# Gravely 8162-B PTO problem



## tigerwiles

Here's some history: Added 90W gear oil to transmission casing. Cut grass once (cut great) then was parked for the winter. Next grass cutting PTO seemed to slow down through meduim heigh grass (has never done this before....hmmmm). Next grass cutting PTO slowing down even on the lowest of grass height. Even forward motion is sluggish. Found out the gear crank case oil should have been SAE 10w-30. Drained it and added all new "correct" oil. Gravely service suggested I stay out of high grass until 90W is out of wet clutch. Did just that but after 3 cutting attempts and a several hours of run time, PTO still dies on even the shortest of grass. Even tried to change the oil AGAIN but no change. Does this mean I burned up my PTO clutch or will my baby come back to life once all the 90w is forced out of the clutch? Any suggestions will be greatly appreciated.


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## mark02tj

I use straight SAE-30 in mine, not multi-viscosity oils. But mine is older than yours. 

Good luck!!


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## Richard-tx

How is your free play?

I use 20-50 in all my transmissions and have been using it for over 15 years. Never had any issues. I do change my transmission oil once a year.


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## tigerwiles

<Richard-tx> If you are refering to how far the PTO travels (turning) left to right before engaging the gears, hardly any free play whatsoever. I'm afraid I burned up what was left of the 30+ year old clutch. Luckily I have a parts 8162-B. I'm going to pull the clutch out of that one (after vacation to PA) and wish for the best. I still have a hard time believing something as simple as the wrong oil in the crank case, and one mow, has cause me this much grief. I can still smell the distinct oder of gear oil when I drained the crank case (for the 3rd time). Maybe that thick stuff is still in the clutch. Has anybody ran an engine type cleaner in the crank case before? Or is it NOT a good idea?


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## Richard-tx

I think that the primary issue was a lack of free play in the clutch. I believe the spec is 1/2" of free play. You can check the spec in the manuals at OldGravelys.Net While the 90 wt didn't help matters and may have accelerated it , it was likely not the root cause. 

Given the amount of work involved in changing the PTO clutch, I would not put in a used clutch. Sure a new clutch is expensive, but if you plan on keeping it for another 30 years, it is the only way to fly. There is also the labor involved. The first time someone changes a clutch, the amount of time spent is usually between 15-20 hours. With practice, that time is reduced down to about 8 hours.

Another thing that shortens clutch life is engaging the PTO clutch at high engine RPMs. Use the lowest engine RPM possible when engaging the clutch.

If you have free play in the PTO control lever and it still slips then the clutch is gone.

One way to immerse the clutch in oil and thus flush it out is to overfill the transmission by a quart or two, run it for a while (30 minutes or so) and then drain the excess.

Using the wrong lubricant can result in more damage than you can imagine. Adding brake fluid to a hydraulic system is one example.


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## Richard-tx

One more thing, the smell of 90 wgt will be there a long time. The residual should not hurt anything.


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## tigerwiles

Thanks Richard-tx for all your time and info. I checked the free play in the PTO lever and I have none. In fact for years it taken some effort to get the lever to travel all the way forward (engaged). There's no problem pulling it back to disengage it but engaging is a different story. With your advice, I've decided to swap entire transmissions from my parts tractor with my current one. That way I'm not opening the casings on any of them. Besides, I don't have 15-20 hours to waste. Grass grows to quick. Hopefully the PTO clutch is good in the parts tractor and I'll get a few more years out of it. If not, oh well, I'll go back to plan B and buy a new PTO. I don't want to put my baby to bed just yet. She's still in good shape and runs TOOO good. She's been SO reliable until now.


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## Richard-tx

If you don't have any then adjust the rod until you do. You may just have to adjust the rod and you will be up and running again. My advice is to take the control rod completely out of the tractor and put it in a vise and use some heat to get the clevis ends to move. If you don't have a torch, don't bother to even attempt moving the clevis ends.


