Edmunds dealer partner, Bayway Leasing, is now offering transparent lease deals via these forums. Click here to see the latest vehicles!
Popular New Cars
Popular Used Sedans
Popular Used SUVs
Popular Used Pickup Trucks
Popular Used Hatchbacks
Popular Used Minivans
Popular Used Coupes
Popular Used Wagons
Comments
Today I'll stop by the Chevy dealer (parts dept) to see if I can pick-up any additional info regarding fuses and their location. As I previously stated I only found 3 fuses relating to 4WD system (4WD, TREC, B/U LP) but am still trying to find out whether I actually have a fuse for the ATC or a 4 x 4 Module. For all I know the fuse labeled 4WD could be the ATC (Auto Transfer Case).
If anyone has any other ideas, please advise.
Thanks for all the comments and suggestions so far.
A skilled (ASE certified) mechanic installed it for me in about one hour's time and the 4WD system now seems to be functioning correctly. I notice that shifting occurs more quickly.
Cautions:
Check and double check your transfer case option code.
If you do get a part, make sure it's the right one.
Don't substitute a bigger ATC fuse, you could have fire in the wire harness.
My opinion: I avoid using the Automatic 4WD as I think it engages harshly.
So far, so good. Best of luck to you all.
NIKT
and
I purchased a Haynes Repair Manual and a friend of mine ( with wrenching experience) came over on Saturday and we diagnosed the 4WD system from the automatic pushbutton to the Acuator/encoder motor at the transfer case to the front axle shift motor (acuator).
Turns out that it was a bad front axle shift motor which is probably the easiest item on the 4WD system to change out The unit screws right into the axle tube..
Thanks again to all of you who made suggestions and shared their issues.
Regards,
Tony
Good job! Please tell me the title or publication number of the Haynes manual you used.
As my Tahoe ages, it may need more repairs, so a manual will be a big help.
Good luck,
NIKT
Thanks.
The Haynes Manual ( # 24066) I bought covers Chevy Silverado, GMC Sieera 1999- 2006. it also covers Suburban, Tahoe, Yukon, Denali, Avalanche, etc
You could probaly check it out on-line or at your local Napa Auto Shop (or similar)
Take care.
I guess I'm now "kind of a wrench guy"
Disclaimer: Although I got my Tahoe 4WD working, I am NOT a 4WD drive guru.
But, I do want to help. Based on my experience watching the mechanic install the shift (encoder) motor onto my transfer case, and my taking apart the faulty shift motor unit, here is my take on the shifting process and what I suggest:
The shifter motor bolts onto the transfer case and the actual connection is a short shaft that comes from the transfer case that mates with shifter motor. The shifter motor is controlled by the Transmission Control Module (TCM). when you call for 2WD, 4WD, etc., the TCM tells the shifter motor to rotate that stub shaft to engage couplings, etc. that I imagine control splined shift collars, etc. The TCM does two things: It electrically releases a spring-applied brake and spins the shift motor that turns the stub shaft to the selected function (2WD HI or OR 4wd HI, etc.). A rotary position sensor tells the TCM when the correct function has been selected and the motor stops and the little spring-applied brake holds the shaft in the right place (Drive function).
Now, the new shift motor comes with a plastic tab holding it in Neutral position. The owner's manual tells how to put the transfer case in Neutral so the new shifter motor can be installed, but the mechanic that fixed my Tahoe simply took a wrench and turned the stub shaft until he reached Neutral, and then installed the new shifter motor unit.
I conclude from my experiences noted above, that you could remove the shifter motor, rotate the stub shaft to 2WD HI, and drive away. A BIG CAUTION here though; you must find away to lock the shaft in 2WD HI, because you don't have the little brake in the (now disconnected) shift motor unit to hold the shaft in position. Also, you will have to perform a short driving test to assure that have 2WD. If you are electrically and mechanically handy, or have a friend who is, you might be able to energize the brake and motor from an external 12 Volt source to do the shifting. Just don't energize the motor until you energize the brake to release it.
In short, it is possible to get back to 2WD, but please be careful to lock the shaft.
I hope all this helps.
Best of luck to you and please let us all know how you make out on this fix.
NIKT
Just dropped it off at the local Chevy Dealer and I am impatiently waiting for the call. Based on the symptoms read in this thread and what I have described on my Tahoe, does it sound like the motors were locked up and now they just seized, causing the over-current?
Speaking not as an expert, it sounds like you diagnosed the problem correctly. I'm guessing the dealer may have to scan the TCC for trouble codes to see what else, if anything, may need repair. Your Tahoe is like my '99 Tahoe, and after 10-11 years, "stuff" just wears out.
Good luck on resolving you 4WD problem.
nikt
Thanks to all the thread posting out there.
Any information on if this is happening generally or how it has been handled would be appreciated. Thanks,
There's another edmunds forum on sub/tahoe with many posts on this subject.
