Ford NH 2120 chatter in 4wd

   / Ford NH 2120 chatter in 4wd #1  

Redz

Member
Joined
Feb 19, 2019
Messages
28
Tractor
Ford 1920
Hi ,

Recently Ford NH 2120 (mfg 1990) started this chattering noise whenever it’s put into 4wd . The noise seems to be coming from the front of the front transmission where the driveshaft to the front axle goes in.

At this point I’m clueless as to the cause but imagine it some sort of splined shaft that’s slipping.

Any suggestions on how to proceed. We have a service manual somewhere.

I’ve been asked by the farmers if it’s ok to use in 2wd mode , I’m not really sure.

Thanks!
 
   / Ford NH 2120 chatter in 4wd #2  
If the noise goes away without the front axle engaged it shouldn't cause any further harm to run it. I would say first place to start would be pulling the driveshaft to the front axle and check for play on the output shaft of the transmission. I would leave it out until fixed cause a lot of the parts are hard to get on those anymore.
 
   / Ford NH 2120 chatter in 4wd
  • Thread Starter
#3  
Thanks , that sounds good.

I had a look at the parts diagram and I’d guess that I’m going to find an issue in that small gear case that hangs off the lower side of the transmission case where the front driveshaft attaches. Probably there is a stripped gear or spline or broken woodruff key. The chatter noise and vibration seemed to come from there.
E0CF6111-E459-484F-85E4-B6C2E957A18D.jpeg
 
   / Ford NH 2120 chatter in 4wd #4  
I agree with claggstractors, pull the front driveshaft and inspect. It is common for the couplers and the splines to get damaged on theses tractors.
 
   / Ford NH 2120 chatter in 4wd
  • Thread Starter
#5  
We operated without the 4wd since it started making noise and have managed.

Today, we finally got around to opening up the fwd lower gearbox on the 2120. I drained the oil and removed the gearbox and had a close look at the gears and the spline shaft that sticks out of the gearbox and couples with the driveshaft. All the gears and splines look good without any wear, breaks or chips and no steel chips were found. The gears are tight and no play is evident so it seem the problem lies elsewhere in the fwd drivetrain.


Unfortunately, before starting the disassembly, we didn’t engage the 4wd and listen closely to identify from where the chatter noise is coming from.

Should we bolt it back together and listen for the chatter or should we remove the driveshaft and check the splines on the front axle end ? I imagine the chattering could be coming from anywhere along the fwd drivetrain.

Thanks !
 

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   / Ford NH 2120 chatter in 4wd
  • Thread Starter
#7  
We used a screwdriver and pried the driveshaft away from the front axle. Once off , it was clear that indeed it was the coupler that had gone bad , all the splines were chewed off from one side. A new coupler part is on order for $130. Thankfully the root cause was something simple and fairly easy to get to.

Thanks for your suggestions!
 

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   / Ford NH 2120 chatter in 4wd #8  
How are the splines of the shaft and pinion? When replacing the new coupler, clean the mating shaft and coat with a quality antiseize material.
Some even seal both ends of the coupler with silicone caulk to prevent any moisture from entering.
 
 
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