98 Tahoe 4x4 problem

Hi new to group, I have a 98 Tahoe that up until two days ago ran great! It has lots of Km's on it (250,000). This is the prob, I was running in Auto 4x4 (snow up here in Canada) everything just fine, went to back out of drive
way and notice rear wheel spin, looked down and panel showed 2Hi and red neutral light??? Shut off truck and turned key back on, both 2Hi, red neutral and 4Lo lights come on. When I put it in drive 4Lo light goes off 2Hi stays on and so does red neutral. Truck is only in 2Hi, after a few minutes on the road all lights go out except red neutral, still only in 2Hi. No unusual noise or problems with truck otherwise.
Can this problem be diagnosed with a OBDII reader??
Does this sound like a transfercase solinoid problem or internals?
I have an appointment with the dealership on Wednesday.
Pete
Oh btw, how can I get a shop manual (not Haynes - Useless) dealer says not available.
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. . ====== ====== (slightly edited, partially rearranged) On Sun, Dec 12, 2004, snipped-for-privacy@shaw.ca (TheBuchholds) came running in the room screaming.......
I have a 98 Tahoe that up until two days ago ran great! It has lots of Km's on it (250,000).
==SYMPTOM== I was running in Auto 4x4 (snow up here in Canada) everything just fine, went to back out of drive way and notice rear wheel spin, looked down and panel showed 2Hi and red neutral light???
Truck is only in 2Hi, after a few minutes on the road all lights go out except red neutral, still only in 2Hi.
No unusual noise or problems with truck otherwise.
==DIAGNOSTIC STEPS TAKEN== Shut off truck and turned key back on, both 2Hi, red neutral and 4Lo lights come on. When I put it in drive 4Lo light goes off 2Hi stays on and so does red neutral.
==QUESTIONS== (1) Can this problem be diagnosed with a OBDII reader??
(2) Does this sound like
[a] a transfercase solinoid problem
or
[b] internals?
==foot notes== I have an appointment with the dealership on Wednesday.
Oh btw, how can I get a shop manual (not Haynes - Useless) dealer says not available
Pete =============== ===============. Pete, answers to yer quiz.......
(1) yes
(2) [a] does not exist [b] maybe
There is no such animal as a transfer case solenoid. There IS a motor. It works just like a window motor....sorta,kinda, well.... almost.
There is also an "encoder" that the motor is mounted to. It senses what mode the transferr case is in, and relays that info to the computer.
The Motor is mounted on the Encoder, and the set is then mounted on the transferr case. The switches you push on the dash tell the MOTOR what to do, the ENCODER tells the computer what mode the transferr case is in...or should be in. (gets a little hairy now)
The Encoder-Motor is ONE link in a system that entails an array of wiring and various inputs and outputs that include, but are not limited to, the PCM, VSS, Encoder-Motor, Differential interlock, PRNDL switch, 4wd dash mounted switches, and several, several other various components, any of which WILL cause the lights on switches to act funky, and will limit the mode to 2wd and sometimes 4hi. note....i said wiill....not may...not could.
In order to help you fix it, or to eliminate as much guess work as possible, the first thing that has to be done is to see if any codes MAY be in the computer.
note...i said may...not will....not could..not are.
also note...i said fix..not bypass..not temporarily gain opereation of.
You could jest TRY taking the 4wd fuse out fer least 3 minutes, or unhook the battery, to clear any codes that might be there....and see if the problem goes away. BUT.....it's always best to document ANY codes in the system before clearing the memory, jest for reference for later ..... in case the problem comes back. You could erase a code that's random, and one that doesn't come back when the symptom shows back up. it happens.
There are only 4 codes that it could set, and the actual code will not be giving a definitive failed component, but could narrow down the diagnostic path greatly.
note...i said could...not would.........
maybe i shudda said......should.....
naw....definately.....could.
any whoooo....
you could jest change the switches
you could jest change the motor
you could jest change the encoder
you could jest change the diff interlock
you could jest put in a complete reman transfer case
you could pull codes without an OBD 2 scanner by grounding the wire on the diagnostic connector....
then......... you could do a repost and get some more info.
