861 PTO/transmission seals

I recently purchased a '61 861, when I received it the transmission was way overfull causing leaks from almost everywhere. Once I pulled the check plug and drained it down (about 2 gallons) the leaks stopped. I then had the PTO shaft out to replace the rear seal which drained all the diff and hydraulic fluid which got replaced with new when I put it back together. I recently noticed the transmission started leaking from the side of the case (slotted screw below left foot board). When I pulled the check plug about a half gallon of fluid came out, coincidentally my hydraulics were about a half gallon low. This has happened twice in the past few weeks. I am guessing there is a PTO (or other) seal between the transmission and the hydraulic case that is leaking hydraulic fluid into the transmission. I can not find a drawing or any info anywhere about this or how to fix it. Any help is appreciated. Thanks.

There is an internal hydraulic pressure tube in the transmission case. Some have been known to split. Others have recorded on this forum for repairs.

I had not heard of that issue before, I will research it. As I have not been using the tractor other than a few short drives around the yard I was thinking this was happening while it sits and hadn't considered a pressure leak. I assume when I search this problem I will find a test to determine the cause? Thanks for the quick reply.

Here's a thread for you to review.

https://forums.yesterdaystractors.com/viewtopic.php?t=1392612&postdays=0&postorder=asc&start=0

I appreciate the help, I've read a lot of info on it now and have a pretty good idea how to tackle the line replacement if needed. I'm guessing it's really just the pressure line that would be a problem? I drained the transmission over night and removed the top cover, from what I see the lines are in excellent condition and there is no rust anywhere in the case. My plan is to check the empty drain pan I put under the tractor last night to see if any large quantity of hydraulic oil has seeped into the trans case. If it's relatively dry that should indicate the seals between the case are ok. The next step would be to start the tractor and look for leaks/fluid coming out of the line in the case. I am guessing I don't want to have the tractor running for long with no trans oil but if there is a line leak it should show up pretty quick? I want to diagnose the problem before throwing parts at it. Any ideas of other things to check or better ways to diagnose? I was looking at Brokentractor.com for the replacement line but have not heard back from them to confirm if the new line is turned down to the correct diameter(s). I have to ship to Canada so its pricey and I want to make sure I get the correct part first try and don't have to spend more money locally to get it machined. If anyone knows a good supplier please let me know. Thanks

Be sure to block the clutch pedal down if you plan to run the engine with no oil in the transmission. Even if it is in neutral the input shaft will still spin.

Good recommendation, Thanks. After leaving the tractor with the trans plug removed there is a decent amount of fluid that has continued to drain out, maybe 1/4-1/2 cup. It could be just running off the gears etc. but I would have thought after almost 24 hours it would be done with that. I clamped the clutch pedal down and started the tractor and ran it for maybe 5 min and could see no fluid coming off the pressure line. I shut it off an left it for a few hours and it continued to drip but no more than it did before, I could not see any additional fluid in the case. I ran it again with the 3 point arms chained down to get the hyd pressure up to where it was bogging the engine. Still no leaks or additional fluid in the trans case. With the lines looking so new and no obvious spray or leaks from them and the continual dripping, I have to assume there is a seal between the trans and hydraulic cases that is leaking. Has anyone encountered this before or know what it could be and/or how to fix it?

Yes I rebuilt the transmission. You could get the seal with a rear split the transmission I was working on had other issues.

https://forums.yesterdaystractors.com/viewtopic.php?t=893860&highlight=tube

This is the post where I came up with a way to extract the pressure tube. I removed the pressure tube no leaks I found the issue was the hydraulic sump was leaking into the trans sump. It was the seal on the lower shaft the upper shaft does not have a seal.

I have done front split before but never rear, I assume its a similar procedure? Any thing to be aware of that makes it easier or harder? I am guessing the lower shaft is the PTO, is there specific name or part number for that seal? I have looked at the parts diagrams but can't make out which seal I would need. Is the seal replaceable with just a split or does the trans have to be torn down? Is the seal on the inside or the outside of the trans case? Thanks.

I would have to see a diagram to refresh my memory I think the seal is in the PTO support. The seal runs on a sleeve that's replaceable and exspensive....

