4wd Axle Disconnect...Replace or Repair

BanditGTP

Original poster
Member
Jan 2, 2013
89
Central NJ
I looked into something I came across the other day while trying to troubleshoot my transmission problem on my 03 Envoy XL. This is a video of the passenger side CV axle going into the Axle Disconnect. I originally thought it was not fully seated but it feels like the internal retaining clip is still holding.

Loose axle at axle disconnect

Not having ever done a repair on this, I’m not sure of what is actually bad. Would it just be a seal or bearing that's bad and not holding the axle solidly in place or is the entire axle disconnect shot and needs to be replaced?

I haven’t used 4wd in over 2 years and at this point in my trucks life, I don’t foresee the need to use it. I think I’ve seen in the past there is a way to just eliminate it. Is it just a matter of removing both axles?
 

TollKeeper

Supporting Donor
Member
Dec 3, 2011
8,047
Brighton, CO
Wow, take 2 of the same problem in a month...

For the moment, I would say disconnect your front axle shaft, and CV axles, until you get your transmission fixed. You didnt say what your problem was/is with the transmission. But this will be a start.

Once you get your transmission sorted, you can solve your disconnect problem.

I personally do recommend in just replacing the disconnect. It likely will not survive the removal anyways (they hardly ever do).
 

Mooseman

Moderator
Dec 4, 2011
25,257
Ottawa, ON
That is bad. I'd expect the disco to be damaged and non-repairable. You can remove both axles and the front driveshaft to convert it to 2WD. Leaving in the disco and its actuator will avoid the service 4x4 light from coming on. You can also put in some Gatorade caps to close off the holes in case you change your mind and want to return to 4x4.
 
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pm789632147

Member
Apr 13, 2020
5
pa
That is bad. I'd expect the disco to be damaged and non-repairable. You can remove both axles and the front driveshaft to convert it to 2WD. Leaving in the disco and its actuator will avoid the service 4x4 light from coming on. You can also put in some Gatorade caps to close off the holes in case you change your mind and want to return to 4x4.
Thank you,good info.
 

coolride

Member
Aug 23, 2019
596
Adirondacks
Something to remember is the movement that you see at the tripot, is not the same as movement in the axle bearing. That's two different parts. You might use an inspection mirror to get your eyes right on the shaft (tucked in behind the (tripot.) Then check for movement again.
 

Mektek

Member
May 2, 2017
656
FL
It depends a lot on mileage. Over 200k there will be wear on the bearing races and unless you are really determined it is probably better to replace the whole thing.
 

paul2005tb

Member
Nov 26, 2014
299
Massachusetts
Similar issue, I installed a new front driver side CV axle assembly today. But the retaining clip does not seem to be grabbing in the transfer case female side. Even after striking the hub side with a sledge it still is easily pulled out of the transfer case side. I can see that it needs to go in another 1/2 inch. Not sure what else I can do. Can this retaining ring seat itself after driving a bit. Seem it should.

I don't know why the engineers just didn't have a bolt on solution.
 

Mooseman

Moderator
Dec 4, 2011
25,257
Ottawa, ON
It should click right in when pushing the axle into the differential. Maybe try pulling it back out and rotating it to another position. I have found sometimes I had to use the axle's sliding tri-pot as a pushing "slide hammer" to get it in.
 

TJBaker57

Member
Aug 16, 2015
2,897
Colorado
Similar issue, I installed a new front driver side CV axle assembly today. But the retaining clip does not seem to be grabbing in the transfer case female side. Even after striking the hub side with a sledge it still is easily pulled out of the transfer case side. I can see that it needs to go in another 1/2 inch. Not sure what else I can do. Can this retaining ring seat itself after driving a bit. Seem it should.

I don't know why the engineers just didn't have a bolt on solution.

When you had it all apart, did you look inside the disconnect/bearing assembly to see that the path was clear?

Reason I ask is this: inside are two gears. One connected yo the intermediate shaft and thensecond to connect to the CV axle. Between the two is a thrust washer to keep them just slightly separated.

When my disconnect failed, the thrust was her had worn thin enough to slip out of place. I imagine that if this happened it might stop the cv axle from being inserted far enough to lock in place?

They are known to be pretty stubborn, in my case I had to remove the whole business together, CV axle and disconnect to get them out. I could not get the CV axle to release from the disconnect.
 