~:~ MarshMonster ~:~
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Thanks MM
Replacing the 20 amp fuse fixed the problem, I was surprised that the blown fuse was not caught by the ECM as no codes were spit out with the OBD II reader.
Learning every day
pete
(The Buchholds) came running in the room screaming.......
I have a 98 Tahoe that up until two days ago ran great! It has lots of Km's on it (250,000).
==SYMPTOM=I was running in Auto 4x4 (snow up here in Canada) everything just fine, went to back out of drive way and notice rear wheel spin, looked down and panel showed 2Hi and red neutral light???
Truck is only in 2Hi, after a few minutes on the road all lights go out except red neutral, still only in 2Hi.
No unusual noise or problems with truck otherwise.
==DIAGNOSTIC STEPS TAKEN=Shut off truck and turned key back on, both 2Hi, red neutral and 4Lo lights come on. When I put it in drive 4Lo light goes off 2Hi stays on and so does red neutral.
==QUESTIONS=(1) Can this problem be diagnosed with a OBDII reader??
(2) Does this sound like
[a] a transfercase solinoid problem
or
[b] internals?
==foot notes=I have an appointment with the dealership on Wednesday.
Oh btw, how can I get a shop manual (not Haynes - Useless) dealer says not available
Pete =============================. Pete, answers to yer quiz.......
(1) yes
(2) [a] does not exist [b] maybe
There is no such animal as a transfer case solenoid. There IS a motor. It works just like a window motor....sorta,kinda, well.... almost.
There is also an "encoder" that the motor is mounted to. It senses what mode the transferr case is in, and relays that info to the computer.
The Motor is mounted on the Encoder, and the set is then mounted on the transferr case. The switches you push on the dash tell the MOTOR what to do, the ENCODER tells the computer what mode the transferr case is in...or should be in. (gets a little hairy now)
The Encoder-Motor is ONE link in a system that entails an array of wiring and various inputs and outputs that include, but are not limited to, the PCM, VSS, Encoder-Motor, Differential interlock, PRNDL switch, 4wd dash mounted switches, and several, several other various components, any of which WILL cause the lights on switches to act funky, and will limit the mode to 2wd and sometimes 4hi.
note....i said wiill....not may...not could.
In order to help you fix it, or to eliminate as much guess work as possible, the first thing that has to be done is to see if any codes MAY be in the computer.
note...i said may...not will....not could..not are.
also note...i said fix..not bypass..not temporarily gain opereation of.
You could jest TRY taking the 4wd fuse out fer least 3 minutes, or unhook the battery, to clear any codes that might be there....and see if the problem goes away. BUT.....it's always best to document ANY codes in the system before clearing the memory, jest for reference for later ..... in case the problem comes back. You could erase a code that's random, and one that doesn't come back when the symptom shows back up. it happens.
There are only 4 codes that it could set, and the actual code will not be giving a definitive failed component, but could narrow down the diagnostic path greatly.
note...i said could...not would.........
maybe i shudda said......should.....
naw....definately.....could.
any whoooo....
you could jest change the switches
you could jest change the motor
you could jest change the encoder
you could jest change the diff interlock
you could jest put in a complete reman transfer case
you could pull codes without an OBD 2 scanner by grounding the wire on the diagnostic connector....
then......... you could do a repost and get some more info.
~:~ MarshMonster ~:~
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you could pull codes without an OBD 2 scanner by grounding the wire on the diagnostic connector....
~:~ MarshMonster ~:~
Really?
GMC Gremlin
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. . ===== ===== (Concerning getting t-case module codes)
.. you could pull codes without an OBD 2 scanner by grounding the wire on the diagnostic connector.... ~:~ MarshMonster ~:~ ===== ===== On Dec 16, 2004, 1:46am (CST+6) snipped-for-privacy@psudo.com (GMCGremlin) asked:
Really?
GMC Gremlin ======= =======
KJ, yes, really.
~:~ marsh
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Marsh Monster wrote:

Depends on which t/case you are talking about on the 98 Tahoe. If you have the 233, you can pull codes manually, but you can't scan it. If you have the 246 auto, you can't pull codes manually, you have to scan it. You can do one or the other, but you can't do both on either t/case.
Ian
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