John Deere 990 4WD problem

[markabasinger]

My JD 990 tractor makes a clunking, binding type noise when in 4WD. It functions fine in 2WD mode. It still works in 4WD, but has the noise so I quit running it immediately. I am trying to remove the front
drive shaft to inspect where it enters the differential but my JD technical manual has no information about how to remove. I've attached a picture.

 

[markabasinger]

Didn't see my picture in the original post so attempting to repost.
<img src=https://www.yesterdaystractors.com/cvphotos/cvphoto136180.jpg

 

[wore out]

I don't think you want to be removing the pinion quill from the MFWD axle at this point (I noticed you've removed bolts), if the problem is that deep likely the axle will have to be removed from the tractor for repairs.

Does the driveshaft run ''true'', or possibly wobble?

There's a CV joint of sorts at each end of the driveshaft, I suspect it can be removed by pulling rearward on the front joint, collapsing the spring and allowing the CV joint to slide off of the pinion splines, or perhaps come apart.

If one or both joints DOES come apart, there's 6 steel balls in each to keep track of.

If there's nothing obviously wrong with the driveshaft, I'd drain the oil in the front axle and note if any metal filings or pieces come out.

 

[used red MN]

Hello Mark welcome to YT. I am an IH guy slow on the IH forum since those red ones never breakdown. I have no idea, but if you pull that cotter pin so the spring can slide back then will it let you slide the coupling or whatever you call it back on the splines and let it come out then? My SWAG, I think that thing is only John Deere by the name stickers.

 

[markabasinger]

Thanks for chiming in. I will attempt to slide the drive shaft back and get some clearance to drop it. I agree-JD in name only, it's a mutt made up of international parts I would guess. I have a red one also-Farmall 756. It's running right now but I've laid under it a few time also

 

[markabasinger]

Thanks Wore out-The drive shaft appears to run true. I will attempt to slide the joint on the splines but it seems hung up. It will only move about 1/8 of an inch. I thought that might be my problem. Perhaps the steel balls are worn?? Maybe not letting it slip fully into the splines in the differential?

 

[used red MN]

Are the front wheels off the ground or is there at least some slack in drive train? There may be some wear in the splines so it may need more play to move onto the section of splines that it normally does not ride on. May even need a little help from a hammer. Put a wood block up there to pound on so you do not mess anything up.

 

[markabasinger]

Good advice. Let me lift the front end off the ground and see if I can give them a nudge.

 

[markabasinger]

Lifted the front of the tractor off the ground a bit and the shaft came right out (along with the 6 ball bearings on each end. I found them easily but it appears the rear coupler on the shaft is badly worn causing the coupler to hop over the bearings under load. Will need to replace the coupler and the ball bearings. I will send some pics in a minute but thanks for helping me get this far.

 

[markabasinger]

(quoted from post at 16:32:56 09/19/22) Lifted the front of the tractor off the ground a bit and the shaft came right out (along with the 6 ball bearings on each end. I found them easily but it appears the rear coupler on the shaft is badly worn causing the coupler to hop over the bearings under load. Will need to replace the coupler and the ball bearings. I will send some pics in a minute but thanks for helping me get this far.

Picture of rear coupler wear