Front Left Differential Seal and Adjuster Confusing Issue

[Einst-Hawk]

Hello everyone,

I have read many posts on here and the OS concerning the front drivers differential seal and bearing (adjuster). But I have yet to find anything posted asking the how and why (if you will) of putting the seal and adjuster back in the differential. I'll explain in a minute.

To start, I have a 2004 TB EXT LT 4x4 4.2L. I was doing a fluid change on pretty much everything. When I drained the front diff., there was only a drip or two that came out. I was surprised and hoped that I did not have a leak because there was no evidence of a leak anywhere around it. No fresh or old oil splatters. So I filled it up with Amsoil 75w 90. I then drained and replaced the fluid in the rear diff. All's well there. So coming back to the front, I saw a pretty dramatic leak on the front diff. I'd say a good 1/8 cup in about four hours.

So. I tore the whole front left apart. When I got the axle off, the seal and the adjuster behind it stayed on the shaft. Went to the dealership (I learned on here these are dealer parts only) to get the seal and adjuster. Bought the seal there. They did not have the adjuster in stock. I got the part no. and ordered it online. I also ordered a new half-shaft.
Part numbers were:
Seal: 1925-7296
Adjuster: 2605-4695


I compared the new seal and adjuster to my old ones. They are identical in size and shape as far as i can tell. Now here's my problem, since the old seal and adjuster came out and stayed on the shaft, I don't exactly know how to put it back in correctly.
There are threads on the outer rim of the adjuster and there are threads on the inner diff. housing, so one would think that the adjuster screws into the housing. But this is not the case. There is a couple mm's of play between the adjuster and the housing. I then put the old adjuster in to see if it screwed in. Nope. Although, the threads on it were very worn down. It also had play between the housing.

Also, on the old seal all the tabs were bent in and flat against the seal. Ok I thought. The tabs on the new seal will fit into the tabs on the adjuster. This isn't the case either. There are 14 tabs on the seal and 12 indentations on the adjuster. No matter how you spin the seal on the adjuster, no tabs ever match up and (seat) into the adjuster. WTF.

So here are my questions.

Does the adjuster just [float] behind the seal and the inner bearing? If so, what the hell are the threads for?

If none of the tabs on the seal match the indentations on the adjuster, do they just get smashed down flat and look like the old seal? If so, what the hell are the tabs and indentations for?

I don't want to put it back together and hope for the best. I want to know that I'm doing it right.

Any thoughts?

 

[The_Roadie]

Welcome! Glad you made it here out of the clutches of the OS.

1) The adjuster threads pretty much HAVE to engage to set the bearing preload. That's a meticulous process you only want to do during a differential build. SO the shop manual warns against moving the adjuster at all if you're just changing the seal. I can't explain at all why your threads don't engage even on your original adjuster. Unless you have diff housing damage, and that would be a really bad thing. Let's see if anybody who's done this before will chime in. I've done the seal only.

2) The secret trick to the tabs and slots is that the adjuster isn't supposed to be moved, and you might install the seal at any random angle. So they designed it so when you bang in the seal, all the tabs except two will be crushed back by the adjuster, but two of them will stick down just a bit and engage slots in the adjuster and keep it from rotating. The 12->14 difference is to make sure SOME pair of tabs will line up closely enough with SOME pair of slots somewhere around the circumference.

What I'm guessing is the seal failed, drooled out the fluid, the bearing adjuster stuck to the half-shaft, and rotated with the shaft in the direction that unscrewed the adjuster. It bashed around enough to damage the threads and I think you need a new diff housing now.

 

[v7guy]

The threads on that adjuster are suppose to thread into the diff housing, I have a spare diff sitting in the garage with the seal removed and the adjuster that preloads the bearing doesn't wiggle around and it's not possible to turn it by hand. I suspect Roadies assessment is accurate.

As Roadie mentioned the tabs on that seal are just there to keep the seal from rotating. You drive in the seal, the fingers grab a groove or two and the seal doesn't rotate with the axle because of it.

 

[Einst-Hawk]

Thank you Roadie and v7guy for responding.

