4wd won’t engage

otter44

Newbie
Original poster
Nov 23, 2022
1
RR#1 Elmwood On
My 2004 envoy 4wd won’t engage.I can hear the transfer case motor running but still stays in 2nd. I have a 4 wire plug on front axle actuator motor, a brown a blac with white tracer an all black and a green wire.I can’t locate a wiring diagram to figure out what does what. Any help would be appreciated. Thanks.
 

Eric04

Active Member
Dec 3, 2014
376
West Michigan
My 2004 envoy 4wd won’t engage.I can hear the transfer case motor running but still stays in 2nd. I have a 4 wire plug on front axle actuator motor, a brown a blac with white tracer an all black and a green wire.I can’t locate a wiring diagram to figure out what does what. Any help would be appreciated. Thanks.
Manuals:

Good thread on 4WD troubleshooting:
 
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flyboy2610

Active Member
Aug 24, 2021
325
Lincoln, Ne.
If you do wind up needing to replace the front axle disconnect, do not attempt to to simply pry it out of the hole in the oil pan! It's almost guaranteed to break off the inner part of the disconnect housing in the oil pan, and then the job just got a lot more complicated!
The disconnect tends to get corrosion bonded to the oil pan. After removing the CV axle, and the 4 bolts holding the disconnect to the oil pan (don't remove the 4 holding the two halves of the disconnect housing together), remove the splash shield under the oil pan. This will give you a clear view of the bottom of the disconnect. Take a brass or ball-peen hammer and lightly tap one side of the disconnect upwards. You won't be able to go too far because there is a bulge on the disconnect (where the spring is) which fits into a hole in the oil pan.
Then tap on the other side. The idea is to just break that corrosion bond. Once the disconnect will freely pivot in the oil pan, tap it outwards towards the fender just a bit, then tap it back in. Tap it out a little farther, then back in. Repeat the process until the disconnect is free.
I had to replace the one one my '04 TB EXT recently. I bought the Dorman (yes, Dorman) unit from Rock Auto. Cost me about $500 with tax and shipping.
The Dorman unit has a forged shifter fork, as compared to the cast fork in a stock unit, and also has 3 wear pads as compared to 2. The disconnect is rebuildable https://offroadtb.com/4wd-disconnect-rebuild/
so rebuilding your current unit is an option if you have another vehicle to drive while you wait for parts. I'm rebuilding the one I took off my TB. I don't have a spare vehicle, so I had it buy a new disconnect in the meantime. To find parts I just copied the parts numbers I needed from the list in the rebuild article and searched for them on eBay. I did buy the new Dorman fork, though. https://www.ebay.com/itm/2037159873...=0&customid=link&campid=&toolid=20001&mkevt=1
Another option is to purchase the sleeve that the AWD vehicles use. This will permanently lock the CV axle and the intermediate shaft together, and the front end will function like a solid axle vehicle with an open differential. Only the transfer case will shift the Envoy into or out of 4WD. https://www.ebay.com/itm/4016962412...=0&customid=link&campid=&toolid=20001&mkevt=1
Hope this helps you.
 

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