Grinding gears

woodlot · May 5, 2005

I've been doing some loader work with my tractor. Its a 1920 with the 12x12 sss trans. I'm doing all work at approx 2,000 rpm. Occationally I hear the dreaded sound of grinding gears (not real bad but a little grind) when putting it into forward or reverse. I'm trying to figure out why this is happening, if something is wrong or if I'm doing something stupid. I have the clutch fully depresed when shifiting. This does not happen all the time, in fact I'd say only 1 out of every 20 shift changes. I think I have determined that there is one serieno when it happens consistantly. Its when I'm changing directions (fwd to rev or vise versa) and I think I've caught gear but I'm acctually in neutral.....I let off the clutch thinking I'm going to move but I don't.....I then press in the clutch and shift into gear....this is when the grind occurs. However, if I'm changing directions and don't accidently put it in neutral I very rarely get a grind.

Can anyone help me out?

djradz · May 5, 2005

It's been several years since I had my 1720, but I seem to recall a similar situation, doing exactly as you've described. I too frequently went from forward to reverse, heck that's the beauty of the SS tranny, right, and then in the rare case when I slipped and didn't get it in, and then did, it would grind. Only thing I could figure was that I'd somehow gotten something free-wheeling/spinning, that normally wouldn't have, and it takes a minute to stop. You might try waiting a few seconds next time if you've messed up, before engaging, and see if this makes a difference. Never did see any damage however from operating this way.

tawilson · May 5, 2005

I've got a 2120 with the shuttle. Why are you using the clutch to shift between forward and reverse? I just flip the lever. If I'm moving, I'll just flip in in neutral to shift between gears. But it doesn't sound like you have a problem to me. Gring happens sometimes.

djradz · May 6, 2005

SS works like a stick shift, manual transmission automobile. You wouldn't shift that without clutching, or would you? /forums/images/graemlins/shocked.gif Don't think I ever shifted without pushing in the clutch, even standing still. Just a good habit I guess.

have_blue · May 8, 2005

Kidding, right? /forums/images/graemlins/shocked.gif

JerryG · May 8, 2005

Woodlot,
Are you letting the rpm go down before you try to put the shifter back into gear or are you maintaining the 2000 rpm the whole time?

You wouldn't shift that without clutching, or would you? Don't think I ever shifted without pushing in the clutch, even standing still. 
If you don't use the clutch on a shuttle you can very easily damage the transmission. Now, If it was a power shuttle you wouldn't need to clutch between forward and back.

tawilson · May 8, 2005

I thought the tractors we are talking about only had one type of shuttle, no clutch needed for forward/reverse. I'm talking the 17,19 and 2120. I could very well be wrong.

woodlot · May 9, 2005

I maintain 2000 rpm the whole time.

JerryG · May 9, 2005

ex. question :

If you have a standard transmission car or truck, would you keep the accelerator to the floor when you shift?
2000 rpm on a tractor would be like 5000 on a car or truck.

Let the rpm drop and then try shifting.

woodlot · May 9, 2005

I can't see going down to 500-750 rpm every time I change direction, I'm doing it about a hundred times. The loader work I'm doing is in a small area and frequent shift changes are needed.

woodlot · May 9, 2005

HaveBlue - I'm sorry but I don't know what you mean by your comment "kidding right." Please explain.

BGL990 · May 9, 2005

I can't see going down to 500-750 rpm every time I change direction, I'm doing it about a hundred times. The loader work I'm doing is in a small area and frequent shift changes are needed. 

Do you have a foot throttle? With my 990 being a plain old collar shift gear machine, I very rarely use the hand throttle to set and hold a particular rpm. I'm on and off the foot throttle all the time. Dropping rpm to shift just requires lifting your foot a bit. Using the foot throttle is also a good way to vary your speed more than is possible by just using different gears and a constant engine speed. Pretend it's a poor man's hydro ... /forums/images/graemlins/tongue.gif

Soundguy · May 9, 2005

( can't see going down to 500-750 rpm every time I change direction )

That's too low.. 1000rpm is about as low as I let my diesel tractor run, once it has been started and warmed..

Soundguy

tawilson · May 9, 2005

I think he was talking to djradz about the shuttle shift being like a manual transmission and having to clutch. There may be different types of shuttle shifts out there, but mine stays at operating rpm all the time and I just flip the lever back and forth. That's the beauty of them. My dealer told me to run it this way. JerryG, are you sure about what you're talking about, concerning the NH shuttle shift. I see a MF avatar up there. My dealer actually told me I could go down the road full bore and shift and it would just gradually slow down and then reverse. I haven't tried it yet. Prolly won't.

djradz · May 10, 2005

OK, when in doubt, consult the manual. The 2120 has a hydro, syncro shuttle, so I can't comment on it here, however, direct from the manual for the 1720 and 1920, I quote: "The 12 x 12 Synchromesh Transmission operates through the use of a clutch pedal, a shuttle shift lever and a range selector." Also, "The shuttle lever is used to travel forward or rearward. Depress the clutch pedal and pull the shuttle lever upward and push forward for travel forward, pull rearward for travel rearward. Always depress the clutch pedal fully before changing the shuttle lever position. Any of the main gear ratios may be selected with the tractor moving or stationary provided the clutch pedal is depressed." And lastly for those interested in changing ranges, "The range selector has 4 positions to select the required transmission range. Always depress the clutch pedal fully and bring the tractor to a complete stop before moving the range selector lever. Do not attempt to change gears (ranges) while the tractor is in motion."

I always operated my 1720 as the manual stated and never had any problems. I would think to do otherwise means grinding gears or forcing the gears to mesh while turning under load - not a good thing. So, to recap, change from forward to reverse or through rears 1 thru 4 - simply press the clutch and shift. Change ranges - press the clutch, bring the tractor to a stop (or nearly so) and change range.

djradz · May 10, 2005

Jerry, I recall several times when mowing, with the rpms at 2500 or so, simply pushing in the clutch, (halfway on the two-stage clutch) slowing the motion of the tractor down, and then ****ing to reverse to back into some location I couldn't otherwise hit going forward. I don't think I ever slowed the rpms in these cases and yet it shifted just fine. I always figured the syncro, in combination with the clutch, took care of this. No grinding, nothing unusual. I just checked the manual and couldn't find anything regarding this. If I was shifting the PTO in or out, I always did slow the rpms, in addition to using the clutch, but I don't think that was necessary.

tawilson · May 12, 2005

Here's a quote from my 2120 manual.
"The shuttle shift lever is used to travel forward or rearward. Without depressing the clutch pedal, it is possible to pull or push the shuttle shift lever. Pull the shuttle shift lever upward and push forward for travel forward, pull rearward for travel rearward." Guess there are different shuttle shifts. I sure do like mine.

djradz · May 13, 2005

I think you've hit upon the difference between what Ford/NH called the HSS - Hydraulic Shuttle Shift and the standard SS. The hydraulic must work a little like a hydrostatic transmission or have some sort of hydraulic pump that changes the direction of flow or something. I think the 2120 was the only model to have this feature and the rest used the standard shuttle which requires the use of the clutch. Sounds like a nice feature on the 2120, kind of like the electric-actuated range selector (turtle/rabbit switch) many of us have on the class III boomers. Cool!

NHeuro · Jan 12, 2006

I know this is an old post, so don't be angry /forums/images/graemlins/smile.gif

Shifting at 2000 rpm? isn't this quite high?
When i am mowing i put my rpm at 1500 rpm or 1800 rpm and give more throttle with my foot.
So when i shift i do it on "low" rpm this is much better for the clucth wear i think.