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Mooseman

Moderator
Dec 4, 2011
25,257
Ottawa, ON
I'm guessing that if you install the shaft and go out for a short drive, it will click into place.
Not if there is some sort of problem inside the diff. It shouldn't be that bad to get it in. If it won't go in without excessive force and it is forced in by the suspension movement or doesn't go in at all, this can cause damage to the diff or the seal.
 
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paul2005tb

Member
Nov 26, 2014
299
Massachusetts
it is definitely sliding in far enough to engage the plines. I know this because it easily slides in . The front wheel drive has always worked fantastic, I have never had a problem. when I slide it in all seems right it just doesnt go that last 1/2inch. When I look at the other side i notice that the tripod acorn body butts up against the transfer case, maybe a 1/8 to a 1/4in space, but the the driver side is more like `1/2 to 1in between. I can turn the axle just fine so I know it is engaged with the transfer case female splines. Ive whacked the end of the axle with a sledge.. maybe I will put a bigger sledge to it and maybe that will do the trick.
 

TJBaker57

Member
Aug 16, 2015
2,897
Colorado
When my disconnect failed, the thrust was her had worn thin enough to slip out of place. I imagine that if this happened it might stop the cv axle from being inserted far enough to lock in place?


Well it has been like 6 years since I replaced my disconnect and my memory was unclear so I just took out my spare for a look see.

It appears that the thrust washer is normally in a place that limits insertion of the CV shaft so this idea is sort of shot down. While I was looking it over I measured the distance between the thrust washer and the shelf where the snap ring would click into place. A mere 3/8 inch maximum from the thrust washer and the furthest extent of the cutout shelf the snap ring would seat into. If this is the case then the furthest part of the snap ring from the end of the CV shaft would need to be no more than 3/8 inch.

Is it possible an aftermarket CV shaft might have this dimension a fuzz too great?PXL_20210905_184739878.NIGHT.jpg
 
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paul2005tb

Member
Nov 26, 2014
299
Massachusetts
When you had it all apart, did you look inside the disconnect/bearing assembly to see that the path was clear?

Reason I ask is this: inside are two gears. One connected yo the intermediate shaft and the second to connect to the CV axle. Between the two is a thrust washer to keep them just slightly separated.

When my disconnect failed, the thrust was her had worn thin enough to slip out of place. I imagine that if this happened it might stop the cv axle from being inserted far enough to lock in place?

They are known to be pretty stubborn, in my case I had to remove the whole business together, CV axle and disconnect to get them out. I could not get the CV axle to release from the disconnect.
I did not look past the rubber seal, inside the transfer case insert. Im not sure what the "disconnect" is. I am replacing the entire CV axle assembly, on the outboard side is the threaded end for the hub mount and on the inboard side is the splined end with the snap ring. Im scratching my head on this one, it should pop into place with the force of a sledge and when in place it should be able to stay in there when I grab the axle and pull.

in thinking through the safety issues. As I see it, my wheel is held in place by a massive lower and upper ball joint. Neither steering nor stopping is dependent on that snap ring. That snap ring does not effect the safety of my vehicle. I feel confident I could put this back together and drive it around and see what happens. I could then see if it snapped into place. This is looking like an option because whacking that axle on the hub side with a sledge has its own risks.
 
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TJBaker57

Member
Aug 16, 2015
2,897
Colorado
not look past the rubber seal, inside the transfer case insert. Im not sure what the "disconnect" is. I am replacing the entire CV axle assembly, on the outboard side is the threaded end for the hub mount and on the inboard side is the splined end with the snap ring

Some nomenclature is in order.

The transfer case is bolted to the rear of the transmission under the center of the truck.

The front differential is bolted to the drivers side of the oil pan.

The intermediate shaft bearing assembly is also called the front axle disconnect or the splined disconnect and this is the item that is bolted to the passenger side of the oil pan.

The picture I last posted is looking into the front axle disconnect where the passenger side CV axle goes in. If the CV shaft does not insert the whole distance it is designed to do and lock in place I don't know if there is enough movement when the suspension moves to the limits for it to release but I believe it will likely lead to accelerated wear of the outer bearing of the front axle disconnect. This outer bearing is already known to be problematic issue for these trucks.
 
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paul2005tb

Member
Nov 26, 2014
299
Massachusetts
Many thanks for that. My understanding is that both the left and the right front CV axles are exactly the same.
 

chris68369

Member
Nov 18, 2018
12
Michigan
I looked into something I came across the other day while trying to troubleshoot my transmission problem on my 03 Envoy XL. This is a video of the passenger side CV axle going into the Axle Disconnect. I originally thought it was not fully seated but it feels like the internal retaining clip is still holding.