Altho you can't really see it, the PTO shaft seal resides in this housing that's bolted off the end of the transmission and sticks into the hydraulic sump. You can see this thru the side cover on the hydraulic compartment.

Don't worry about the two seals between the transmission and hydraulic. The fluid level is the same between the two. A bad seal there is not causing your troubles. If your transmission is filling up with oil, it's an issue with the hydraulic tube that runs thru the transmission. Run your tractor with the transmission cover off and oil in the hydraulic compartment, you'll spot the issue. Be careful and don't get run over.

In my case it was the seal...I replaced the tube the old one was good... I have no other explanation for it other than the seal was leaking into the trans sump.

I did not question the owner I went straight for the tube after no issue found his issue was the same as the poster. I mis-diagnosed it : ( I think he said his issue happen while the tractor was parked he kept adding fluid to the hydraulic sump the trans sump would overfill and leak.

His shifter was badly worn and I thought there was a leak between the trans and sump. To get the shifter and linkage the trans needed to come out. No doubt the seal ware sleeve was badly worn in the end rebuilding the trans was the fix the tube had noting to do with his issue...

The replacement seal was haft as thick as the original so I used two seals and turned each toward the sump they were sealing. I spec this is rare but possible so I would have to go with the belief the poster has diagnosed it proper.

I am questing if the pressure tube can be pressurized with air to confirm a leak while its in the tractor. I see no reason why it could not be. ? Its easy to remove and problematic so its not a waist of money to yank and replace.

Would it be possible to access that PTO housing and seal from inside the hydraulic case with the top off or is splitting the only option? I'm not sure one is any more work than the other though. I have the trans cover off and have ran the tractor (with the clutch pedal clamped down and in neutral) and even with the 3 point arms chained down and the engine bogging from the hydraulic pressure there are no visible leaks on the hydraulic lines. They look like new, there is no hint of rust anywhere in the trans. I've had the tractor sitting with the drain plug out for 2 days and it's dripping about a half cup of fluid per day with it just sitting. That makes me think its a seal. That said, if the 2 cases run close to the same level of fluid they should equalize which shouldn't be a problem? I did find that when the trans was just slightly overfull oil would leak from the foot board studs and the slotted shifter detent cover screws(?). I removed all of these replaced the degraded fiber washers with o-rings and thread sealed them. I'm hoping this will stop the oil leaks and allow me to ignore any possible seal leaks. I will still have to watch the trans oil level to make sure it doesn't get way over full indicating a line leak. Does this sound like a reasonable course of action?

A leaking seal isn't going to cause the transmission to be 2 gallons overfull as you stated in your original post. I am thinking that both the the suction line and the pressure line have small pinholes, most likely on the bottoms of the tubes where you can't see them, and when you are running it with the trans sump dry the pump is sucking air so it can't provide the pressure/flow required to push fluid out of the pressure line. Try adding enough fluid into the trans case to cover those lines in the bottom and run it and make sure that the 3 point lift is working, prime the pump if you need to, and then see if the trans case fills with fluid while it's running.

I did not think they ran at the same level you should be able to tell. Someone here made a pipe to go from sump to sump at the fill plugs that's a thought to keep it equalized.

I don't know the answer to the other question other than I commend ya on your diagnostic approach.

I have been dig'N this is a post from 4/09/2013

https://forums.yesterdaystractors.c...postorder=asc&highlight=level&start=0

I have sealed up all of the plugs and studs that go into the case and refilled the trans. I am going to monitor the trans and hyd oil levels for the next few weeks and see what happens. If it doesnt leak externally Ill be happy. Hopefully if the trans is a bit over full it wont hurt anything. Given the amount of oil it continually leaked over the few days I had the drain plug out I feel confident its the seal and not the hyd lines. I may not have mentioned that when I purchased the tractor it had just been split and supposedly had a new clutch put in. My initial guess when it was way over full was that whoever did the work filled the trans full as the oil looked new. Once I get rear tires I can put this tractor to work and that should confirm whether or not its the hyd lines. Thanks for all the help.

COOL