I'm still working on the same rear axle as seen in this thread: https://dodgeforum.com/forum/2nd-gen...questions.html and this thread: https://dodgeforum.com/forum/2nd-gen...questions.html

While under there I noticed fluid and gunk around the front and on the underside of the rear differential. So - in the words of @joetruckster , "while I'm at it" I decided to replace the pinion seal.

That's when I realized that I had misread/misheard/misunderstood what it would take to get to the pinion seal and then put it all back together.

I have none of the following:

1. Torque wrench for low inch-pounds
2. Torque wrench for in the 200s of foot-pounds
3. Impact wrench
4. 1-1/4" socket

So I've ordered #1, I intend to get a (hopefully inexpensive, but could be cheap) electric #3, and a set of impact sockets that will include #4.

My intent is to get a loaner #2 from one of the nearby national auto parts stores.

So while waiting to get those tools, I have two questions. But the answer to the first might affect the second, so I'll only throw out one right now:

QUESTION #1
When about to unbolt the drive shaft from the flange I noticed some play when spinning either the drive shaft or the flange. The wiggle was NOT in the u-joint - it seems to be inside the back of the differential where the pinion gear connects with whatever it connects with.

A few things to note:
- Both axle shafts are still out
- The center pin that helps hold the axle shafts into the differential is out
- Transmission is in Park

I've attached a couple of videos showing the play/wiggle.

Is that normal?
If not, what do I need to do?

 

I looked at video #2. What I saw was normal expected backlash.

 

You will have some movement. I agree that it looks normal.

 

Thanks y'all.

I have now thought of a 3rd question, but for the moment will only ask my second:

QUESTION #2
The service manual (which I downloaded from links here on DoFo) states under PINION SEAL for the 9 1/4 rear axle (emphasis in the original):
I'm not trying to "cheap out" and will do whatever is best. However, I don't want to spend money unnecessarily.

Do I need to get a new nut if replacing only the pinion seal?

 

I would, yeah. The idea is they're a mechanical lock of some nature and one-time use. You REALLY don't want it backing off. If I were in a remote area or something I might use copious LocTite and try to stake it, but that's not advisable

If you intend to replace the crush sleeve (I would) have fun getting that sucker to crush. You want a quality 1/2" or 3/4" breaker bar and a cheater pipe.

DO leave the carrier removed. The only way you can get an accurate reading of pinion bearing preload is without the drag of the carrier or axleshafts.

 

Very good to know - thanks!


Well, I was going to wait a bit to pose my third question, but your comments are a good segue way to it and also bring up yet another question:

BACKGROUND FOR QUESTIONS
I was originally thinking "while I'm at it" to replace all the differential bearings. However, along with acquiring the tools I listed in my first post, I already acquired others to do this job (which tools I hope will get future use): a bearing & seal driver set, and a multi-type puller set with a 5-lb slide hammer. So with all I've already purchased, I didn't really see myself also forking out dough for tools which I think are more expensive and which I am less likely to use in the future:

1. a bearing separator
2. a press
3. a clamping dial indicator

(I assume I could use those when working on the front differential; and my wife has a 4WD 2007 FJ Cruiser, so I assume I could use them on those two differentials as well. However, I'm still not sure I can justify the monetary outlay for the first two items.)

QUESTION #3
The current state: the axle shafts are out, but the carrier is still in.

As I understand it, if I remove the carrier, when I reinstall I will have to check/set the backlash, hence the need for tool #3. Is this correct?

QUESTION #4
Here is what is in the service manual under PINION SEAL:
The carrier is not suggested to be removed, nor the axle shafts, nor anything else on the pinion; and as I understand it, the crush sleeve is between the outer and inner pinion bearings.

It immediately then goes to (emphasis in the original):
So it seems there is an "official" process for replacing the pinion seal without replacing the crush sleeve.

What would y'all recommend:
- Just replacing the pinion seal as outlined in the service manual (thus foregoing the need to buy more tools)?
- Pulling carrier and pinion, and replacing only the crush sleeve, outer pinion bearings and pinion seal (thus hopefully only having to purchase a clamping dial indicator)?
- Pulling it all and replacing all of the above plus inner pinion and side differential bearings (for which I would need to buy the separator and press)?

 

You may be able to rent the more esoteric tools from your local parts store, if not, harbor freight has them pretty cheap. If I did it for a living, (not anymore) I would spend more money, on higher quality tools, but, for 'occasional use', they will do.

You could also probably just use gear marking compound (which you will need anyway...) to set the pattern. There are some good pics on the net that show what a proper pattern looks like. (also in the service manual, I do believe.)

As for 'should you replace them'.... If they weren't making any noise, I would just leave 'em in there, and just change the seal.

 

Yeah.....I'd probably leave pinion bearings alone unless they were noisy.

You do NOT need to reset anything or worry about backlash if you pull the carrier, just put everything back as it came out. I don't recall if the 9.25 carrier shims are under the bearings or outside of them? I should know this! It doesn't matter -- if they're outside just keep left on left and right on right.

DO mark the carrier bearing caps and put them back EXACTLY as they came out...both L/R and top/bottom. I reco stamping them with a matching stamp somewhere in the pig. Can be as simple as 2 dots left, 3 dots right. Or WHATEVER

Even if you opt to replace pinion bearings you don't really need to worry about the pattern, but it is BEST PRACTICE to run a pattern after new bearings are installed, just to be sure nothing atrocious is going on....but if it's anywhere near spec you just button it up and run it 'cause there's little you can do.

While the carrier is out and the pinion nut is off and the seal is removed you can drop the pinion out and feel both races. They should be silky smooth. Any divots or waves, then NOW is the time to replace. I bet a 4x4 or hot rod shop would pull and press bearings for you for under $50, maybe under $25

If you think the FSM says to leave the carrier in, ok. I personally would NEVER trust a pinion bearing preload reading with that additional drag. I've heard others claim you can just add X to account for the carrier, which to me is INSANITY -- there's just too many variables: how much gear oil is left in the carrier bearings? How is the condition of the carrier bearings? How tightly is the carrier wedged in there for carrier bearing preload (should be tight!)? Does gear ratio and even backlash affect inch lbs of effort to rotate?

 

Also, I see what the FSM is saying about just trying to match preloads by getting a reading beforehand. It reads to me like a "meh, probably" effort at time saving.

However plenty of places do it this way to save time, and I guess it works

 

The idea is, measure the torque before disassembly, then measure it again when you put it back together, but, just a hair bit tighter, keeps bearing preload consistent, so the bears aren't too loose. Torquing that nut down to truly stupid numbers ain't easy though.