It's not as expensive repair as you may think.
Sorry I can't help.
Now it seems to be stuck in either 2x2 or 4x4, but the truck doesn't seem to accelerate properly. Might this be the issue? any help would be appreciated.
Then one day the tramsmission went "CLUNK" and the light went from "AUTO" to 4 wheel "HIGH" without any request from the driver. I reset the "AUTO" position on the switch and there was noise and then no lights on the control panel. The lights stayed off for 6 months and in that time we relocated to south Texas.
About three weeks ago the light for 4 wheel "HIGH came back own and I reset it for "AUTO" with no results, so, I tried 2 wheel and it came on properly. My wife drove the vehicle for about two weeks during which the lights switched from one to another and back again...during that two weeks, we had it at the dealer TWICE and they sent us away with an appointment to return at a later date...no problem..right?? WRONG ANSWER!!!!!!
On Friday 5/28 the Transfer Case errupted and the case was cracked beyond repair. The symtoms never raised a red flag with the service department who said it only need a $250 part and reprogram of the control computer.
Believe it or not it still drove normally after the explosion, albeit, with some tinking sounds at low speed. The vehicle is hospitalized at present and we do not have a prognosis and are not sure if our extended warranty will cover this repair.
The rental suv is nice and we are holding our breath...I will post additionally when the damage estimate comes in..
LESSONS LEARNED>>>>so far.
1. Never ignore the absense of an indicator light..have it checked.
2. The service department may NOT always steer you correctly.
3. The information here is more reliable than my dealerships service dept.
I am from GM Customer Service. Please keep me posted on how everything goes at the dealership. Thank you,
Mariah GM Customer Service
Hello and Thank You for your interest in my issue.
The Tahoe came thru the service event with a Rebuilt Transfer Case that was installed due failure of the in-service part @ the upper gear which ruptured the rear housing cover, there was also a shaft that was replaced as part of this portion of the repair. My wife was @ 65 to 70 mph when the transfer case attempted to engage and this damage occured. The cost for this repair was $2700 (approx.)..It appeared that the failure was the result of the attempted engagement of the 4x4 drive unit as a result of the malfunctioning selector switch, not sure that it was not caused by the electrical sequencing module that I have read about in post.
Financially, this was an absolute nightmare...our 100,000 warranty was found to be a 3 yr./36,000 mile warranty and expired @ 78,400 miles...OOOPPS.
The other repairs, tachometer failure, climate control computer and the ever present clunky steering column added an additional $700 to the invoice. The climate control problem is still present as is the steering column clunk, although somewhat better. Altogether, $3647 and change, out of pocket.
My background is in aircraft maintenance for over 35 yrs. and I know that mechanical things wear out and need service periodically, had I been advised that this kind of failure was possible/probable based on the symtoms that the service department had reported on the previous visits in the weeks leading up to this event I could and would have taken steps to leave the vehicle for repairs prior to this event.
The family loves the Tahoe, previously we had three Suburbans, a C3500 4 door truck and a C1500 regular cab truck. I restored a 1961 Apache 10 truck and have had several ragged out Chevy trucks over the years.
I wish I had seen this coming.
Lessons Learned:
(1) Loving your vehicle does not make it bulletproof, always get the maintenance done when the problem is first encountered....mechanical problems are not self-healing.
(2) Many maintenance issues do not exit in a vacuum, get all the current information that is available thru internet channels, the information is up to date and in my opinion more reliable than some service providers will give.
(3) EXTENDED WARRANTY...Check yours for relevance, coverages and deductibles. I blew this one "BIG TIME".
Respectfully,
Glenn Hayes
La Vernia, Texas
Did you tell the dealership that the steering clunk is present and the climate control problem is still there? I am glad the rest of the concerns have been taken care of. Thank you for letting me know how everything went. If you have any other questions please let me know. Thank you,
Mariah GM Customer Service
The dealer couldn't get any codes but had a tech drive my truck home & after sitting all night, it acted up on the tech driving back to dealer. The dealer replaced the transfer case module to the tune of over $500. Repeated the same thing w/o problem replicating. I took my truck thinking all is well. HA HA.
5 days later, I found truck in Auto 4WD & put into 2H using buttons immediately, thinking I might have hit it by accident. That night, turned on truck & in neutral. So $500 fix didn't work. I found that restarting truck would re set to 2H.
12 hours later, my truck turns on in 4L. Restarting does nothing on 4 tries. Drove it as no choice to get to appt at 25mph on interstate. Of course on way to dealer, it is in 2H. Dealer finds no codes ( of course). Tech drives home & acts up next morning. Switch is replaced. Problem is still replicated by tech 24 hours later. Dealer does work on wires next. Problem is replicated by tech 24 hours later.
