So I got this truck with 170k and was told there were no check lights and 4x4 worked.. well I’m such a trusting guy I paid the guy and drove home. (Traded a 06 Pontiac G6 GTP with 160k and $600) well by the time I have a chance to really look at it I realize there is a check engine light and I have service 4x4. I bought a bluedriver when I was driving the g6 (one of the Best Buy’s I’ve ever made 😬) and found it to be a evap issue. I was able to tell the previous owner had already replaced gas cap so I replaced purge and vent valve.. I don’t remember what exactly the parts were called but I did it and it has been running great ever sense.. now I focus on 4x4 issue. I love how my obd reads drivetrain codes so it sends me in the rite direction. It told me to check front axle actuator and to my surprise it was already taken off leaving just the wire hanging.. I’m not big on gettin such a cheap part from u pull u pay but the person that took it off didn’t put the 2 bolts back in. I was able to find the actuator in the trunk wit no bolts so I spent the 13$ and got a used one. After a few weeks of lookin on this page and like every YouTube vid I was able to rule out transfer case issue.. I simply crawled under the truck while is was is 2wd and checked to c if front drive shaft would spin freely and it did. So I put it in 4x4 and c if it would still spin and it was locked. At least I’m hoping that’s a good way to check 🤷♂️🤔 anyways thats about where I’m at.. I also noticed the front passenger cv has a TON of movement do I replace just the cv axle of am I looking at replacing the 4x4 disconnect. FYI I’m pretty new at working on any vehicles. I’ve learned by taking the time to c how the job is done and what steps are takin make it even possible
2002 envoy front def issue
- Thread starter Kr.jr270
- Start date
Mooseman
Moderator
Do you mean the CV axle moves around within the disco? In that case, the disco needs to be replaced.
Another quick check is to put it in 4Hi then jack one (only one) front wheel off the ground a bit. See if you can rotate the wheel. If you can rotate the front wheel then get low to where you can turn the wheel and see the front driveshaft between the transfer case and front differential. Does that spin when you turn rotate the front wheel? If yes then the trouble likely lies somewhere at the transfer case. If no then the trouble is likely at the front disconnect.
I’m not sure what the disco is.. I’ve done a lot of research and that has never came up
I have had all 4 wheels up before just checking everything out to see what spins and what doesn’t. I did notice even with the truck in 2wd the front drive would still spin. Now I didn’t have the balls to reach up and c if I could stop it and also with the truck in park I still had wheel spin.. 🤷♂️ But I did turn the key on and check the front drive shaft and it wouldn’t spin only in 4hi 4low and I did jack just the passenger wheel up put in 4hi and the wheel would spin.. from all the info I have read on here it’s the 4wd disconnect and from the looks of it can be a real pita I could possibly but replace the shift fork?
Everything here points to the front axle disconnect.
( "disco" = disconnect, as in front axle disconnect.)
Something I have not seen mentioned on the internet is that the actuator can actually move full travel and report back to the computer that it has shifted to the correct position, when in fact the disconnect has not shifted internally. This is because inside the actuator is a spring that the mechanism pushes against. The spring is there to protect items like the shift fork inside the disconnect in the event the gears are not properly aligned to shift. The tension is absorbed by the spring and when the gearing inside the disconnect aligns the spring pushes the shift fork moving the gearing in to proper position. I know this because thats how my TrailBlazer came to me. Inside the disconnect a shim/thrust washer had worn and slipped into a spot that blocked the gearing from moving.
Here is the shim...
Here is the actuator in the off position...
And here is the actuator in the 4wd on position. I'll point to the spring seen inside....
If you wind up having to remove your disconnect, and it sounds like you will, proceed cautiously. Excessive force is not your friend here. Pictures and stories of broken oil pans, pieces of broken disconnects stuck in oil pans, and so on can be found scattered on the web.
Patience is almost certainly required here.
( "disco" = disconnect, as in front axle disconnect.)