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## tigerwiles

Richard-tx you are the bomb!!! With a little help from some PB Blaster, I adjusted the clevis until I had about an 1 1/2" of free play (service manual say, "With PTO lever engaged (IN POSITION) there would be about 1 3/8"(3.5cm) to 1 1/2"(3.8cm) of free travel between the lever and the back of the slot in the cover plate"). To accomplish this I had to rotate the connecting rod 5 times ("For every complete clockwise turn of the rod, you gain .25" free play..."). At first I did 6 turns but then the PTO wouldn't disengage so I had to back it off once to get the correct adjustment. The PTO sounds strong now. Went through some thick precut grass and it didn't bog down. Don't want to prematurely celebrate yet though. In the past, about 20 minutes into cutting, the PTO started slowing down. I'll know it's fixed once the grass grows again and I do my usual 2 hour yard mowing (2 acres).
Thanks again for your help. You may have just saved me $700 - $750 for a new installed PTO clutch. Now all I have to do is get a brake drum seal. Leaking really bad.
Maybe this should be a new tread but do you know if the brake drum seal is installed from the outside or will the cover need to be removed to accomplish this? Haven't removed the drum yet to investigate.


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## Richard-tx

THanks for the kind words.

If you are referring to the axle seal, that is easily replaced once the hub or drum is removed. I have seen tractors with two seals installed per side. If worse some to worse, removing the axle housing is not hard. I have replaced axle seals while the axle housing is on the tractor. It is tricky to do since damage to the axle sealing surface means it will leak forever. If I recall correctly, the last axle seal I changed took under an hour.

Here are my tips for extending the life of a PTO clutch.

1 - Engage the PTO clutch with the engine RPMs at a minimum. Engaging at an idle is best.

2 - Maintain free play.

3 - The 50" mower deck is for mowing lawns, not brush cutting. If you have to cut tall weeds, raise the deck all the way up and make your initial cut, then lower it steps and make subsequent passes.

My advice is to be prepared for a new clutch. It may take a few (2-5) years before it is worn out, but it is a matter of when, not if.

Since you saved you a ton of money, spend a little of that on your tractor. Lube the direction clutches. Take the direction clutches off and clean the splines and coat the splined shaft with grease and reassemble. If the clutch bearing is rough, replace it. I think the bearing is a 6208 double sealed bearing and it should cost under $15 each for a NTN brand bearing. NTN bearings are premium bearings. If you call Accurate, ask for Tony.

As long as you are at it, grease your tractor. Don't forget the 3 zerks on the rack and pinion steering gear.

Also check your rear hub set screws. They do loosen over time. You have brake drums so it may not apply to you.

Proper maintenance is a seemingly thankless job, The rewards are fewer and less expensive repairs later. I have never seen anyone damage an engine from changing the oil too often.


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## tigerwiles

It's not the axle seals that are leaking. It's the one oil seal (#17913 - New #05613800) behind the brake drum (where the brake band assembly is located). I'm hoping the seal is externally installable. It looks like it is on the parts explode schematic (Number six shaft - brake/sliding gear). I really don't want to break the trans casing open.

Thanks for the maintenance recommendations richard-tx. I usually keep all the typical grease points lubed but as I had the tractor apart, I went ahead and greased(and adjusted) areas like the teeth on the gear rack and steering arms at the base of the stearing column. And a few other places. I'm not sure what you are refering to in regards to the "zerks" though. I didn't think about cleaning and greasing the clutch shafts though. I will do that before my next cutting.

I've had the shop & Ops manual for quite some time. Before this issue with the PTO, I didn't read ANY of the maintenance sections. I realize now I've been neglecting proper maintenance on my tractor. She's a tough beast but even the tough needs love for time to time.


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## gravelymay

tigerwiles said:


> It's not the axle seals that are leaking. It's the one oil seal (#17913 - New #05613800) behind the brake drum (where the brake band assembly is located). I'm hoping the seal is externally installable. It looks like it is on the parts explode schematic (Number six shaft - brake/sliding gear). I really don't want to break the trans casing open.
> 
> Thanks for the maintenance recommendations richard-tx. I usually keep all the typical grease points lubed but as I had the tractor apart, I went ahead and greased(and adjusted) areas like the teeth on the gear rack and steering arms at the base of the stearing column. And a few other places. I'm not sure what you are refering to in regards to the "zerks" though. I didn't think about cleaning and greasing the clutch shafts though. I will do that before my next cutting.
> 
> I've had the shop & Ops manual for quite some time. Before this issue with the PTO, I didn't read ANY of the maintenance sections. I realize now I've been neglecting proper maintenance on my tractor. She's a tough beast but even the tough needs love for time to time.



