4wd Chevy problems

[gregintenn]

Between you all here, somebody knows almost everything, so I'm hoping I can tap that knowledge a bit.

I have an 02 Silverado. Last winter, I put it in 4wd, and the front wheels didn't turn. The light came on, I could hear the actuator work, but no dice.

I've replaced the transfer case actuator, and the selector in the dash. I've also checked the fuses. These things, I understand, are the most common problems.

Since the front drive shaft doesn't turn, I'm ruling out the front differential, and focusing on the differential. I've about run out of ideas except for the $150 control module, or pulling the transfer case, splitting it open, and taking a peek inside.

Any help would be greatly appreciated.

 

[chief38]

My suggestion is to pay a visit to the best Chevy Dealer in Town. People who see these Trucks on a daily basis should be quite familiar with common problems - if this is a common one. In any event, probably the best place to start. You can always say no. The Dealer might be more expensive, but you are gonna save in the frustration and longevity of the problem.

 

[twodog max]

A dealer will be very expensive. I would look around your locale for a transmission shop that does 4WD drivetrain repair and try that. I had a Chevy years ago that had 4WD trouble and got mine fixed that way and for far, far less than a dealer would have charged.

Back when I was working we often were required by the employer to use dealer repair shops on work vehicles. They are no guarantee of perfect service.

 

[gregintenn]

I've been reading about various problems on the internet, and haven't really found one exactly like mine. Everything seems to be working correctly, and no warning lights. Perhaps the transfer case is bad? Is there any way to check it without taking it out and tearing it apart?

 

[4barrel]

Put it in neutral & jack the front up & make sure the front drive shaft turns. No need to crank. With the key on get someone to hit the 4 wheel switch while you feel of the front end. If it clicks it should lock. Try hi & low. Spider gear? Under the battery box there should be some vacuum hoses & wires. You may have to remove the battery box to inspect.

 

[307-Niner]

Between you all here, somebody knows almost everything, so I'm hoping I can tap that knowledge a bit.

I have an 02 Silverado. Last winter, I put it in 4wd, and the front wheels didn't turn. The light came on, I could hear the actuator work, but no dice.

I've replaced the transfer case actuator, and the selector in the dash. I've also checked the fuses. These things, I understand, are the most common problems.

Since the front drive shaft doesn't turn, I'm ruling out the front differential, and focusing on the differential. I've about run out of ideas except for the $150 control module, or pulling the transfer case, splitting it open, and taking a peek inside.

Any help would be greatly appreciated.

I worked in the GM dealership service departments for 14 years, in the land of 4x4 trucks (Alaska). I have a few questions before I can help.

1) Do you get a "Service 4x4" warning on your instrument cluster message center?

2) What are your truck's RPO "N" codes? These are on a sticker in your glove box. I just need the codes beginning with "N".

3) Does your truck have 4 exact matching tires (brand, size, load rating, tread design, and tread depth)? Has it ever (to your knowledge) had mis-matched tires?

4) When you push the 4x4 button on your switch, does it blink several times & then go back to 2WD? Or does it look normal & light up the 4x4 button?

5) Do you have access to a scan tool with capability of reading the TCCM (transfer case control module). Generic code readers usually cannot.

 

[gregintenn]

I worked in the GM dealership service departments for 14 years, in the land of 4x4 trucks (Alaska). I have a few questions before I can help.

1) Do you get a "Service 4x4" warning on your instrument cluster message center?

2) What are your truck's RPO "N" codes? These are on a sticker in your glove box. I just need the codes beginning with "N".

3) Does your truck have 4 exact matching tires (brand, size, load rating, tread design, and tread depth)? Has it ever (to your knowledge) had mis-matched tires?

4) When you push the 4x4 button on your switch, does it blink several times & then go back to 2WD? Or does it look normal & light up the 4x4 button?

5) Do you have access to a scan tool with capability of reading the TCCM (transfer case control module). Generic code readers usually cannot.

1)No
2)NGO
NP5
NP8
N22
3)Yes and No
4)Appears to work correctly.
5)I do not.

 

[johngalt]

In my 97, the front output shaft was frozen. I think it has a telescope mechanism that engages when switching to 4 wheel drive. I don't know if your generation uses the same system.