Loose axle at axle disconnect

Not having ever done a repair on this, I’m not sure of what is actually bad. Would it just be a seal or bearing that's bad and not holding the axle solidly in place or is the entire axle disconnect shot and needs to be replaced?

I haven’t used 4wd in over 2 years and at this point in my trucks life, I don’t foresee the need to use it. I think I’ve seen in the past there is a way to just eliminate it. Is it just a matter of removing both axles?
Haaa I just fixed this yesterday. It's not to bad. If anyone has this problem then you are not alone. Inside the 4wd disconnect their are three bearings and two seals, inner and outer. After time the outer seal starts to wear and water gets in to the grease. After time the grease washes away and your grinding your bearings up. Their are two bearings that meet with the cv axle. The first bearing closest to the seal usually is non-existent if you have that much play. You'll also notice a grinding when turning your wheels while in 4wd. If you catch it quick enough you'll only need to replace the 1st bearing and outer seal. Take tire off and take out upper and lower ball joint nuts, remove CV axle nut, and move whole hub assembly onto a jacket and. No need to remove rotor, caliper, and wheel hub. To remove CV axle grab a long pry and sledge hammer. Put tip of pry bar on one of the notches on CV axle. Should pop right out. However if it keeps rattling around and not pop out, then most likely the old needle bearings are jammed in their wedged and making it stuck in place. The bolts on 4wd disconnect housing are 15 mm. 4 of them connect to the oil pan. One on each corner. Remove those and use CV axle as leverage to pop out 4wd disconnect. Some may have issues that I had where CV axle pops out but 4wd disconnect will not no matter how much you pry, tap, smack, yell and scream insults at it. Flipping it off as well does help with emotions with it not wanting to budge. So then you can take off the disconnect housing held in by the 5 additional 15 mm bolts. These bolts are smaller than the ones holding in the actual disconnect to the oil pan. Remove it and their will be bearings, grease etc. It's pretty straight forward when taking it apart. Do what you can to remember where each part goes. Clean up and inspect the gears and fork. Remove old seal and tap out the bearing race. Then flip over and tap out the other bearing that connects with the gear and aluminum fork. After tapping in bearing then flip over and put it a new seal. Then while putting back together add new grease and butter that thang up. Don't use to little and don't use to much. Just get it to coat every nook and cranny and every piece of metal. Then use silicone for when you put it back on water doesn't get in and destroy what you just fixed. Here is a link that I found that may help you find the part numbers you need.

 
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flyboy2610

Member
Aug 24, 2021
460
Lincoln, Ne.
Thanks for that, Chris68369! I read somewhere where one guy drilled and tapped his disconnect for a grease zerk. I like that idea, may have to do that to mine (and the wife's '06 TB).
 
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paul2005tb

Member
Nov 26, 2014
299
Massachusetts
They do show the same part number online at a GM wholesale parts site
Thanks, ..update, so I jacked up the hub at the lower ball joint, this lined up the shaft perfectly straight. I then put the axle nut on , put the socket on and then whacked it with the sledge. It locked into place!! Mission accomplished.

Now, I'm going to replace the torn boot on the removed used axle and put it in storage for the next torn boot because I just cant sleep at night if I toss out the old axle just because one boot was torn. I realize this is not cost effective because an entire new axle assembly cost 75$ and the new boots cost 35$ (+200$ of my own labor) .
 
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chris68369

Member
Nov 18, 2018
12
Michigan
Thanks for that, Chris68369! I read somewhere where one guy drilled and tapped his disconnect for a grease zerk. I like that idea, may have to do that to mine (and the wife's '06