Something I have not seen mentioned on the internet is that the actuator can actually move full travel and report back to the computer that it has shifted to the correct position, when in fact the disconnect has not shifted internally. This is because inside the actuator is a spring that the mechanism pushes against. The spring is there to protect items like the shift fork inside the disconnect in the event the gears are not properly aligned to shift. The tension is absorbed by the spring and when the gearing inside the disconnect aligns the spring pushes the shift fork moving the gearing in to proper position. I know this because thats how my TrailBlazer came to me. Inside the disconnect a shim/thrust washer had worn and slipped into a spot that blocked the gearing from moving.
Here is the shim...
Here is the actuator in the off position...
And here is the actuator in the 4wd on position. I'll point to the spring seen inside....
If you wind up having to remove your disconnect, and it sounds like you will, proceed cautiously. Excessive force is not your friend here. Pictures and stories of broken oil pans, pieces of broken disconnects stuck in oil pans, and so on can be found scattered on the web.
Patience is almost certainly required here.
I could take off the actuator and take a look at it.. it’s the one I got from u pull. But with the cv being sooooo loose I’m sure is the “disco” that needs to be worked on. And ya I’ve read a few stories on how the corrosion can make it very difficult so ya when I’m ready to take that on I will be following all the steeps one by one. Maybe I’ll be in the 10% that just pop off with ez 🤦♂️🤣🤷♂️
I’m kinda feeling like getting rid of it while it still runs great and looks pretty. But my other half is telling me just get the work done learn something new and hope that’s all it need to have 4x4 working. I was way surprised with the condition it was in having 180k everything works even the paint is dam nice. I’m sure a lot of it has to do with me being the 2nd owner who ever had it b4 took really good care of it
You could pull the actuator off then see if you can manually push in the the hole and shift the disconnect. It is spring loaded so if you push it in it will pop right back out but you might confirm that it at least moves. It's been 5 years since I did mine so I cannot remember how much force that would require but I think I could do it on my new replacement disconnect. There is a good writeup somewhere that shows the disconnect disassembled for service, maybe at offroadtb.com....yep!
offroadtb.com
Here's mine when I opened it up...
Front Axle 4WD Disconnect Rebuild | offroadTB.com
offroadtb.com
Here's mine when I opened it up...
Mooseman
Moderator
Unless you find a good working disco at a u-pull, you can find better priced ones on eBay. Just be sure you get the one for 4x4 and not the AWD version. The way you can tell is the AWD version will not have the hole for the actuator and the 4x4 version also usually comes with the actuator.
If you do get a used one, take it apart as per the article linked by @TJBaker57 , clean it out and put in some fresh grease if it's in good condition.
Front Axle Disconnect Actuator Assy For Trailblazer Envoy Rainer Bravada 4X4 4WD | eBay
Find many great new & used options and get the best deals for Front Axle Disconnect Actuator Assy For Trailblazer Envoy Rainer Bravada 4X4 4WD at the best online prices at eBay! Free shipping for many products!
rover.ebay.com
If you do get a used one, take it apart as per the article linked by @TJBaker57 , clean it out and put in some fresh grease if it's in good condition.
Ok thank you guys very much! I was considering going to u pull so I know what to expect but at the same time I hate to do all that work and something on that one be junk.. thank u again!Unless you find a good working disco at a u-pull, you can find better priced ones on eBay. Just be sure you get the one for 4x4 and not the AWD version. The way you can tell is the AWD version will not have the hole for the actuator and the 4x4 version also usually comes with the actuator.
Front Axle Disconnect Actuator Assy For Trailblazer Envoy Rainer Bravada 4X4 4WD | eBay
Find many great new & used options and get the best deals for Front Axle Disconnect Actuator Assy For Trailblazer Envoy Rainer Bravada 4X4 4WD at the best online prices at eBay! Free shipping for many products!rover.ebay.com
If you do get a used one, take it apart as per the article linked by @TJBaker57 , clean it out and put in some fresh grease if it's in good condition.
