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2004 4 wheel drive issue

M

Mwinte

New Member
Joined
May 11, 2022
Messages
3
I've searched and can't find my issue. 2004 base avalanche 1500 (new to me), occasionally the service wd warning will come on. When it does my 4wd (or auto 4wd) light will not light. eventually I can get it to engage but sometimes on auto it will engage, work fine, then the light will go off (not sure if it reverts to 2wd or not). I know it's never a good idea to throw parts at something without totally knowing the problem BUT my scanners don't do trans codes (and I live in a rather rural area). I am planning on checking and cleaning the xfer case grounds (and maybe adding one) . I also plan on replacing the encoder motor ring. What else would be a likely problem area??? I figure grounds and ring are a common fault and worst case I'm out a little time and money BUT have a better baseline of the 4wd service done on the truck.
 
Those are the 2 most common failures that you mentioned. Could also be the switch itself. Best is to plug in and see what codes it has.

Some info and pics on the first page about the t-case.

Got some goodies in the mail today

So I've only had my Avalanche for about 3 weeks now but one of the first priority items is getting the 4WD fixed. The codes point to the encoder ring so I picked up an AC Delco. Also did a trans filter change last weekend. Still need to change the plugs. I know most recommend the AC Delco or...
www.chevyavalanchefanclub.com www.chevyavalanchefanclub.com
 
fuses, corroded connectors, encoder motor, TCCM in that order. Honestly, switches are often replaced (because they are cheap) but rarely ever go bad. 4WD is VERY difficult to diagnose without a capable scanner and it's not transmission codes, it's 4WD codes stored in the TCCM that need read to get you to the correct factory diagnostic chart. With a Tech 2 or other capable scanner, it's super easy.
 
Just an update. I finally got around to taking some time to fix this issue. I cleaned the grounds (no change). I pulled the switch (I had seen a you tube repair "re-floating" the solder points) I "re-floated" mine with a heat gun (VERY BADDLY I might add) and it made a difference in how the 4wd acted. I replaced the switch and the 4wd has been working flawlessly for about 3 weeks. I still plan on doing the encoder motor ring but I feel my issue has been resolved. For 10 minutes pulling a switch and "re-floating" connections to assist in troubleshooting I feel it was time well spent. Funny thing is (I know a scanner would have told this) the switch was the last ting that I would have thought was the problem.
 
Mwinte said:
Just an update. I finally got around to taking some time to fix this issue. I cleaned the grounds (no change). I pulled the switch (I had seen a you tube repair "re-floating" the solder points) I "re-floated" mine with a heat gun (VERY BADDLY I might add) and it made a difference in how the 4wd acted. I replaced the switch and the 4wd has been working flawlessly for about 3 weeks. I still plan on doing the encoder motor ring but I feel my issue has been resolved. For 10 minutes pulling a switch and "re-floating" connections to assist in troubleshooting I feel it was time well spent. Funny thing is (I know a scanner would have told this) the switch was the last ting that I would have thought was the problem.
Click to expand...
I had similar symptoms last fall (04 1500 Z71). replaced the switch (looks out of place it is so nice and shiney) still works like a champ
 
Funny thing is my (old) switch looked to be fairly new (but 18 dollar part so what can you expect I guess).
 
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