The bad news roadie gave me is probably right. I will need a new housing. But this is an area beyond anything I have done before. I have changed out transmissions and replaced head gaskets in the past, but I have never dove into the intricacies of tearing a drivetrain completely apart.

Strange thing is, I had switched it into AWD and 4Hi and drove around for about 30 min. before I started changing the fluids. I wanted to get everything warmed up so it would flow out better. As far as I can tell, 4WD worked just fine. the steering became stiffer and I could hear the grrr sound when making tight turns. I do not really know about how 4WD works on my TB. Do the Two half shafts work independently or are they locked together when in 4WD? Maybe I only have 3WD. lol

Well I do need to get my TB back together. My daughter wants her car back. I'm going to go out to the garage now and see what the hell to do. I'm thinking if I can't get the adjuster to somehow screw in, I might just have to put it all back together and let the adjuster ride on the shaft for now. I know it's not right, but what else can I do? I don't have the time or the knowledge right now to dive into this. I would guess the new seal would keep the gear oil in and lubricate the gears to prevent anymore damage.

If anybody has any more ideas or suggestions, please post.

Thanks

 

[Einst-Hawk]

Also, Thank you Roadie for explaining the tabs thing. I was so confused about that.

 

[The_Roadie]

You can leave the driver's side half-shaft out, and in 2WD mode, you'll be OK.

The driveline binding in 4HI mode comes from the transfer case locking the drivetrain fore/aft, and from the different turning radii of the two diffs. I did this graphic up YEARS ago to explain how you can have an open (non-locked) diff in the front, and still get binding.

 

[BoldAdventure]

Great, I have the same puddle under mine....... And I just changed my fluid the other day.

 

[Einst-Hawk]

Thank you roadie for the diagram. that was very informative.

Now back to the issue at hand. I was screwing around trying to figure out how to make this work. No matter how I tried, the adjuster would not screw in. I saw the threads in the housing. BTW they look pretty good. I don't know why I didn't see them this way before. Maybe I was not at the right angle I guess. I put the adjuster in and then put the seal behind it, sort of like a test fit. The seal was sticking out so far that I thought "This will never seat flush".

Then it hit me. Maybe the half shaft pulled out the inner bearing too. So I took my seal driver and punched the inner bearing back.
It worked!! The adjuster screws in. I'm in the process of trying to screw it all the way in now. I'm taking a 1/4 in. steel dowel rod, hitting the back end with a hammer, and working it against the tabs to move it. I think I'm going to be here awhile.

Just wanted to update

 

[fishsticks]

If you have a piece of bar stock, you can make a spanner wrench. Measure the distance between holes on your old cap, then drill at that same distance in the bar stock and use 1/8" bolts/nuts. Using a punch of any kind might mar up the holes in the cap.

There are two caps (adjusters). The one on the oil pan side sets the backlach between the ring and pinion. The one closest to the outside (the one you are working with) sets the bearing preload. You need to get that one pretty tight in there or the pinion may walk and break under any sort of stress in 4WD. The housing (and those threads) are aluminum, so one slip of a punch WILL mar those threads and make your life much more difficult.

 

[Einst-Hawk]

That is an outstanding idea fishsticks. Wish you had posted earlier. I did manage to get the adjuster tight by using the steel dowel. I made sure that I did not mar anything. Got the seal on too and its flush.

I am now in the process of putting everything back together. I'll post back to let everyone know if I managed to avoid the 'sh*t in the road'

Thank you everyone for your advice.

 

[Einst-Hawk]

Success!!

I got it all back together and no leaks!!

Thank you members of GMTNation! I hope that my experiences with this issue can help someone else on here.

http://gmtnation.com/images/smilies/raspberry.gif

 

[Einst-Hawk]

Success!!

I got it all back together and no leaks.

Thank you everyone for your help. I hope this thread can help someone else in this situation.

GMTNation is the best

 

[Texan]

This was a interesting thread. I am not a 4X4 type, but have messed with diff. years ago.
From what I remember, that adjusting ring is used to preload the bearings.
When I was a teenager I had a WW2 Jeep that I would take down in the river bottom.
One of the things I learned was, when you get a 4X4 stuck, you are really stuck.