If you're considering a u-pull take theirs out first so you learn the ins and outs of it before you get to yours. Then if something breaks at the salvage yard you haven't busted your own!
Ya my though exactly. Because we all know how much of a pain they can be. At my u pull there are quite a few TB and a few envoys should I go ahead and grab a newer TCCM while I’m there. My envoy is the 2002 so I’m thinking y not 🤷♂️🤷♂️ And is there anything else I should consider replacing in my 02 it’s kinda a far drive so wanna make a good trip
Mooseman
Moderator
The TCCM is a good idea. Other than that, can't think of anything except maybe spares for common failure parts. Throttle bodies of yours' age are starting to fail with broken internal gears. If you see a new'ish fan clutch, you could grab that too (don't bother with Dorman). Same for a water pump. I once grabbed a brand new ACDelco pump off a Silverado. Starter motor would be another one. Front hubs are also popular. It happens when vehicles are scrapped right after a new part is installed.
Ok cool I’ll definitely keep my eye out for those parts.. and if I do find a good disco with a good cv I could just get both? Or should I just opt for new cvs
Mooseman
Moderator
Mooseman
Moderator
The flexible rubber covering each of the joints. Originals are actually hard plastic while most aftermarket are softer rubber.
My bad, actual term is "boot", not bellow.
My bad, actual term is "boot", not bellow.
HARDTRAILZ
Moderator
- Nov 18, 2011
- 49,665
The stock CV boot are not hard plastic. Most aftermarket are similar heavy duty rubber except for Cardone. Some have more pleats than others though.
Mooseman
Moderator
HARDTRAILZ
Moderator
- Nov 18, 2011
- 49,665
Hard plastic would crack, not flex like the boots need to with suspension cycling 
paul2005tb
Member
Well, less than 2 years after installing my new aftermarket CV joints and axles I notice that grease is coming out of my driver side CV joint boot. Is it possible that my 3in suspension lift causes the boot to crack so fast, I drive like an old lady, all highway.
My solution is going to be to clean the boot good and then buy some of that rubberized plumbing tape and tape around the crack. I am not going to replace an entire axle again simply for a failed boot.
My solution is going to be to clean the boot good and then buy some of that rubberized plumbing tape and tape around the crack. I am not going to replace an entire axle again simply for a failed boot.
Yes - a big lift will cause shortened lifespan of the cv axle components.
The tape wont work - it cant stand up to the flexing for any significant length of time.
If you want to save a buck you can buy just the boot and replace it. Costs as little as $8, but it's a messy job.
The tape wont work - it cant stand up to the flexing for any significant length of time.
If you want to save a buck you can buy just the boot and replace it. Costs as little as $8, but it's a messy job.
Mooseman
Moderator
paul2005tb
Member
I have seen youtube videos of guys using standard inner tube patch kits with the vulcanizing cement. Others are advocating for the use "shoe-goo" on cv boot repairs. Im going to try one of these solutions.
The likelihood of success probably depends on where you're going to try a repair. If it's in a high flex area then no repair will last.
Good luck!
Good luck!
paul2005tb
Member
Well, I first tried the inner tube patch. I prepped the surface meticulously, the patch wouldn't hold. It just seemed the boot was not pure rubber and that was the problem. I then took patch off, started again with cleaning, acetone was key. Then used "shoe goo" . It looks good. I'll know in a few months. I'll order a new boot and will be ready. I'd like to get a year out of the shoe goo repair
paul2005tb
Member
I hear you, I did not feel great about the shoegoo solution but it is a remarkable substance. It is very sticky, it stuck to the boot very well and when it cured, it was very flexible, it was like rubber. I will find out how good a solution it is if it holds through winter. If it can survive a New England winter then it is a great way to fix a torn CV boot anywhere on the planet.