Help With GM 4x4(Push Button)((99-06)) Transfer Case Please.

Arnold · December 30, 2012, 11:10:11 AM

Also has Auto 4x4
My 01 Suburban got stuck. The back wheels were spinning. The fronts
were not. This happened in 4x4 High,Low,and Auto. I did some homework and heard/read that this cannot happen. Well..it can..and does. Some say it is a direct drive transfer case. Well..no it is not. There is a clutch pack that applies pressure to the front output shaft. The pressure is controlled by the pressure applied to it by the shift control motor.That part is computer controlled..by the seperate 4x4 computer.

Is there ANY way of testing one of these??? Breakaway torque of the front driveshaft maybe??

When it was stuck..there was quite a load on the engine..the back tires were barely spinning..but even when spun a fair bit..no wheel spin from the front. There was quite a bit of work being done by the front wheels as when it was shifted into 2wd the thing would spin the rear wheels effortlessly. When shifted into 4wd there was some serious grip!. Just not enough to spin the front wheels OR get me out. GRRRRR

I do have a very heavy commercial plow on it. (Police 3/4 ton Suburban that is extreme HD 3/4 ton) This thing also has 380 HP factory.
I took it to a friends garage who knows quite a bit about these things.
He tested it and said there was plenty of power(no kidding) and plenty of grip.
I was plowing snow at the time and working the truck..though not that bad. He said I may have overheated the transfer case fluid and that might have caused this. He checked it and it was burnt and looked awful so he flushed it. He said that might have been the problem.He also said it might have had the wrong fluid in it?
He also said that the clutch..may be on the way out..or the shift motor(inadequate pressure applied to the cliutch) OR something wrong in the seperate 4x4 computer.

I really need to test..or fix this thing. Not really interested in getting it stuck again to find out.

My friends garage said it also could have been caused by not using all the ranges in the transfer case..especially the auto feature for a long time.
He said they can get stuff stuck to the solenoids and not fully engage..or allow the shift motor to disengage them. He said to use all the ranges every now and again..drive it for a while.

This truck also has a G80 rear locker that was just acting stupid. Refusing to lock..spinning one wheel..or the other..engaging really rough.
I changed the fluid.Somehow? It was drastically overfilled?? and the fluid was like varsol and really,really bad. After I changed that the rear end works perfect now!! My friends garage said that something like that can drive the 4x4 computer mental and there might be some "adaptive learning program" in there that can take a while to re-adjust itself.

Sorry for the long post..I am pretty lost with this thing. I live in the boonies..and either you have working 4x4 or you fix it.

Any help is greatly apprecitated!!!

Thanks..

wayne petty · December 30, 2012, 12:15:29 PM

http://www.extendedgmwarranty.com/owners-manual/chevrolet/2001-Chevrolet-Suburban.pdf

page 7-25 shows the proper fluid for the automatic transfer case..

AutomaticTransfer Case
AUTO-TRAK II Fluid
(GM Part No. 12378508).

if this is similar to the other all wheel drive fluids used in gm cars and trucks.. it usually requires several changes within a few days with some test drives to work the clean fluid between the clutches...

i don't know the procedure for the transfer case... but it can be found below... i will look around for more info...

so stay tuned...

http://www.eautorepair.net

http://www.alldatadiy.com

i don't know exactly which model you have... but this will be a shortcut to the proper selector to look at TSB titles

http://alldatadiy.com/TSB/0111_mo.html

this video i DON"T think is your transfer case...

this might also help its about changing the transfer case encoder sensor... i have heard about this.. this counts the amount of position from fully applied and partially applied and could be your exact issue... as the PCM does not know how tight the clutches have been engaged to prevent slippage...

i hope this helps...

there is also a warning from another site that says to be careful when positioning the drain pan to catch the fluid.. as its very thin and can shoot backwards several feet..

Arnold · December 30, 2012, 04:24:27 PM

Thanks very much Wayne!

Yes..Auto Trac II fluid went back in.

It is a 246 case and 4L80.

I am in the process of driving it..using all the ranges.. to get the fluid circulated everywhere. Another flush/change is coming too

I don't know if the encoder sensor and encoder motor are seperate.

