Front Axle 4WD Disconnect

[Zero]

We need someone to figure out how / what / and why these are failing and come up with a new part that will solve the problem. or maybe some kind of miant. we can do on our own to prevent failure.

[05ls_soldier]

I think a lot of the issue with mine was not being carefull with 4wd engagement. I should be able to tell more when I get it apart, but im not going to do that untill I have the parts to fix it. Still looking for them, everywhere I have looked only sells complete carrier assembly (driver and passenger side) Trying to find someone to seperate it so I can afford to fix and lift. Maybe annual or bi-annual regrease would help?

[bgwolfpack]

We need someone to figure out how / what / and why these are failing and come up with a new part that will solve the problem. or maybe some kind of miant. we can do on our own to prevent failure.

Since these seem to have become an issue, for some reason or another, it would be helpful if anyone who has had this problem to do a write up and fix. Zeros thought on maintenance seems warranted given the amount of off road abuse to these vehicles by members and their zealous natures for the less than pavement.

[05ls_soldier]

Once I get the parts I will gladly do a write-up. I believe there are a couple on the OS, but I dont have the time to look it up right now. Unfortunatly I will be in Wyoming for cold weather training in Feb. So it wont be untill mid-March when I get the time again.

[Trail X]

So I finally had a free weekend to get some work done on the truck... so the actuator demanded some attention. I got the assy out and was able to crack it open... it was worse than I had originally figured.

So, as of now, the truck is not drivable, as the intermediate shaft needs support, otherwise it will destroy the inside of the oil pan.



You have to remove one of your end links to remove the CV shaft... mine weren't cooperating one bit... so bye bye!



The shaft and disconnect assy once removed:



You can see here, the seal is ruined and there's wear on the CV shaft:



I had to really wrestle with this... there's a tight fit between the assy and the oil pan. After going through a few water holes, I guess dirt and silt gets in... and just becomes glue. I had to pry on it for a good 20 minutes before getting it out.



Cracked open... my first look... worse than I thought:



View of the fork and shift collar. Fork is not broken, but extremely worn:



The pieces... as you can see, there were some issues with the bearings... out of the 3 (I think) bearings, none survived, and the outer two were utterly destroyed. The needle bearing rollers were basically dust:



Interior seal... still intact, but even then, the bearing was destroyed.



I'm going to take it to work to clean the grease off the parts and try to figure out what exactly needs to be replaced. I had ordered some preliminary parts, but it needs much more work than I had imagined.

[bgwolfpack]

Judging from that I wonder if you shouldn't go through the whole front end.

On the bright side it's time out of the house spent with your truck.

[The Roadie]

Ick. Our Dorman buddy will love to see these and get your broken parts. I alerted him.

[Trail X]

...broken parts.

Well that's just it... nothing really broke. That outer seal must have rotted out, which just lead to extreme wear. And the worst part, is there's no real warning or bad noises. Just the occasional rattle (and 4WD being temperamental).

This is how worn the outer bearing was... left, the old bearing, right, a new bearing.


The fork was not broken, however, if you notice at the ends of the fork prongs, they have what looks like wear pads. Only these pads engage the shift collar. As you can see here, there is no left pad, which apparently was worn away because of the CV shaft sitting angled, due to the death of the outer bearings.


This is another example of the wear. This is a thrust washer that sits between the input and output gears. Due to the offset of the outer gear, it wore away the interior of the washer into a bevel.


I'd recommend everyone check their passenger side CV tripod joint. Jiggle it, if there seems to be excessive play, take it out and look at your bearings... changes are, they may be destroyed.

I still haven't cleaned these suckers up enough to really look at them... we have a degreaser at work, I'll try to clean them up more tomorrow.

[intimadatorsquizz]

Dorman is still working on the fork. We'll have rebuild kits available and a outer housing soon. James check your outer housing the few bad ones I have here are junk. When the outer bearing goes it starts to ride in the aluminum housing and wears it down bad. So bad that the new bearing won't press in it just drops right in. Let me know if you have trouble getting parts from the OE if I can help you I will.
jsquicci@dormanproducts.com

[Trail X]

Thanks Jim. I was looking at that, from what I can tell, none of the bearings spun, however I'll know more once I clean everything up and start the reassembly process.

Which parts will be in your rebuild kit? 3 bearings, 2 shaft seals, the 3 thrust washers, and a fork? Do you plan to include the 'gears' and collar in the kit? I notice some wear on the gears' bearing surfaces which worries me about using them again. I'm afraid they're just going to eat the bearing rollers up. However, if I have to purchase those, I might as well just purchase a junkyard unit.

[intimadatorsquizz]

Thanks Jim. I was looking at that, from what I can tell, none of the bearings spun, however I'll know more once I clean everything up and start the reassembly process.

Which parts will be in your rebuild kit? 3 bearings, 2 shaft seals, the 3 thrust washers, and a fork? Do you plan to include the 'gears' and collar in the kit? I notice some wear on the gears' bearing surfaces which worries me about using them again. I'm afraid they're just going to eat the bearing rollers up. However, if I have to purchase those, I might as well just purchase a junkyard unit.