 

[arjay]

Are you sure that the auto hubs are engaging?

 

[gregintenn]

In my 97, the front output shaft was frozen. I think it has a telescope mechanism that engages when switching to 4 wheel drive. I don't know if your generation uses the same system.

I'm not sure. I think the trucks changed in 98.

What was the fix for that?

 

[johngalt]

I'm not sure. I think the trucks changed in 98.

What was the fix for that?

New output shaft. I forget the cost, I think a few $100.

 

[gregintenn]

Are you sure that the auto hubs are engaging?

No locking hubs. The axles engage/disengage inside the front differential. Anyway, if the front driveshaft isn't turning, nothing's going to happen up there.

 

[307-Niner]

1)No
2)NGO
NP5
NP8
N22
3)Yes and No
4)Appears to work correctly.
5)I do not.

Let's troubleshoot this a little bit. I believe you said you found & checked both of the fuses. So next, we need to determine of your problem is in the transfer case or front differential. We need to see if the front differential actuator is locking when it's supposed to, and we need to see that the transfer case is shifting.

Best way is to put the truck on 4 jackstands. With the key "ON", engine "OFF", have somebody shift back & forth from 2 to 4 wheel drive. You should hear the transfer case shift motor move, and feel it thunk with your hand on it. Check the front axle actuator the same way, but you'll probably only hear it move(no thunk).

Next, leave the switch in 4x4. Turn one of the front wheels & hold the other front wheel stationary. If the front axle actuator is engaged, your front driveline will spin. If not, we have an electrical problem with the front differential actuator, or an internal mechanical problem.

If the front diff checks out okay, and you can hear & feel the transfer case shift motor working, then you likely have an internal transfer case problem. Your transfer case has a clutch pack (similar to auto transmission clutch packs) that drives your front driveline. If it's shifting, but not powering the front wheels, that clutch pack may be toast.

If you have any questions along the way, send me a PM.

 

[THE PILGRIM]

A few years ago I happened to see an electric mechanism laying in a mechanic's work bench.
It looked like a tinker-toy piece of junk to me.
He laughed when I asked him what it was.
It turned out to be the actuating device which put a Ford Bronco II transfer case into 4 wheel.
I like the transfer lever sticking out of the floor.
Probably all long gone, but some of us old guys still remember them.

 

[gregintenn]

Let's troubleshoot this a little bit. I believe you said you found & checked both of the fuses. So next, we need to determine of your problem is in the transfer case or front differential. We need to see if the front differential actuator is locking when it's supposed to, and we need to see that the transfer case is shifting.

Best way is to put the truck on 4 jackstands. With the key "ON", engine "OFF", have somebody shift back & forth from 2 to 4 wheel drive. You should hear the transfer case shift motor move, and feel it thunk with your hand on it. Check the front axle actuator the same way, but you'll probably only hear it move(no thunk).

Next, leave the switch in 4x4. Turn one of the front wheels & hold the other front wheel stationary. If the front axle actuator is engaged, your front driveline will spin. If not, we have an electrical problem with the front differential actuator, or an internal mechanical problem.

If the front diff checks out okay, and you can hear & feel the transfer case shift motor working, then you likely have an internal transfer case problem. Your transfer case has a clutch pack (similar to auto transmission clutch packs) that drives your front driveline. If it's shifting, but not powering the front wheels, that clutch pack may be toast.

If you have any questions along the way, send me a PM.

Thanks a lot. It is definitely the transfer case. I can put it on jack stands, put it in 4 high or 4 low, transmission in drive, and the rear wheels turn, but the front driveshaft doesn't. This eliminates the differential, right?

 

[gregintenn]

A few years ago I happened to see an electric mechanism laying in a mechanic's work bench.
It looked like a tinker-toy piece of junk to me.
He laughed when I asked him what it was.
It turned out to be the actuating device which put a Ford Bronco II transfer case into 4 wheel.
I like the transfer lever sticking out of the floor.
Probably all long gone, but some of us old guys still remember them.

Yeah...I never once had a problem with a manually shifted transfer case, nor a straight front axle.

