standard dry disc.
I've never experienced any slippage or other problems with the oil in the clutch compartment. The tractor doesn't get a lot of run time so maybe extended run time might show more symptoms. I did use the Cat spec oil but I don't think I would chance it on any of my machines. Not to mention the oil really stinks and it's not cheap.

I got the inspection cover off and found the top bolt in the yoke is pretty hogged out and has been welded in. I feel like the bottom bolt , that I suspect fell out, will have the same treatment.

Those are great photos of the clutch Daryl - even the boots!

I'd love to know how running oil in a normally dry clutch changes performance (life, clamping etc). Fascinating.

Paul.