James we'll have a kits with the 3 bearing 2 seals a fork. The thrust washers usualy survive, but not in your case. If you need gears let me know I do have some good used gears here unless you can find a used unit. Oh also I have thrust washers from some of the used pieces. We'll also be doing a kit for the AWD TBSS. I've got a couple of those failed units here as well and they take the same thrust washers.

email me jsquicci@dormanproducts.com

[Hatchet669]

sweet cant wait for the kit to come out.. i need to rebuild mine i think...

[Trail X]

James we'll have a kits with the 3 bearing 2 seals a fork. The thrust washers usualy survive, but not in your case. If you need gears let me know I do have some good used gears here unless you can find a used unit. Oh also I have thrust washers from some of the used pieces. We'll also be doing a kit for the AWD TBSS. I've got a couple of those failed units here as well and they take the same thrust washers.

email me jsquicci@dormanproducts.com

Is the stock fork aluminum? It looks/feels like it. Will your replacement be aluminum too?

As for the thrust washers... I realized that us lifted guys have a slightly more complex issue. I assume that the samples you have are from non-lifted guys. With a non-lifted truck, there's no moment being forced on the CV shaft due to the tripod joint boot being bent (as a lifted truck's is all the time).

That moment creates a couple across the front two bearings... down on the outer-most bearing, up on the outer-gear bearing. This cocks the whole outer gear up at an angle. That induced couple is why my outer-most bearing was completely eaten away on one side only... just as my shift fork is eaten completely away on one side... and the other shows normal wear.

[05ls_soldier]

James, I don't want to hi-jack the thread, but I thought some more information might be nice on here. Fell free to delete if need be!

I just got back from our local dealership pricing out the parts. For all the parts Inside of the passenger side carrier they wanted $420. Now with mine I know it is my gears that are bad, that alone was 217 dollars.

Part# Description Price
26053326 Bearing $9.61 (I believe 2 are needed)
12471625 Washer $4.25
12471628 Gear $111.89
26036092 Sleeve, FR $106.48
12479132 Fork $64.77
12471629 Washer $4.25
12471627 Gear $105.52
12471623 Washer $4.25


If I missed anything please let me know.


Also on a sad note, I visited 4 Junk-yards today and none of them had any of these.!

[Trail X]

There are three bearings total in the disconnect. All should probably be replaced. There are also two shaft seals: 12479302 (outer), and 15801507 (inner). Your inner one will probably be fine, but the outer will need to be replaced if you replace the outer bearing.

[intimadatorsquizz]

The fork will be a totally different as for the material I'm not saying as of yet. Also I've seen 3 people need that outer half of the housing and that it over $200.00 by itself. James I don't know if the truck we're lifted that i got my parts from, but I'm pretty sure 1 or 2 of them were. And yes there is 3 bearing and they're all the same and all should be changed. Oh and another thing there have been guys that have needed the shaft that goes thru the oil pan and that's another $260.00

[bgwolfpack]

James, what's the greatest culprit here, the lift angle or the water seepage past the seal?

[Trail X]

James, what's the greatest culprit here, the lift angle or the water seepage past the seal?

Improper lubrication is the first thing (I think this unit really should have been a liquid lubricant vs. the grease). I'd recommend everyone pull out their passenger side CV and re-grease the bearing visible there. Once that one fries, I assume it just grenades into the unit, slowly affecting more and more components. This degradation happens faster due to a lifted TB's CV angle.

The busted outer seal just allowed the grease to dry up that much faster. Either way, I assume it's just a matter of time.

[Zero]

is there is specific type of grease you would recommend? I have a metallic rattle on the driver side that seems to be coming from the from drivers side wheel area. And now the front sway bar link on that side is making noise.

Would you say that the rattle i hear only on the driver side and mainly when I turn right would be the same issue you had??? I checked the brake shield. It seems to be clear. But the rattle is still there.

thanx

Z

[Trail X]

Some pictures of the wear now that I have the parts cleaned:

Fork, notice the wear pad is gone on the right prong:


Outer gear, notice the groove worn into the gear:


Inner gear, not as bad as the outer, but still shows galling:


Where the CV shaft wore through the bearing and contacted the housing. The bearing still fits snug, so it should still work:


Showing the old thrust washer vs. the new thrust washer. Old on top:


Inner thrust washer, worn due to the offsetting of the outer gears pushing on the inner gear:


Middle thrust washer, cupped due to the CV shaft poking it:


The inner shaft seal installed on the inside housing, the only item still intact:


Assembled, showing how it works, for your reference:

Showing the assembly in 2WD mode:
The top gear would be connected to the intermediate shaft, the lower one connected to the CV shaft. When in 2WD mode, the two gears counter-rotate due to the freewheel of the differential.


4WD mode:
The spacer under the fork is there to simulate the actuator pushing on the fork... not part of the assembly.