# John Deere 4320 Compact Front Wheel Assist Issue



## Twospeed (9 mo ago)

I have a John Deere 4320 Compact with front wheel assist. It runs fine when in two wheel drive but recently start making a noise when I pulled up the lever to engage the front wheels. Now its making a grinding noise when I engage and is not really engaging the front wheels. Not good. It sounds like it is right under the seat where that lever where you engage the front wheels attaches to the side of the transmission. Anyone had any experience with this?


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## BigT (Sep 15, 2014)

Hello Twospeed, 

You might consider pulling the front drive shaft to confirm if the problem is in your transmission or related to the front axle.


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## thedukes (Jan 9, 2022)

Some of the small jd's have sheared the roll pin that holds the shift lever to the shift shaft.
This May be visible on the outside of trans.
Others have a similar issue....unfortunately its on the Inside of trans case.

Hopefully yours is a simple fix.


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## Twospeed (9 mo ago)

BigT said:


> Hello Twospeed,
> 
> You might consider pulling the front drive shaft to confirm if the problem is in your transmission or related to the front axle.


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## Twospeed (9 mo ago)

I actually thought about that to try and isolate the issue. However, on a quick glance underneath, it was not obvious how you take that shaft out. I expected to find a universal joint under there that I could take apart but on both ends the shaft just slides up on a spline shaft as best I can tell. Any experience or ideas on how you can get that shaft from under there?


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## Twospeed (9 mo ago)

thedukes said:


> Some of the small jd's have sheared the roll pin that holds the shift lever to the shift shaft.
> This May be visible on the outside of trans.
> Others have a similar issue....unfortunately its on the Inside of trans case.
> 
> Hopefully yours is a simple fix.


So I assume you have to break it in half if its on the inside correct?


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## Twospeed (9 mo ago)

BigT said:


> Hello Twospeed,
> 
> You might consider pulling the front drive shaft to confirm if the problem is in your transmission or related to the front axle.


I actually thought about that to try and isolate the issue. However, on a quick glance underneath, it was not obvious how you take that shaft out. I expected to find a universal joint under there that I could take apart but on both ends the shaft just slides up on a spline shaft as best I can tell. Any experience or ideas on how you can get that shaft from under there?


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## thedukes (Jan 9, 2022)

Look at your shifter b4 you go crazy on the driveline .
Its a pita
Typical JD driveline....out at yoke you will clean and then find a C clip of sorts.
Figure out how to pry that off/forwards away from u joint.
Under clip will be a Roll pin that needs driven out.
Going to have to repeat on the other end
Then slide one way or the other till one end drops

Sound like fun yet

Go to JDparts.com
look up your model #
There are lots of pics and parts diagrams to show exactly how yours is put together
The above description is "typical" of the newer assembliy's

You description of sound is like its not going in to gear.

Jack up 1 front wheel
Motor OFF
Shift to 4x4
will wheel turn...?
Whats the noise if it does?
& where is it coming from?
Report back


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## Twospeed (9 mo ago)

thedukes said:


> Look at your shifter b4 you go crazy on the driveline .
> Its a pita
> Typical JD driveline....out at yoke you will clean and then find a C clip of sorts.
> Figure out how to pry that off/forwards away from u joint.
> ...


Ok thanks for your help. That parts website was helpful. I will report back next week.


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## Twospeed (9 mo ago)

Twospeed said:


> Ok thanks for your help. That parts website was helpful. I will report back next week.





thedukes said:


> Look at your shifter b4 you go crazy on the driveline .
> Its a pita
> Typical JD driveline....out at yoke you will clean and then find a C clip of sorts.
> Figure out how to pry that off/forwards away from u joint.
> ...


I was able to do some more trouble shooting this morning. What I found with my drive line shaft was there is a plastic shield over the shaft itself to keep things from wrapping around it. I had to loosen the house clamp so I could slid that back and get to the coupling that you described. I did not encounter any type of c clamp. I simply knocked out the pin on the coupling, slid the coupling back and then pulled the shaft off the other end. I only had to knock out the pin on one end. I just give you that info for future reference and included a picture as well.

Here is what I have learned starting with the output shaft on the front of the transmission. If I leave the lever for the 4 wheel drive not engaged, I can spin the spline shaft on the front of the transmission with ease. If I then engage the lever, I can spin that same shaft just slightly and then it locks in, as I would expect if functioning properly.

Prior to doing this, I had jacked up the front and spun the front wheels by hand. I could hear that noise especially when I went from a stopped position to a rapid spin of the wheels. However, that sound was traveling down that drive line so it was still difficult to determine which end the noise is coming from.

