NH 1920 Two-speed PTO option: How can I tell if my tractor has this?

grcutter · Nov 30, 2022

I just acquired a 1997 NH 1920 which has a PTO grinding issue (which I will ask about in a later post).

The repair manual for the 1920 (page 319) states that some models have an optional two-speed PTO but the owner/operator's manual makes no mention of this.
How can I determine if my tractor has this optional two-speed PTO and how is it controlled?

Here is the text from the repair manual:

From figure 4, it looks like the Sliding Gear(2) would move in two directions with Neutral being in the middle.
My tractor appears to only two positions for the PTO level so maybe it does not have this option.

Thanks in advance!

Sincerely,
Dan

MTGreen · Nov 30, 2022

I would imagine that was not a common option as there are few 3pt implements designed for 1k RPM that will run on that small of a tractor. But from the mechanism diagram, your PTO lever that actuates that sliding gear would have to have three positions with the center neutral. Since you just told us there's only two positions I would make the assumption that you don't have the two speed option

Btown · Dec 4, 2022

The grinding issue is your clutch needs adjustment.

setxjeff · Dec 4, 2022

My International harvester 254 (25 hp) has a two speed Pto. You have to take a plate off at the Pto lever and flip it over so the pto lever will go the other way.

TractorTech · Dec 4, 2022

US 1920s did not have a two speed PTO. Those that have two speeds are 540 and 750 rpm. There is usually a lever on the side of the rear case that allows the sliding collar to shift from one to the other.
And, as Btown indicates, the clutch needs adjusting. Could be a double clutch, where the main transmission clutch is fine, but the PTO clutch needs adjusting via the rubber plug on the side of the clutch bell housing. Other posts explain procedure.

scootr · Dec 4, 2022

My now gone Terex 640 had the 2 speed PTO. It had a position lever marked 540 - N - 1080.
I used the 1080 for one mowing. It really made the BH sing but I worried the BH was not made for the high speed.

grcutter · Dec 5, 2022

Thanks everyone.
I'm now convinced that my PTO is single speed only.

I'll look up the procedure to adjust the PTO clutch through the hole with the rubber plug.
I'm concerned that it may be more than the clutch since there is a position of the PTO shaft with no grinding but all no spinning....
But I will try to remain optimistic.

TractorTech · Dec 5, 2022

grcutter said:
Thanks everyone.
I'm now convinced that my PTO is single speed only.

I'll look up the procedure to adjust the PTO clutch through the hole with the rubber plug.
I'm concerned that it may be more than the clutch since there is a position of the PTO shaft with no grinding but all no spinning....
But I will try to remain optimistic.

Just wondering. On the double clutch unit, when you depress the clutch half-way, you are disengaging the transmission clutch. When you depress the clutch all the way down, you are releasing the PTO clutch. Is that what you mean when you say, "there is a position of the PTO shaft with no grinding but all no spinning...."?

grcutter · Dec 5, 2022

TractorTech said:
Just wondering. On the double clutch unit, when you depress the clutch half-way, you are disengaging the transmission clutch. When you depress the clutch all the way down, you are releasing the PTO clutch. Is that what you mean when you say, "there is a position of the PTO shaft with no grinding but all no spinning...."?

My clutch appears to disconnect both the PTO and the main clutch at the same time with just about 25% of the pedal pushed in.

I realize that I may not have described the 'no grinding' situation very well so I will try again:
With the PTO lever engaged and the clutch fully out, I noticed that occasionally there is no PTO shaft grinding but also no PTO shaft rotation at the same time.
Under these conditions, I tried to rotate the PTO shaft back and forth a little bit by hand and found that there is a tiny range (maybe an angle of < 10 degrees) where it does not rotate even though it is engaged.
Beyond this small range, the shaft will 'catch' and start to rotate but with grinding.
The other thing that happens with the PTO grinding is that the PTO lever gets pushed back out of position and becomes disengaged all by itself.

I'm not sure what to think about the small range with no rotation.
I'm imagining a PTO shaft that is missing a few splines on a portion of the shaft but maybe there is some clutch related explanation for this.

What pushes the PTO lever back out? Is this also a bad clutch alignment symptom?

Tractor Tech · Dec 6, 2022

I still am not sure about the small erange of no movement you are talking about, but the lever popping out and the grinding makes some sense.
The detent spring on the PTO shift rail is not as strong or the gears that engage the PTO are really worn allowing it to slip out. This could also be why it grinds.
I don't remember, but I think the 1920 had a problem with the detent spring anyway, but could be thing of the 1910

grcutter · Dec 22, 2022

I'm spending my vacation day trying to solve this PTO grinding issue.
So far I have shortened the clutch rod. This did not help. With the clutch all the way in, I can engage the PTO level without the grinding. Then I can release the clutch about an inch before the grinding starts, pressing back in will stop the grinding. So it seems like the PTO clutch is moving back and forth as it should.
I moved on to trying to adjust the PTO clutch release bolts.
I removed the left arm that supports the front loader to reveal the rubber plug.
Opening the plug, I don't see any bolts to adjust. Do I need to rotate the clutch so that the bolts appear in the window?
Also, should there be any lubricant in this port? It is really dry in there. I poked my finger down to see if there was any fluid and just got some dried grease on the tip.

