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Discussion Starter #1
Hello Ford / New Holland Tractor Forum members! I decided to sign up here for your Forum looks to be active still and I am in need of some information / help with my '98 2120 HSS.

I experienced the loss of forward and reverse in all gears and ranges. I got a copy of the service manual and supplement manuals. I performed the electrical checks for the HSS system and everything checked out OK. I did not perform the hydraulic pressure test, for the loader and 3-point work just fine. I did a lot of internet searching and everything I found pointed to either a switch, the HSS control module or the shuttle clutches themselves worn out. With finding nothing with the electrical checks, I figured it had to be the clutch packs.

I split the tractor down to the front transmission and removed the shuttle clutch assembly. When I disassembled it, I did not find the wear I was expecting. According to the service manual, the service limit of the shuttle clutch discs is 1.9mm thick. Mine are measuring out at 2.12mm thick.

Now I need to put the tractor back together so I can perform the other system tests I should have performed before I tore it apart. I plan to replace all the seals and gaskets, but I am on the fence for the clutch discs themselves. I am looking for what is the thickness of the replacement clutch disc vs. what mine are at? The nearest dealer to me is over an hour away and I have no working relationship with them. There was a dealer closer to me that I worked with but they closed-up about 10 years ago.

The other problem is these clutch sets: CNHi P/N: SBA320690098 is now discontinued, but I have located some at dealers several states away from me. Therefore, I am questioning whether I should spend the money on the replacements or just put my originals back in?

Any information, advice or insight from anyone would be greatly appreciated.
 

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Just personal opinion here, but If it were mine and I found that twenty plus year old plates are still within spec, I'd be looking elsewhere for a problem. They would need to be pretty cheap to justify throwing them away. Pay more attention to piston seals, sealing rings and related grooves, O rings etc, that might contribute to fluid/pressure loss during operation. Put your unit back together on the bench and if at all possible air check the clutch packs several times each to see how they react before assembling back into the tractor for actual system pressure checks.
 

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Discussion Starter #4
Thanks for the input Fedup. Yes, I did do air checks on the apply pistons prior to disassembly. The Forward clutch piston seemed to leak more than the reverse one, but not enough that I would think there would be loss of holding pressure on the clutch pack. When I got the pistons out of the bores, I am only finding slight scratches on the seal rings (metal rings).

I agree with your statement about not pitching 20+ year old plates when it does not seem to be the problem, but I have a friend that is a tractor mechanic and his advise was since the plates are 22 years old, I may have another 8 years at the most before the bonding in the friction material starts breaking-down and coming off the plates. But, if new plates are only 0.1 ~ 0.2 mm thicker than my 22 year old ones, I am leaning towards not replacing them at this time.
 

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As always, its your tractor, your money, and your choice. Again, I doubt the plates are any part of the problem. I would be looking for leakage as far back as I could get. From the points where the control valves send fluid into the first port if at all possible. Not just the clutch piston seals themselves. When using air for testing, remember to first put as much oil as you can into the ports. I use a squirt can or a squeeze bottle. I'm guessing you're either losing pressure somewhere, or the system just isn't building it.
 

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Discussion Starter #6
OK, I got the information I was looking for! Ran into a friend I've not seen in awhile and told him my issue. He tells me that his neighbor has been slowly replacing all his farm equipment with New Holland stuff. So we went and talked to his neighbor, who called his dealer and got them to contact CNHi to get the clutch disc thickness new. Turns out they are 2.3mm thick when new. So mine are only about half worn based on this. Now it's just the waiting game for the rest of the parts to show up and start reassembly so I can figure out what really is causing the problem.

Thanks again Fedup- I am planning on doing the trouble-shooting diagram in the manual to test the entire hydro-circuit for the HSS to make sure what I should have before I tore this thing apart.
 

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Discussion Starter #7
Got busy with stuff for the last month or so and forgot about this site, so I thought I would get around to an update:

After figuring out that my shuttle shift clutches were fine, I ordered the seal kit for the apply pistons. Even though I could not see any significant wear on the originals. When I got the new seals, I got out the mic's and did some checking old to new and I did find that the outer piston seals on both the forward and reverse pistons were 0.015mm thinner than the new ones. So I called that the problem and reassembled the front transmission with all new seals.

Got the rest of the tractor re-assembled, filled with fluid, fired up and everything works! I have forward and reverse in all gears once again. Also the engagement of the shuttle definitely feels tighter and less sloppy than even when I first got the tractor with 900. hrs on it.

So here it is, back to work on January 2nd, doing the chore it was purcahsed for
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