GM was apparently called & sensor was replaced with no replication on friday but dealer wanted to make sure. Tech drove it home w/o replication last night.
I was told that I could get my truck at 7am today and knowing I had to be at work at 8am, I was there at 7:15am. I had called dealer last night from work to notify them I would be in very early & needed my truck ready to jet after I paid for the parts. Imagine my luck when service rep told cashier and courtesy guy that "I can wait" as guy needed to pull cars into service bay. I couldn't wait to get my truck, so I went to look for it & didn't succeed. Neither did 2 other people for 20 minutes.
So I am late to work, out $500 for the module, 2 days of rental car last week, switch and sensor cost too. I am thinking of visiting service mgr for the unnecessary replacement module since everything done but 1 didn't fix problem.
Other family members have 3 suburbans from 1999 to 2008 and 1 tahoe 2009 -all have 4x4 & never had this problem.
I am having the same "service 4 wd" light on the display. 2004 Tahoe Z71. did you replace the transmission motor switch yourself or did GM do it? If yourself, is it simple enough to do? Where did you get the part. can you please give me some pointers on replacement.
My story, just in case your interested:
Had the oxygen sensors replaced and, two days later going down the freeway... rip, thud, thud, thud, rip, bam! and rolled to a stop. The sensor wiring harness was wound around the front drive shaft. Along with the sensor harness was the transmission wiring harness as well as the transmission linkage. Also ripped out the linkage bracket.
After a week in the shop 300 miles from home, the harnesses, linkage and bracket were replaced with a mixture of new and scrapyard parts. No... I didn't pay $2300 for a new transmission harness... lol.
When I picked it up after turning in the rental, I found that the 4 wheel drive did not work. Lights on the indicators worked somewhat and, when anything was pushed, "neutral" illuminated... but no response down below. Drove home in 2 wheel thinking I'd work on it more later. Yes, I could have held the shop responsible for missing it but, frankly, I'd had enough for the time being. Remember... 300 miles from home.
Kudos to this forum. May I say again... KUDOS TO THIS FORUM AND ALL WHO POST! Finally found the 20 amp T Case fuse, replaced it (it was blown, of course) and as nikt said, even though the keys were nowhere near the ignition, I heard the click of the transfer case. Started it up and all is well!
thanks for any help
the lights on the dash seem to work properly, they flash for a moment then stay lit, but the vehicle never engages into 4 wheel drive, any answers ?
Reader's Digest version: Heard a rattle up front, and could not figure out what it was. This happened for about a month, and then my transfer case started to neutralize on it's own. Took it to a local transmission shop here in Tucson, and they could not figure out what was wrong. Everything was MECHANICALLY perfect with the transfer case. Took it to O'Rielly Chevrolet here in Tucson, they tore my transfer case apart, and told me that I had the WRONG PARTS in my transfer case. Excuse me? How the hell could I have the wrong parts in my transfer case? I even have this DOCUMENTED!!! Needless to say, I ended up paying $2500+ for a brand new transfer case.
Fast forward a couple of weeks later, and I came across the documents below. Turns out the rattle that I heard was from the transfer case main shaft and the inner clutch hub assembly. The early designs of our transfer case came with a "slip fit" design for these two parts. The parts were rattling, CAUSING ENCODER MOTOR FAILURE! The encoder motor failed, causing my transfer case to neutralize itself when simply driving down the road in 2wd.
The following documents go on to explain how the Chevrolet techs are to replace the two parts with "the inner clutch hub and shaft, which will have a PRESS FIT design and eliminate the rattle condition."
Common sense tells me that the tech that tore apart my transfer case at O'Rielly's looked at my ORIGINAL SLIP FIT clutch hub and shaft, compared it to pictures/documents of the newer PRESS FIT clutch hub and shaft, and deduced that I had the wrong parts in my transfer case, and thus that must be the problem. All along, turns out that it was because of a DESIGN FLAW in the original transfer case that caused the encoder motor to fail, causing neutralization of the transfer case, costing me over $2500.
I got nowhere with the dealership, nowhere with GM Customer Care (yes, I do have my GM Incident Number - let's see if anyone from GM Customer Care "cares"), and I promise to God that this will be the last GM product I EVER BUY.
Documents:
Also search on Google for: "DTC C0327 #PIP3480K"
NHTSA Item Number : 10017299
NHTSA Item Number: 10018926
NHTSA Item Number: 10018607
Service Bulletin Number : 3665
Service Bulletin Number: 3480A
Document ID: 1884845
thanks
boelter
Being an electrician for 40 years, I would definately say you have a direct short some where. Try and disconnect each part one at a time and meter to ground to find the problem. The side sliding door on my mini van quit working, and luckily I noticed the sparks coming from the traveling wire harness at the bottom of the door.....the insulation they used just deteriated.
Steve-O
Good luck!!!