The brake drum seal is replaceable from the out side.
first pull the brake band off.
Then the drum. may need a puller.
Drill a small hole in the seal just through the thin metal on farther
screw a sheet metal screw into the seal and pull the seal out
Now put in the new seal.
the zerks are grease fittings


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## tigerwiles

Thanks - Gravelymay - It's good to know that I don't have to crack the trans casing to change a simple oil seal.

This is embarrasing but I've never heard of "zerks" being a grease fitting. I've been working on machanical stuff (cars, motorcycles, mowers....etc) since I was 13 years old (now 40+) and never knew a grease fitting is called a zerk. I guess it's true....Old dogs CAN learn something new.

Thanks again to everybodies input on my issue(s).


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## Richard-tx

The Zerk grease fitting was first invented by Oscar U. Zerk.


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## GravelyNut

tigerwiles said:


> Thanks - Gravelymay - It's good to know that I don't have to crack the trans casing to change a simple oil seal.
> 
> This is embarrasing but I've never heard of "zerks" being a grease fitting. I've been working on machanical stuff (cars, motorcycles, mowers....etc) since I was 13 years old (now 40+) and never knew a grease fitting is called a zerk. I guess it's true....Old dogs CAN learn something new.
> 
> Thanks again to everybodies input on my issue(s).


Zerks are only one type of grease fitting but the most common. Then you have Alemite fittings for large amounts of grease. Zerks you push the grease gun on to while Alemite fittings are such that the head slides on to a button type fitting.


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## Richard-tx

I only seen one piece of equipment that used a pin type grease fitting and I worked for over 5 years as a industrial mechanic on all sorts of equipment that very few have ever heard of let alone seen. I am not saying that they don't exist, just rare. I don't think I have ever seen a button fitting in the flesh.


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## farmertim

Funny,
I asked the question not too long back about Zerks and why they were called that, I did a little research of my own and discovered that they were named after the inventor of them.
In Australia (and I think the UK) they are always known as grease nipples.
Guys you are fountains of knowledge and it is guys like you that who share it that make this such a great forum, Thanks.
Cheers:beer:
:aussie:


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## tigerwiles

I absolutely agree with you <farmertim>. Got to love the people with the wealth of knowledge and willing to take the time to share it.


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## Richard-tx

farmertim said:


> Einsteins definition of insanity; doing the same thing repeatedly and expecting a different result


I believe he made that statement as a comment on WWI


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## Modelmaker

*Slipping clutch*

Richard-tx,
I have been following this thread with some interest, as it has also happend to me. I have been nursing my tired B+S 16 hp for many years, and finally installed a new Kohler 18 hp. on my tractor. Now my pto is slipping. I made the adjustments you suggested, and all seems OK. I believe that my old engine was so tired that it would bog down before the clutch would slip.
My question though, on a tractor with a healthy pto clutch, at what point would it start slipping?

I am new here, and have found this site to be a Huge help!
Thanks!


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## Richard-tx

What I have found is that it is pretty difficult to quantify when a clutch will slip especially with a mower deck. If I recall correctly, assuming a new clutch, the mower deck belt will slip just before the clutch does. That is definitely the case if the heavy clutch spring is installed.


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## tigerwiles

Just to give a quick update. The adjustments made on my tractor's (8000 series) PTO worked great. Mowed some thick areas of grass in the field and it didn't slip whatsoever. It bogged the engine (16 HP B&S Indust) a little but the PTO held strong. Sad thing is I KNOW this is my last time adjusting the PTO. I have very little free travel ("play") between the lever and the guild plate. I've tried to re-adjust it according but the PTO will not disengage. I'll baby it (cut grass sooner) as much as I can. When the day comes to replace the PTO clutch, I'll have the tough decision of whether to spend the $700-750 for a new PTO (installed) or put her to bed. Still damn good for a 34 year old tractor that has seen her fair share of TOUGH jobs and a little maintenence neglect. Thanks again everybody.


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## Richard-tx

Retiring the tractor is a tough decision. In all fairness, the PTO replacement can be done yourself for about $350 if you do the work yourself.

