TJ Rubicon Front Pinion Yoke Movement

[derekmac]

When under my Jeep recently (actually a while ago, but forgot about it ), I noticed that the front Dana 44 yoke had a tiny bit of up/down play. You can't really see it move, but can feel it.

I removed the driveshaft, and when I rotate the pinion, it also goes in/out ever so slightly (VERY little movement). When it's either in or out, there's no up/down play, it feels solid.

Could this just be a case of the pinion nut not being tight enough, or bearings going? It doesn't leak, and when I had the front cover off not long ago, all the gears looked fine.

 

[Mike_H]

I would say that the nut is not tight enough...but I'm no expert.

 

[Rook]

Some rotational play is perfectly normal, but there should be no actual movement side-to-side. Only rotational movement.

So if you can grab the pinion and try to lift it up and down or side to side and all it does is rotate, then you are fine. But if it actually moves up-and-down or side-to-side, something's not right.

I don't know much about drivetrain myself, but I recently had some problems up front and talked with a lot of folks who do, including Tom Wood who passed this information to me.

 

[Rob5589]

There should be no up and down or in and out movement. Either the nut backed off, unlikely, or the pinion bearings are shot, likely.

 

[Jerry Bransford]

There should be no up and down or in and out movement. Either the nut backed off, unlikely, or the pinion bearings are shot, likely.

Exactly.

 

[derekmac]

I'll try tightening the nut first, and if that doesn't do anything, I'll tear into it. It's been like this since at least the summer (when I first noticed it), and it hasn't gotten any worse.

There's an inner and outer bearing on the pinion, correct? I'll also guess that the inner one needs to be pressed on? I'm planning on buying a shop press so I can change my rear axle bearings, and if one is needed for this job too, it'll help make it easier to justify to my wife that it'll pay for itself, lol.

For the bearings, are Timken's the ones to get? I need to order some stuff from RockAuto, so I might as well put these on the order too. What else will I need? New pinion nut, seal...

 

[Rob5589]

I'll try tightening the nut first, and if that doesn't do anything, I'll tear into it. It's been like this since at least the summer (when I first noticed it), and it hasn't gotten any worse.

There's an inner and outer bearing on the pinion, correct? I'll also guess that the inner one needs to be pressed on? I'm planning on buying a shop press so I can change my rear axle bearings, and if one is needed for this job too, it'll help make it easier to justify to my wife that it'll pay for itself, lol.

For the bearings, are Timken's the ones to get? I need to order some stuff from RockAuto, so I might as well put these on the order too. What else will I need? New pinion nut, seal...

Timken or Koyo, your choice. Both are good, have used both with great success.

 

[Jerry Bransford]

Yes there's an inner & outer bearing on the pinion shaft and Timken would be a good choice. You can try tightening the pinion nut, I'd go 165-185 ft-lbs. but my bet is it won't tightening indicating you've got a bad pinion bearing.

With new bearings you're going to need to re-shim it which will require a pinion depth indicator and inch-lbs. beam indicator so you can set the pinion bearing preload. And installing new bearings even when shimmed to give the correct preload may cause the pattern on the gears to move which is not good since the R&P gears are work-hardened at the points they've been touching for years now.

Then you will have to contend with the Rubicon's locker indicator sensor which is in the way of the carrier being replaced without damaging it or the locker actuator. This is especially tricky with the front Dana 44 vs. the rear Dana 44 axle.

I guess I'm saying that you may be opening a can of worms with your plans to replace your pinion bearings. It's not all that straight forward, I've been part of that process several times the past two months.

 

[Mike_H]

So, curious about changing pinion bearings...Do you have to go through gear set-up again, or are the bearings close enough to be able to switch them with no ill effects?

Edit...Nevermind. Jerry answered it above. He and I were posting at the same time!

 

[derekmac]

Thanks for all that info Jerry.

This definitely sounds much more complicated than I had imagined it being. I'm always up for a challenge, but I really don't want to risk doing any damage, especially with how much it would cost for a complete rebuild if something let go because of the work I did.

Looking at options, can I remove the yoke and inspect the outer bearing, and just replace that (and the seal) if it appears bad, or could that screw up the internals too? Or is it usually the inner bearing that goes, or both?

Like I said, it's very minimal play and hasn't gotten any worse since I noticed it in July. The Jeep is driven around 6,000 miles a year, with very short highway trips. I don't want to damage it, but I can't afford to have a shop do this work right now.

 

[Jerry Bransford]

The outer bearing is inside the housing so it can't be removed or inspected without removing the carrier and pinion gear.

 

[Rob5589]

The likelihood of any significant change to the depth with new bearings is pretty slim. If it did, it would be so slight it would not cause any issue running it as is. That said, if the pinion is loose enough, it can contact the carrier and do damage to it and/or the pinion gear itself. If the pinion was tight, you could run a pattern before disassembly and use it as a baseline for the new bearings.

 

[Jerry Bransford]

The likelihood of any significant change to the depth with new bearings is pretty slim. If it did, it would be so slight it would not cause any issue running it as is. That said, if the pinion is loose enough, it can contact the carrier and do damage to it and/or the pinion gear itself. If the pinion was tight, you could run a pattern before disassembly and use it as a baseline for the new bearings.

So you're saying you'd keep the pinion shims the same after installing different pinion bearings? And if the pinion was "tight" after doing so he'd know how to shim it to correct the preload without it also changing the pattern? I don't think so.

 

[Rob5589]

So you're saying you'd keep the pinion shims the same after installing different pinion bearings? And if the pinion was "tight" after doing so he'd know how to shim it to correct the preload without it also changing the pattern? I don't think so.

Not at all. What I said was, new bearings alone won't necessarily change the pinion depth any significant amount, if any at all. If the pinion wasn't loose, he could run a pattern prior to disassembly to see where it is at so as to keep it the same depth. A used R&P shouldn't have the depth changed much at all since it has been run/broke-in at that specific depth. Pre-load isn't changing the pattern and has to be done with new or used bearings. The pinion being loose changes everything, however, depending on if any damage was done or any abnormal gear wear has occurred. I have done bunches of bearing only installs and it was rare to have to make any significant changes to depth.