JD 970 PTO clutch

rojo · Mar 5, 2008

I recently purchased a JD 970 and believe the PTO clutch might be out. The drive clutch seems to work fine, although it seems a little long on the clutch pedal. It never slips and seems strong. The problem is that when you push the clutch pedal all the way down you can not engage the PTO in without it grinding. I have shut off the tractor and engaged the PTO as soon as it starts and it seems to work fine after it is engaged, but will not stop when the clutch is pushed in. My question is do any of you experts have any suggestions before I break the thing in half? Thanks to all who reply.

JC-jetro · Mar 6, 2008

rojo said:
I recently purchased a JD 970 and believe the PTO clutch might be out. The drive clutch seems to work fine, although it seems a little long on the clutch pedal. It never slips and seems strong. The problem is that when you push the clutch pedal all the way down you can not engage the PTO in without it grinding. I have shut off the tractor and engaged the PTO as soon as it starts and it seems to work fine after it is engaged, but will not stop when the clutch is pushed in. My question is do any of you experts have any suggestions before I break the thing in half? Thanks to all who reply.

I don't own 790 but I know it has live PTO (double clutch) in the bell housing. One clutch disk and it's pressure plate operates transmission input shaft and a second set operates PTO shaft. The PTO is mechanically coupled or decoupled by your PTO lever. The coupling of two shafts normally done with a sliding gear along with a one way clutch in newer vintage tractor like yours. I do not think you have a major issue. You need to adjust pto clutch. may need to refer to IT service manual ion how to do yours, as they may be slightly different from makes and models but the concept is the same. When you push the pedal all the way the clutch disk is not disengaged from pressure plate hence, rotation of pto shaft and grinding the pto shaft coupler as a result.. Roy Jackson is quite knowledgeable and does have a 790. Wait to see if he chimes in or send him a PM to ask.

JC,

ps. I'm curious if you meant 790 rather than 970, I just noticed it.

RoyJackson · Mar 6, 2008

Yeah, I do own a 790, but Rojo is asking about a 970 2 stage clutch.
I have a manual for all the Deere x70 and 790 tractors. I'm at work right now, but will look up the adjustment procedure tonight.

BTW, this manual is from Deere and is on CD-ROM. It's $48 (was when I got it, anyway) and is a very worthwhile investment if you intend to keep that 970 (fine tractor...wish I had one!)

rojo · Mar 8, 2008

Gentlemen, the tractor is a JD 970. I have a John Deere Technical manual and it shows how to adjust to clutch. There is only one adjustment and it does both the main clutch and the pto clutch (I think). I have not had time to do this yet and hope to get to it on Sunday. I was just wondering if anyone had seen this problem before because it doesn't seem as the main clutch really needs adjustment. But maybe a little adjustment will do alot. I will let you know. The CD-Rom you where talking about is the same as this tech. manual or no?

JC-jetro · Mar 8, 2008

rojo said:
Gentlemen, the tractor is a JD 970. I have a John Deere Technical manual and it shows how to adjust to clutch. There is only one adjustment and it does both the main clutch and the pto clutch (I think). I have not had time to do this yet and hope to get to it on Sunday. I was just wondering if anyone had seen this problem before because it doesn't seem as the main clutch really needs adjustment. But maybe a little adjustment will do alot. I will let you know. The CD-Rom you where talking about is the same as this tech. manual or no?

Rojo,

The procedure is the same with either 970 or 790. I have done the procedure for single clutch only but studied the dual clutch system also. There are two things to consider. One is the distance between the release fork and the spring loaded finger on the pressure plate . Basically enough distance is maintained between the release fork and fingers so they don't touch but close enough. The second is the spring adjustment between pto clutch disk and it's pressure plate. On 1700 with dual clutch yo can tighten or loosen the spring action. What I also would do is to mark all my adjustment nuts and what have you with a chalk, paint or soap stone to know the before condition.

good luck,
JC,

Keoke · Mar 8, 2008

Hi Rojo, there is a very good chance that the PTO clutch is stuck (rusted) to it's pressure plate. This is a common occurrence, especially on clutch disk's that utilize metallic linings. This condition usually occurs when tractor sits for a long time in humid or wet conditions. Some manufactures recommend blocking down clutch pedal when tractor is going to sit for a long while.
You can try breaking the disk loose by engaging the pto and then locking the out shaft from turning (lock drive shaft after shear bolt on rotary mower with pipe wrench, etc.) and then bumping the starter with ignition off. Have a helper hold clutch pedal fully down while you bump the starter. You will have to go directly to starter solenoid to do this since engaging pto will open starter circuit at safety switch and ignition will be off.
Keep in mind that this procedure will put some strain on starter drive gear so go easy.

lot's of luck,
keoke

rdln · Mar 8, 2008

I can say that while at my local dealer about a year ago, a used 1070 caught my eye, a fellow traded it in, it needed a clutch. I asked the dealer how to tell and he said that the pto will stop engaging b4 the trans stops.

RoyJackson · Mar 8, 2008

rojo said:
Gentlemen, the tractor is a JD 970. I have a John Deere Technical manual and it shows how to adjust to clutch. There is only one adjustment and it does both the main clutch and the pto clutch (I think). I have not had time to do this yet and hope to get to it on Sunday. I was just wondering if anyone had seen this problem before because it doesn't seem as the main clutch really needs adjustment. But maybe a little adjustment will do alot. I will let you know. The CD-Rom you where talking about is the same as this tech. manual or no?

Yep, it's the same...CD-ROM is cheaper, that's all.

I had a 670 (basically the same as the 790, but less power and smaller tires) that I had always thought had a single stage clutch. When I traded it off for my 790, the dealer told me it was actually a 2-stage that required adjustment. I don't know if it took splitting the tractor to do this, but they had it squared away within a week since they sold that machine in a week.

I've adjusted the clutch pedal free play, but never had to go any deeper. However, I'd talk to a dealer tech before I'd try breaking a frozen clutch loose. If it were a single stage clutch, I'd have no qualms about popping the clutch. But messing around with the PTO could do some serious damage to the PTO gearing or even worse if your helper doesn't hold that clutch all the way down.

Keoke · Mar 8, 2008

Roy, one would think that if the pto drive train is strong enough to snap a 1/2 inch shear bolt repeatably it should be able to handle what ever torque a starter motor can come up with.
Rojo, for added safety while trying to brake clutch plate loose you could put a shear bolt on the rotary mower that is half the size of the OEM bolt.

take care,
keoke

RoyJackson · Mar 8, 2008

Keoke said:
Roy, one would think that if the pto drive train is strong enough to snap a 1/2 inch shear bolt repeatably it should be able to handle what ever torque a starter motor can come up with.
Rojo, for added safety while trying to brake clutch plate loose you could put a shear bolt on the rotary mower that is half the size of the OEM bolt.

take care,
keoke

I'd be more leery of trying to hold that PTO from turning with a pipe wrench. I'm sure you didn't mean for someone to hold it...but that PTO puts out a lot of torque (as you know).
Guess I am a safety freak!