Thanks for the links!

wayne petty · December 30, 2012, 04:40:12 PM

watch the second video...

its 12 minutes but it will save you HOURS and hundreds of dollars...

the encoder is inside the motor assembly.. some techs will ONLY replace expensive parts... as they are on commission.

some techs will only replace expensive parts because they don't know how to repair the individual components..

please use the alldatadiy link and check for TSBs..

also check for codes with an advanced scan tool... as its probably not going to show up with a generic scan tool

i do try... i have even fixed a few of the yugos around here.. don't need a warmed back window when wearing sun screen..

Arnold · January 02, 2013, 10:41:21 AM

Quote from: "wayne petty"watch the second video...

its 12 minutes but it will save you HOURS and hundreds of dollars...

the encoder is inside the motor assembly.. some techs will ONLY replace expensive parts... as they are on commission.

some techs will only replace expensive parts because they don't know how to repair the individual components..

please use the alldatadiy link and check for TSBs..

also check for codes with an advanced scan tool... as its probably not going to show up with a generic scan tool

i do try... i have even fixed a few of the yugos around here.. don't need a warmed back window when wearing sun screen..

I have done a fair bit of research about this.

I MAY have found the problem :evil: When I greased the front driveshaft recently..I had to turn it by hand..as in YA. DUH. How else can I grease the joints??Well..apparently that is a
BIG NO NO! This has happened to others! Turn the front shaft by hand and that can really throws things off can set off the "service 4x4 light".
Because: When it is shifted into 4wd the "whatever" looks for the position of the front shaft. IF it does not find it where it is supposed to be.
Or was. Then it has to "look" for it..and then the "adaptive learning code" takes effect.

How dare I move it myself

I was near a huge new car dealer and asked them how they greased front 4x4 driveshaft u-joints WITHOUT turning the shaft by hand.
They said the same way they grease the backs! They do it over a lube bay. Shift into 4x4. One person drives it over until it is in position. Grease. Move truck. Do it again.

Think I need some egg nog..or grease. :oops:

wayne petty · January 02, 2013, 10:52:13 AM

thats totally bizzare

the rotary encoder counts the steps of the motor position to see how far extended it is... there probably is a shaft position sensor.. so it knows when it is slipping...

i guess i will have to dig deeper if it still happening..

i will look around tonight and see if i can find a factory service manual for it..

Arnold · January 02, 2013, 11:11:11 AM

Quote from: "wayne petty"thats totally bizzare

the rotary encoder counts the steps of the motor position to see how far extended it is... there probably is a shaft position sensor.. so it knows when it is slipping...

i guess i will have to dig deeper if it still happening..

i will look around tonight and see if i can find a factory service manual for it..

Thanks again Wayne.

My g/f has pretty much the same truck. She has a p/u though.
3/4 ton.8 bolt wheels.Extended cab.6.0L. Auto..the same transfer case/push button with "Auto 4x4".
Her truck feels "grippy"..in 4x4. In the sense that it does not feel like it is LOCKED in 4x4. Sure..when in tight spaces. Mine felt like it was locked. I THOUGHT that is how they are supposed to feel. No they are not. Hers you can almost feel like there is some slippage. We have the same tires..my Suburban is just waay tooo stoopid heavy..just too much weight on the front wheels.Make no mistake..her truck is a very serious contender for a SERIOUS 4x4! Mine is not. Now that I have driven it a bit since greasing the front shaft..and changing the transfer case fluid it TOO has started to feel "GRIPPY". It feels a lot different that it did!

My buddy has a Yukon XL 4x4..1/2 ton..5.3..much lighter.His truck started to feel "tight" when in 4x4. Not "grippy".We changed the transfer case fluid and it did not make any difference. Then he lost pretty much all power.."service 4x4 light came on". He limped it to the dealer.
Feels looser and "grippy" now.

$1700 later. Encoder motor and front wheel speed sensors.

My Suburban is WAAAY!!! better now Thanks

.I was plowing my lane and really carelessly :oops: :oops: :oops: drove way too close to the side and dropped one of the wheels into the ditch..with the blade on it.
I KNEW there was NO WAY I could get it out...especially after the other day. I didn't even try..just sat there. Gave it a try and it just "gripped" and drove out leaving me speechless. Sure would not have done that last week!!!