The way I look at it, if that is the only thing wrong with the tractor, a new clutch will last 30 years or so. Dirt cheap as I see it. The new electric clutches won't last anywhere near that long and are almost as expensive.

Lets say you have the job done by a mechanic and it costs $750. Over 30 years that cost is $2.09 per month.

A new tractor will cost you at least $10k for something comparable in quality.

Spend $750 or $10k? Easy decision.

If it were me, I would keep an eye out for a nice low hours G series tractor. Should be able to find a nice low hours G for under $2k. I paid $350 for my G. Then I could repair the 8000 at my leisure and have a spare. I could also shop around for a nice used clutch and lower the price even further. 

I have a 8000 as well as the G. I think the G is more refined.


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## tigerwiles

That's a good point <Richard-tx>. $2.09 a month is dirt cheap. It's definitely something to consider. I definitely have the ability to put the new clutch in myself. It's the time I really don't have. I still have my other parts tractor (another 8162-B) with a complete tranny intact. Worse case I'll take a couple hours and swap it. Not sure how many hours is on my parts tractor. There's no meters on either one of them. Might be a waisted 2 hours of my time. It's a chance I'll decide to take when the time comes.


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## gravelymay

Hi
There was a dealer at the Mowin that is having the Pto clutch redone.
He said he could sell me the main and two cups for $250.00.Bye
Since He is a dealer I don't know if he wants it broadcasted.
I will be glad to spread the word off the club.
Give me a call or
e-mail [email protected]
Thanks Bruce g


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## kenparadis

*PTO problem on 8162-B Gravely*

All the problems that I see on this forum are clutch failures. My problem is the opposite I can't seem to disengage the PTO clutch. At this time I have the transmission open , so if anyone has some idea(s) I am all ears (in this case maybe eyes) Thanks in advance! Ken in NH [email protected]


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## Richard-tx

If you have the transmission open and I hope the transmission is still on the tractor, then the PTO clutch shaft has to come out. Once it is out, then a disassembly of that shaft is needed. 

Be advised that the spring on that clutch is wicked dangerous and that improper disassembly can and does result in injury or other broken PTO clutch parts.

I use the later G series service manuals available at oldgravelys.net when servicing the transmission.


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## tigerwiles

Just an update on what has happened in the.....OMG.....2.5 years since the PTO problem on my 8162-B. I did take a couple hours and swapped out my tranny for the one off my parts tractor. And as I expected, a waste of time. It was worse than my original tranny. The PTO was better but there was something wrong with the gears inside it (a whole lot of noise and grinding going on). So I decided to put a new PTO in my original tranny. A Gravely service center in Jacksonville, FL said they would rebuild it for me for $200 since I was supplying all the parts. Plus the owner was familiar with the old Gravely's as I was not. It took them longer than expected to get the new PTO installed but nonetheless, she's all done. She cut grass like a dream. Deck blades sound like a turbo when the PTO is engaged (still having problems adjusting the PTO lever so it's not resting on guild plate. not sure what's going on there). Ran through some pretty thick grass without a single slip. Awesome!! UNTIL.........her heart started beating erratically. The 16HP B&S was popping out the muffler really bad. Had plenty of good gas and fuel pressure. Thought it was a carb problem so swapped it out with my spare. Still the same problem. Rebuilt the carb, still the same problem. Then had it checked out by a local guy that does small engine repair. He said it was blown up. Frustrated.... I pushed her in the garage and covered her up. Now I have *$$$$$$* into a new PTO with nothing to push it with. #[email protected]$


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## Richard-tx

Change the condenser.


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## tigerwiles

I changed the points, plug, condenser and coil just about 3 weeks before she started acting up. I checked the compression myself and she had 110 psi. She's not blown up. The local guy is full of it. Good thing I didn't take his word for it. Anyways took it to a guy that rebuilds engines (which he even confirmed, with 120 psi, that the engine wasn't blown up) where he converted it to electronic ignition. She's running again. Very strong and no problem cutting thick grass again.
The condenser was probably the problem with it from the start. Goes to show, with anything that is electronic, even brand new can go bad quickly. But now I don't have to worry about point and condenser now. Now if only I can find the slight miss during idle.


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