While still having the front wheels jacked up, I put a pair of grip pliers on the spindle coming out of the front axle. I just took my hand and spun the front tire. The pliers and spindle would initially turn until the pliers got up to the oil pan (a point of resistance) and then the spindle would stop and I can continue turning the front wheels. I tried it both ways and the same thing both ways. I would assume that since that appears just to be a differential, that is not suppose to happen and hence I have isolated the issue to the front axle. 

If you agree with that what is next? Do you have any experience with that front axle? I read somewhere on line (and not sure that it was a 4320) of someone who had a front axle problem and they said you cannot get parts and you have to buy the whole thing. That seems a bit ridiculous but who knows.

Thanks for you guidance on getting that shaft out. That was invaluable.


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## thedukes (Jan 9, 2022)

I'd jack up the other front wheel.
Put that first one back on the ground.........easiest way to hold it.

Repeat your vise grip on the pinion....See if you can tell if noise is from right or left side.

Then rip into it.....Might find something on you tube or head over to the Greetractortalk site if no one here has a technical manual for your model.

Your issue is likely.......the gears in one knuckle or the other.

Hopefully Nothing in the Actual differential as that gets exspensive quick.

I've chipped a gear in one knuckle once and it was relatively painless pricewise...this was on a 955

They look similar to the spider gears in the Diff but are a bit different of course.


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## ovrszd (12 mo ago)

Thedukes is giving good information.

Bear with me, I'm old.... So with the pinion shaft on the front axle held so it can't spin, one tire on the ground, other tire in the air, you can spin the airborne tire?


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## Twospeed (9 mo ago)

thedukes said:


> I'd jack up the other front wheel.
> Put that first one back on the ground.........easiest way to hold it.
> 
> Repeat your vise grip on the pinion....See if you can tell if noise is from right or left side.
> ...





ovrszd said:


> Thedukes is giving good information.
> 
> Bear with me, I'm old.... So with the pinion shaft on the front axle held so it can't spin, one tire on the ground, other tire in the air, you can spin the airborne tire?


I did some more investigating. I put the drive line back in and then I jacked up and blocked the rear of the tractor off the ground. I think took the loader and lifted the fronts wheels off the ground. I got my wife to get on the tractor and engage the tractor while I got under so I could watch the driveline shaft. I was getting that chatter that I had heard before. I noticed after more observation that the driveline had some movement between the two differentials and then I noticed if i pushed the shaft toward the front differential the chatter stopped and the front wheels moved. Upon further investigation, I discovered that the inside of the coupling that fit on the pinion shaft coming out of the front is badly worn and slipping. I included picture. The first picture is what it looks like on one side and what it should look like and the other picture is the other side. I am pretty sure this is the issue.

Interestingly enough, when I was farming full time back in the 80's we had a John Deere
6620 Combine with pretty much the same set up. The shafts were bigger but came out of the side of the transmission and went over to the drive axles. It had these same type of couplings. One fall when it was really wet and we were getting stuck alot, we ripped one of these couplings out. 

I will go to John Deere in the morning. Pretty sure they will have to order it but fingers crossed this solves my issue. I will report back.


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## thedukes (Jan 9, 2022)

I agree that looks bad .

Doesn't explain this part though;
""While still having the front wheels jacked up, I put a pair of grip pliers on the spindle coming out of the front axle. I just took my hand and spun the front tire. The pliers and spindle would initially turn until the pliers got up to the oil pan (a point of resistance) and then the spindle would stop and I can continue turning the front wheels. I tried it both ways and the same thing both ways. I would assume that since that appears just to be a differential, that is not suppose to happen and hence I have isolated the issue to the front axle. ""

You must of had BOTH FRONT wheels in the air????

This is why I noted only do one....... Get a coupler.....Hopefully its 50$ or less..curious.

You may have stumbled in to an easy fix here.

Look in the area of the pin that holds coupler......The "Newer" drivelines have a circular clip that is centered over both ends of pin so it can't wiggle out.
If its not shown on the JD.com parts page for your unit ,then disregard.
Your probly "supposed" to use a new pin each time but if its a good snug fit it may be fine.
I'd get a pair of new ones since you likely need to order this coupler anyway.

Dan


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## ovrszd (12 mo ago)

Yahtzee. You found your problem.

To test the front diff you need one tire on the ground.


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## Twospeed (9 mo ago)

When I went back and tested with one wheel on the ground, the test I did with the grip pliers did not work. That is when I decided to put the drive line shaft back in. It was when I was doing that, I noticed this potential coupling issue. I did get a new coupling installed and that solved the issue. Boy was that a nice resolution. Thanks for all of your input. I do appreciate it.


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## pogobill (Jan 31, 2012)

Thanks for the follow up! It sure is nice to get the whole issue from start to resolve!


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## ovrszd (12 mo ago)

Thanks for the report!!! Was hoping it was something "simple".

I call this the KISS principle. Keep It Simple Stupid. Start with the simple and work your way up from there. Over the years I've learned this principle the hard way. Several times.


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