Thanks again

Arnold · January 13, 2013, 11:13:45 AM

Quote from: "Arnold"
Quote from: "wayne petty"thats totally bizzare

the rotary encoder counts the steps of the motor position to see how far extended it is... there probably is a shaft position sensor.. so it knows when it is slipping...

i guess i will have to dig deeper if it still happening..

i will look around tonight and see if i can find a factory service manual for it..

Thanks again Wayne.

My g/f has pretty much the same truck. She has a p/u though.
3/4 ton.8 bolt wheels.Extended cab.6.0L. Auto..the same transfer case/push button with "Auto 4x4".
Her truck feels "grippy"..in 4x4. In the sense that it does not feel like it is LOCKED in 4x4. Sure..when in tight spaces. Mine felt like it was locked. I THOUGHT that is how they are supposed to feel. No they are not. Hers you can almost feel like there is some slippage. We have the same tires..my Suburban is just waay tooo stoopid heavy..just too much weight on the front wheels.Make no mistake..her truck is a very serious contender for a SERIOUS 4x4! Mine is not. Now that I have driven it a bit since greasing the front shaft..and changing the transfer case fluid it TOO has started to feel "GRIPPY". It feels a lot different that it did!

My buddy has a Yukon XL 4x4..1/2 ton..5.3..much lighter.His truck started to feel "tight" when in 4x4. Not "grippy".We changed the transfer case fluid and it did not make any difference. Then he lost pretty much all power.."service 4x4 light came on". He limped it to the dealer.
Feels looser and "grippy" now.

$1700 later. Encoder motor and front wheel speed sensors.

My Suburban is WAAAY!!! better now Thanks .I was plowing my lane and really carelessly :oops: :oops: :oops: drove way too close to the side and dropped one of the wheels into the ditch..with the blade on it.
I KNEW there was NO WAY I could get it out...especially after the other day. I didn't even try..just sat there. Gave it a try and it just "gripped" and drove out leaving me speechless. Sure would not have done that last week!!!

Thanks again

I haven't driven it much since I changed the transfer case fluid..I know..I was supposed to.
I thought..and read(man there is a LOT! :!: of wrong information on how these things work :evil: )

I had read that in "Auto" that the transfer case engages the front driveshaft(which is locked/engaged to the front diff) when it there is slippage..difference in rotational speed between the front and rear shaft.
Ahh..no that is not how it works.

SOooo not long after the transfer case fluid was changed..I got stuck in 2wd..shifted into 4wd..and away I went. I thought I should use the other ranges too..get some lube worked in between the clutch plates..shifted to Auto=stuck..2wd=stuck..4 wd Lo=away I went..back to Auto=stuck.
Ok..that part is not working.

I got looking around under there...there is an electric front diff lock too.
Hunh

Had to do some more digging.
In Auto..the front driveshaft is locked with the back driveshaft. Wheel slippage sends info to the front dif lock to lock/unlock as required.
This happens so fast you can't feel it. When you shift into 4wd there is an engagement feel. When you shift into Auto there is no feel.Just that in 2wd if the back wheels are going to spin..then you stop and shift into Auto..there is no spinning of the back wheels seperately.
Something working very well there NOW

Yesterday..I wanted to test it again. I pulled over where there was some loose..gravely stuff. 2wd..a bit of throttle..wheel spin..locker kicks in back end goes squirrely. Fine..into 4wd=all grip. Into Auto=all grip.

Ok that is working.

More digging..I am looking around and come to this big site that
sells transfer cases/parts/modifys them etc.

Hmmm..I had posted at length not long about this.

TIRE SIZE. This site says just to forget about what is on the side of the tires! Get a tape measure and measure the circumference. They say that differences of as little as 1/16" are responsible for almost all transfer case problems with these things! 1/4" can wreck stuff. Wear from non rotated tires can wreck stuff. Even 1/16" can send these things into adaptive mode..so much that they spend so much time in adaptive mode..clutch application/release that it wears the clutches out.