 

[BigBill]

Yeah...I never once had a problem with a manually shifted transfer case, nor a straight front axle.

That's all I ever owned was manually shifted transfer case and straight front driving axle. While my building 4x4 truck days are over. I still have a jeep. Older.

 

[307-Niner]

Thanks a lot. It is definitely the transfer case. I can put it on jack stands, put it in 4 high or 4 low, transmission in drive, and the rear wheels turn, but the front driveshaft doesn't. This eliminates the differential, right?

I would recommend verifying that the front differential is actually locking when it's supposed to. And verify that the transfer case encoder motor is shifting. These are controlled by the TCCM, and you may have an electrical problem instead of a mechanical problem. If these are proven to be working correctly, the next step is a transfer case teardown, probably will need clutch packs.

Hope this helps.

 

[model70hunter]

Question, what is the fluid level in the xfer case. And does it have the correct fluid?

It sounds like some of the old posi packs and if the right oil was not used it may be bad clutches and clutches do wear out.

The mechanic gives good advice.

 

[gregintenn]

I would recommend verifying that the front differential is actually locking when it's supposed to. And verify that the transfer case encoder motor is shifting. These are controlled by the TCCM, and you may have an electrical problem instead of a mechanical problem. If these are proven to be working correctly, the next step is a transfer case teardown, probably will need clutch packs.

Hope this helps.

This helps a lot! Thanks again.

A rebuild kit isn't very expensive. I guess I'll wait for a free weekend and tear into it. I just hated to take it apart and find there wasn't anything wrong in there.

 

[gregintenn]

The other option would be to buy a rebuilt one. More money, but a much easier job, and very little down time for the truck. Whadda think?

 

[THE PILGRIM]

The other option would be to buy a rebuilt one. More money, but a much easier job, and very little down time for the truck. Whadda think?

I recommend you follow the advice of 307- Niner and run down every electrical problem possibility before you tear into that transfer case.

 

[Nevada Ed]

All these new fandangled 4x4 rigs...............
Good luck.

Cut my teeth on this.

 

[smokindog]

I have a slightly different issue on my '97 GMC Z71. Push button 4WD Hi/Lo. It sometimes won't disengage. The solution is to select 2WD and drive in reverse!!!! Been like this for more than 10 years I do NOT use 4WD very often, like in rarely...... I had to drag a rather large rock from the creek side yesterday so I used the "stump puller" 4WD lo and, you guessed it, needed to drive in "R" to get back to 2WD!!!

 

[model70hunter]

All these new fandangled 4x4 rigs...............
Good luck.

Cut my teeth on this.

Ed ya got 2 likes from me on this one. Is it a WW 2 or an early post war copy?

My first of many was an M38 cherry National Guard surplus.

 

[CustomChevyGuy]

If you want to try to find a resource to guide yourself by, then check out the fullsizechevy.com forum. There are tons of experienced owners for about every issue you could think of. I've been a member over there since before I bought my truck.

I've got the same username over there as well..

 

[JcMack]

I have a slightly different issue on my '97 GMC Z71. Push button 4WD Hi/Lo. It sometimes won't disengage. The solution is to select 2WD and drive in reverse!!!! Been like this for more than 10 years I do NOT use 4WD very often, like in rarely...... I had to drag a rather large rock from the creek side yesterday so I used the "stump puller" 4WD lo and, you guessed it, needed to drive in "R" to get back to 2WD!!!

The only 4WD PU's I've owned were manual trans, manual X fer case, and manual hubs. With an auto trans and hubs don't you have to drive in reverse to disengage the hubs as part of normal procedure to return to 2WD?

 

[M&P340]

There should be a collar that slides when you engage 4x4. This will be on one front axle or the other. Those can go bad. I don't think new trucks used auto locking hubs anymore.

 

[gregintenn]

Thanks for the help everybody! I ordered a rebuilt transfer case on ebay. Put it in last weekend, and I'm back in 4 wheeling business!!!

 

[M294Ever]

Thanks for the help everybody! I ordered a rebuilt transfer case on ebay. Put it in last weekend, and I'm back in 4 wheeling business!!!

Now rebuild yours, sell it on ebay, and your back in 4 wheelin business for free! ( and maybe even a profit!)