By the way, does the NH 1920 actually have this PTO adjustment? I could not find any mention of this rubber plug and hole in my NH 1920 service manual.
I had to go back to my Ford 1710 service manual (which covers 1210 through 2110) to find the description of this.

Here is the image from the Ford 1710 manual:

If I do have to rotate the clutch to find this bolt, how do I do that? Also, does this mean that there are 3 such bolts and I have to find all 3?

Below is the image from the NH1920 Service manual which makes reference to 3 PTO clutch release adjust bolts.

TractorTech · Dec 22, 2022

Yes, the 1920 double clutch has this adjustment and you would rotate it to find the bolt/lock nut. BUT, since you can stop the PTO with the clutch pedal all the way in and shift without grinding, it does not need an adjustment! It sounds as though everything is operating properly on the clutch.

Now, when you engage the clutch/let out the pedal for the PTO, the grinding starts. This tells me that the grinding might be a bearing or some other problem. Where is the grinding sound coming from? Bell housing, mid transmission or rear end? This is related only to the PTO?

I read your descriptions again and I thought about this more. Pretty sure the sliding collar for the PTO is what is causing the grinding. This would explain the shifter being pushed back. Question is, what came first, the stripped shaft or the lever not holding position causing the shaft/gear to strip? Stripped splines or gear teeth on the collar/shaft would fit your description. Not 100%, but sounds like it.

TractorTech · Dec 22, 2022

Here are some shots from the Service Manual on the PTO and rear end

grcutter · Dec 23, 2022

TractorTech said:
Yes, the 1920 double clutch has this adjustment and you would rotate it to find the bolt/lock nut. BUT, since you can stop the PTO with the clutch pedal all the way in and shift without grinding, it does not need an adjustment! It sounds as though everything is operating properly on the clutch.

Now, when you engage the clutch/let out the pedal for the PTO, the grinding starts. This tells me that the grinding might be a bearing or some other problem. Where is the grinding sound coming from? Bell housing, mid transmission or rear end? This is related only to the PTO?

I read your descriptions again and I thought about this more. Pretty sure the sliding collar for the PTO is what is causing the grinding. This would explain the shifter being pushed back. Question is, what came first, the stripped shaft or the lever not holding position causing the shaft/gear to strip? Stripped splines or gear teeth on the collar/shaft would fit your description. Not 100%, but sounds like it.

Having looked at the clutch plates, I agree with you: This is not a clutch plate adjustment issue, it is a problem with one or more gears in the rear.

One thing that was not clear from the repair manual, (but probably should have been obvious?) is whether the 1mm gap in the clutch plates is measured with the clutch fully in.
With the clutch fully out, the plates appear to be touching. When fully in, there was about a 1mm gap.

I was able to put a 14mm open end wrench on one of the bolts but could not move it. The flywheel started to move instead. There also seemed to be maybe enough room for 1/8th turn at the most. Something would be needed to hold the fly wheel from rotating at the same time.

For completeness, in case others go down this path, I'm including pictures of this bolt, hole, and plug.

grcutter · Dec 23, 2022

TractorTech said:
Here are some shots from the Service Manual on the PTO and rear end
View attachment 775855 View attachment 775856 View attachment 775857 View attachment 775859 View attachment 775860

If I interpret these service manual pages correct, then it appears to be a huge undertaking even to just view the gears. I'm under the impression that removing the hydraulic lift cover is not trivial.

TractorTech · Dec 23, 2022

If I remember right, you can remove the seat and sheet metal over the rear axle to access the small plate in front of the top cover.
Then, you should be able to access the PTO coupler for inspection.

It may be that the rollbar top half comes off, then the fenders/rear deck come off. Can’t remember for sure.

MTGreen · Dec 23, 2022

TractorTech said:
If I remember right, you can remove the seat and sheet metal over the rear axle to access the small plate in front of the top cover.
Then, you should be able to access the PTO coupler for inspection.

It may be that the rollbar top half comes off, then the fenders/rear deck come off. Can’t remember for sure.

On my 1720 you don't have to remove the rops/fenders to access this panel

grcutter · Dec 25, 2022

Happy Holidays Everyone!
Tomorrow, I will remove the seat and look for this small plate on the top of the lift cover (after temperatures get above freezing...).
But from looking at the parts diagram, I don't see any plate.
Am I misinterpreting this?

TractorTech · Dec 25, 2022

That is a picture of the top cover or rockshaft. The plate is forward of that on the rear axle housing

grcutter · Dec 26, 2022

I removed the small plate that is in front of the lift cover.
Looking inside, I don't think that I was able to see the PTO gears.
In general, everything appeared to be OK from this view point but I have never looked in here before.
I'm posting the pics in case some sees something that I missed.
I'm wondering if I can remove the round collar on the PTO and look in that way. Is that possible?