I haven't driven it much since I changed the tires..and the transfer case fluid.

Quite the learning experience this thing :oops:

Arnold · January 13, 2013, 11:22:48 AM

Quote from: "Arnold"
Quote from: "Arnold"
Quote from: "wayne petty"thats totally bizzare

the rotary encoder counts the steps of the motor position to see how far extended it is... there probably is a shaft position sensor.. so it knows when it is slipping...

i guess i will have to dig deeper if it still happening..

i will look around tonight and see if i can find a factory service manual for it..

Thanks again Wayne.

My g/f has pretty much the same truck. She has a p/u though.
3/4 ton.8 bolt wheels.Extended cab.6.0L. Auto..the same transfer case/push button with "Auto 4x4".
Her truck feels "grippy"..in 4x4. In the sense that it does not feel like it is LOCKED in 4x4. Sure..when in tight spaces. Mine felt like it was locked. I THOUGHT that is how they are supposed to feel. No they are not. Hers you can almost feel like there is some slippage. We have the same tires..my Suburban is just waay tooo stoopid heavy..just too much weight on the front wheels.Make no mistake..her truck is a very serious contender for a SERIOUS 4x4! Mine is not. Now that I have driven it a bit since greasing the front shaft..and changing the transfer case fluid it TOO has started to feel "GRIPPY". It feels a lot different that it did!

My buddy has a Yukon XL 4x4..1/2 ton..5.3..much lighter.His truck started to feel "tight" when in 4x4. Not "grippy".We changed the transfer case fluid and it did not make any difference. Then he lost pretty much all power.."service 4x4 light came on". He limped it to the dealer.
Feels looser and "grippy" now.

$1700 later. Encoder motor and front wheel speed sensors.

My Suburban is WAAAY!!! better now Thanks .I was plowing my lane and really carelessly :oops: :oops: :oops: drove way too close to the side and dropped one of the wheels into the ditch..with the blade on it.
I KNEW there was NO WAY I could get it out...especially after the other day. I didn't even try..just sat there. Gave it a try and it just "gripped" and drove out leaving me speechless. Sure would not have done that last week!!!

Thanks again

I haven't driven it much since I changed the transfer case fluid..I know..I was supposed to.
I thought..and read(man there is a LOT! :!: of wrong information on how these things work :evil: )

I had read that in "Auto" that the transfer case engages the front driveshaft(which is locked/engaged to the front diff) when it there is slippage..difference in rotational speed between the front and rear shaft.
Ahh..no that is not how it works.

SOooo not long after the transfer case fluid was changed..I got stuck in 2wd..shifted into 4wd..and away I went. I thought I should use the other ranges too..get some lube worked in between the clutch plates..shifted to Auto=stuck..2wd=stuck..4 wd Lo=away I went..back to Auto=stuck.
Ok..that part is not working.

I got looking around under there...there is an electric front diff lock too.
Hunh Had to do some more digging.
In Auto..the front driveshaft is locked with the back driveshaft. Wheel slippage sends info to the front dif lock to lock/unlock as required.
This happens so fast you can't feel it. When you shift into 4wd there is an engagement feel. When you shift into Auto there is no feel.Just that in 2wd if the back wheels are going to spin..then you stop and shift into Auto..there is no spinning of the back wheels seperately.
Something working very well there NOW

Yesterday..I wanted to test it again. I pulled over where there was some loose..gravely stuff. 2wd..a bit of throttle..wheel spin..locker kicks in back end goes squirrely. Fine..into 4wd=all grip. Into Auto=all grip.

Ok that is working.

More digging..I am looking around and come to this big site that
sells transfer cases/parts/modifys them etc.

Hmmm..I had posted at length not long about this.

TIRE SIZE. This site says just to forget about what is on the side of the tires! Get a tape measure and measure the circumference. They say that differences of as little as 1/16" are responsible for almost all transfer case problems with these things! 1/4" can wreck stuff. Wear from non rotated tires can wreck stuff. Even 1/16" can send these things into adaptive mode..so much that they spend so much time in adaptive mode..clutch application/release that it wears the clutches out.

