NP231 Front Output Shaft Bearings

[LBEXJ]

It seems I have always had a certain amount of front driveline vibes. They seem to be getting worse, especially after this last wheeling trip I've taken. While checking for cause, I've noticed some play in the front output shaft. More than likely the bearings are shot which is causing the vibration.

My question ... Is there much of a possiblity the output shaft is worn or has been damaged due to the bad bearings? Any input would be appreciated.

Les

 

[explorer]

Assuming that the yoke is tight on the frt. output shaft, the frt. brg. inner race gets clamped between the yoke and a shoulder on the frt. output. The brg. surface is not the shaft itself. The rr. brg. for the frt. output runs directly on the shaft. A very slight amount of play is normal. How much os there?

 

[8Mud]

I´m gonna have to do the same on my 242 soon, hoping it´s just the bearings. Did notice, there is some side play in my front driveshaft slip splines and also my pinion seal is seeping. Don´think the last guy who owned my 88 was big on greasing and maintenance. I think the play in the driveshaft slip splines, probably accelerated the front TC bearing wear. When I take the front driveshaft out, I´m gonna have a look at the Carden joint also, though it does seem OK.

 

[LBEXJ]

Assuming that the yoke is tight on the frt. output shaft, the frt. brg. inner race gets clamped between the yoke and a shoulder on the frt. output. The brg. surface is not the shaft itself. The rr. brg. for the frt. output runs directly on the shaft. A very slight amount of play is normal. How much os there?

It's kinda hard to give you a "measurement" of how much play there is, but there is enough I can hear a slight knock when the shaft is moved up and down.

Lets assume the yoke may not be tight (not checked it yet). Could there be play from the yoke not "clamping" the outer bearing in the shoulder on the housing? Could the movement be the knock I'm hearing? What is the torque spec on the yoke nut?

To give you an idea of the vibes I get ... none with the drive shaft unhooked from the front pinion at all speeds (i've only driven up to 75mph) ... none to very slight up to 55 mph with the front drive shaft attached to the front pinion, minor at 60 ... a definate "growl" at 65 on up.

Les

 

[LBEXJ]

I´m gonna have to do the same on my 242 soon, hoping it´s just the bearings. Did notice, there is some side play in my front driveshaft slip splines and also my pinion seal is seeping. Don´think the last guy who owned my 88 was big on greasing and maintenance. I think the play in the driveshaft slip splines, probably accelerated the front TC bearing wear. When I take the front driveshaft out, I´m gonna have a look at the Carden joint also, though it does seem OK.

I checked the splines on this shaft for some play ... none ... it's in good shape. Had the drive shaft and double cardon rebuilt last summer. But ... my front pinion seal began leaking after the long drive I just took (10 hours), but I had the drive shaft disconnected. Go figure :dunno: ... it's on the list to replace.

Les

 

[explorer]

If the yoke is loose, yes that sould be the source of the play. I don't remember the torque spec. off the top of my head, but its just clamping the inner race. An impact isn't going to cause any problems here. The slip spline on the shaft was my next suggestion, but you've covered that it sounds like. One thing with that, is the slip can be pretty loose without actually feeling it clunk around when you grab it. Just make sure visually it isn't rocking. If the pinion seal is leaking, there is the potential that the yoke there is loose. That could also be something to check. Again, that nut can be tightened without worry, if its a high pinion axle. The preload is set w/ shims.

 

[LBEXJ]

If the yoke is loose, yes that sould be the source of the play. I don't remember the torque spec. off the top of my head, but its just clamping the inner race. An impact isn't going to cause any problems here. The slip spline on the shaft was my next suggestion, but you've covered that it sounds like. One thing with that, is the slip can be pretty loose without actually feeling it clunk around when you grab it. Just make sure visually it isn't rocking. If the pinion seal is leaking, there is the potential that the yoke there is loose. That could also be something to check. Again, that nut can be tightened without worry, if its a high pinion axle. The preload is set w/ shims.

I'll check both yokes before replacing the pinion seal and tearing down the TC and replacing the bearings ... Thanks.

Les

 

[LBEXJ]

Explorer ... I owe you. The yoke was a bit loose on the output shaft. After tightening, the vibes are all but gone.

I really appreciate your input ... it sure saved me a lot of work.

Thank You ...

Les

 

[Ron Hyslop]

I just took apart an np207 out of my 86xj 4 banger because of vibrations. At 195,000 miles, everything inside looked like it was new. All I repaced was three shift for pads on the range fork for $4. However I did find the front drive shaft forward u-joint bad.