Haaa I just fixed this yesterday. It's not to bad. If anyone has this problem then you are not alone. Inside the 4wd disconnect their are three bearings and two seals, inner and outer. After time the outer seal starts to wear and water gets in to the grease. After time the grease washes away and your grinding your bearings up. Their are two bearings that meet with the cv axle. The first bearing closest to the seal usually is non-existent if you have that much play. You'll also notice a grinding when turning your wheels while in 4wd. If you catch it quick enough you'll only need to replace the 1st bearing and outer seal. Take tire off and take out upper and lower ball joint nuts, remove CV axle nut, and move whole hub assembly onto a jacket and. No need to remove rotor, caliper, and wheel hub. To remove CV axle grab a long pry and sledge hammer. Put tip of pry bar on one of the notches on CV axle. Should pop right out. However if it keeps rattling around and not pop out, then most likely the old needle bearings are jammed in their wedged and making it stuck in place. The bolts on 4wd disconnect housing are 15 mm. 4 of them connect to the oil pan. One on each corner. Remove those and use CV axle as leverage to pop out 4wd disconnect. Some may have issues that I had where CV axle pops out but 4wd disconnect will not no matter how much you pry, tap, smack, yell and scream insults at it. Flipping it off as well does help with emotions with it not wanting to budge. So then you can take off the disconnect housing held in by the 5 additional 15 mm bolts. These bolts are smaller than the ones holding in the actual disconnect to the oil pan. Remove it and their will be bearings, grease etc. It's pretty straight forward when taking it apart. Do what you can to remember where each part goes. Clean up and inspect the gears and fork. Remove old seal and tap out the bearing race. Then flip over and tap out the other bearing that connects with the gear and aluminum fork. After tapping in bearing then flip over and put it a new seal. Then while putting back together add new grease and butter that thang up. Don't use to little and don't use to much. Just get it to coat every nook and cranny and every piece of metal. Then use silicone for when you put it back on water doesn't get in and destroy what you just fixed. Here is a link that I found that may help you find the part numbers you need.

I should mention that I originally had an issue where sometimes on the highway after changing a lane it would always feel like I had a bad ball joint or tie rod. It would sway in the front and after driving straight for a minute or two would be fine. Then I found out the seal on the front differential driver side was leaking. After replacing I checked to make sure the 4wd was able to go without leaking diff oil. That's when I heard grinding from the passenger side Everytime I turned in 4wd left or right. That's when I noticed play on the CV axle. After replacing the outside seal and two bearings that connect to with CV axle I no longer have this problem. If you know you have this problem but decide to wait please don't. Where the very front bearing is I found started to scar up from the CV joint. I can see after time it wears it out to where you can not tap in a new bearing and have it stay in place. These are not cheap to replace. Took me maybe 2 hours to fix. You can get all the parts from Amazon as well. I found out the driver side outside seal is a dealers only part but you can also buy on Amazon.
 

chris68369

Member
Nov 18, 2018
12
Michigan
Thanks for that, Chris68369! I read somewhere where one guy drilled and tapped his disconnect for a grease zerk. I like that idea, may have to do that to mine (and the wife's '06 TB).
Not a bad idea but after seeing what it's like inside it is pretty tight in their. Even with a grease zerk in place I can see where grease may not be able to go past the aluminum fork. I would rather just take the cover off to inspect and add grease if necessary. Doesn't take long to do this. Theirs no need to take off rotor, caliper, wheel hub off, or tie rod. I just took out the upper and lower ball joint nut and bolt and moved the assembly on top of a jack. I only took me about 20 min to remove all of that. Plus you will be able to look at the bearings and see if any would need replacement. I'm thinking to inspect at least 1 time a year before winter hits in michigan
 

paul2005tb

Member
Nov 26, 2014
299
Massachusetts
great info, when I was replacing my driver side CV axle I noticed that oil leaked out onto the floor during the replacement. I had better keep track of that seal.
 

chris68369

Member
Nov 18, 2018
12
Michigan
U fortunately this is how many people end up destroying their front differential. Your not always able to see it drip unless it's a good amount leaking out. Don't buy any aftermarket seals because they wear out really fast. Buy the gm seal. Those are also in Amazon for decent price. Don't need to take off caliper or rotor as well as tie rod. Just disconnect upper and lower ball joint, remove axle nut, then swing onto a jack stand and it will hold their just fine. Also after removing seal check the bearing. Then before reinstalling with new seal tighten the big nice and snug. This is the nut that has the bearing inside. You can remove it if you need to replace the bearing that's inside that nut.
 

TollKeeper

Supporting Donor
Member
Dec 3, 2011
8,047
Brighton, CO
I found the cheapest place to get the front diff seals was directly from a GM dealer..
 

chris68369

Member
Nov 18, 2018
12
Michigan
Unfortunately that wasn't going to happen for me. Lol. I asked them first and they said would take from 2-3 days to receive it. I have Amazon prime and got it the next day. I may order a few more of them as well as bearings so if it does happen again I already have it. I sure hope many others are able to get them from the dealer so they can fix it on the spot
 

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