I haven't driven it much since I changed the tires..and the transfer case fluid.

Quite the learning experience this thing :oops:

Clarifying..differences of as little as 1/16" in tire height. Not circumference.

Rrumbler · January 13, 2013, 02:06:53 PM

:? Ohh, my achin' haid! NP205, Dana 60 front with hubs, Dana 70, Corp. 14 Bolt here I come. :0-0

Arnold · January 13, 2013, 04:08:43 PM

Quote from: "Rrumbler" :? Ohh, my achin' haid! NP205, Dana 60 front with hubs, Dana 70, Corp. 14 Bolt here I come. :0-0

Been there done that. Part time transfer cases(205's as well)(full time transfer cases too).Dana 44-60 F. Up to 70 in the rear. 10/12/14 bolts. 9".All kinds of locking rear axles. Plenty of 4x4's and experiences with them..getting stuck lol.
I gotta admit..this is my very first venture into really,really frikkin' complicated ones!

I am actually stunned :!: at the sheer lack of knowledge..wrong information about them..AND they have been around for 15 years now

I am learning. Have learned.

I HEAR YOU LOUD AND CLEAR MY FRIEND

Would I go back to a non clutch transfer case?

I don't think so. My buddy and g/f are very good drivers,very experienced with 4x4's getting stuck..new ones,old ones. Would they go back? Never.Plus I get to talk to lots of people around here.They wouldn't either.

The application of power WITHOUT wheelspin..via..all kinds of JUNK :evil:

that does break down :evil: :!: all kinds of electronic gizms..clutches..computer stuff. Is something I have seen and felt.

I and others have found that that VERY FIRST bit of wheelspin..the end of continuous forward momentum..and the tearing up and DOWN and INTO "stuck" haha is very critical!These RIDICULOUSLY

complicated systems..can sure make one feel just how good they are when they work right. :!: When they dont..why you just post out here and get your friends (like Wayne) at the RRT to help you out

I mean..IF the RRT ended :cry: THEN back to Dana 60's,NP205's and Dana 70's/14 bolts..but until then I am not going back

I am STILL

trying to get a "feel" for this really aggressive G80 in the back. I AMOST have it figured out. WHEN there is wheelspin..you KNOW it is going to hook up..back off the throttle..just as it hooks up..and you get a bit more bite before you dig yourself in and sink :oops: A conventional locked axle would sink my 'Burb like a stone. Been there done that.

All in fun

Arnold · February 03, 2013, 12:48:50 AM

99 and on GM 4x4 (Auto and electric shift).

Lol I wonder if there is a tsb on this haha..I should look.
Or make one haha.
If only the back wheels are spinning in 4wd.. :evil:
Check of the 3

(2 that have 4x4 stuff in) fuse panels?
Pull the covers..there is a little schematic like thing,really
easy to acess,fuse puller,spare fuses. Nice.

The fuse in the cabin is called "4WD". The one under the hood
is called.."ATC" (Automatic Transfer case).

This was NOT MY truck

And threw NO CEL..no codes :?: No Message centre.
It went into 2wd from 4wd all by it's lonesome

During a nasty winter storm up here..-15-20 C. Snow/whiteouts
road closures/traffic.. since Thursday!.
The little tiny light that tells you what range you are in was out.
Fuse blows..
Why? is next.

wayne petty · February 03, 2013, 01:56:01 AM

automatic transmission diagrams... you did not mention engine or which transmission...

http://www.autozone.com:80/autozone/repairinfo/repairguide/repairGuideContent.jsp?pageId=0996b43f8025ef9f

transfer case wiring diagrams..

http://www.autozone.com:80/autozone/repairinfo/repairguide/repairGuideContent.jsp?pageId=0996b43f8025eeec

you will want to print all the diagrams and figure out which wire goes where...

or narrow down some of the choices ..... there are too MANY variations for me to give you a proper answer

Arnold · February 03, 2013, 01:12:42 PM

Thanks as always Wayne!
I will keep the info you got for me for future reference..in hope I don't need it

Thanks again..
As for this particular vehicle..not mine/not near me. I was there and got this far..(changed the fuse) 4wd is working again..best it go to someone in that area now.