odd combination of symptoms-Trans/Transfer Case?

sportsfan10

Original poster
Member
May 17, 2017
6
Greenville, SC
Hi all-
I'm a new Trailblazer owner and have searched the forum for an issue exactly like mine. Haven't been able to find it, so I'd like to put it out there for any expert guidance you are willing to offer.
I bought a 2004 Trailblazer LS with about 155,000 miles, routinely maintained by a government agency (not a police vehicle). I knew that it had a transfer case or related issue as it will not move in any gear. Now that I have it in my possession, here are the specifics I know so far-

-Vehicle was taken out of service a year or more ago, so battery had died and vehicle had to be jumped. Had been started and run occasionally over the past year, but not driven.

-Transfer case switch seems to be working fine EXCEPT I can not get it to show neutral. The neutral light does work during the key on / start cycle.

-All other 2wd, 4wd and AWD settings seem to work fine and I can hear the encoder motor working at each setting.

-Vehicle shifts through all transmission shifter settings with no problem. Shifter is not loose as they are when shifter linkage is broken.

-Vehicle engine will rev and TB will roll freely with transmission in Drive. All appearances are that the transfer case is stuck in neutral. This is how I was able to transport it 100 miles from purchase point to home...was able to winch it up onto a car trailer without needing to remove driveshaft.

-In my admittedly limited review of the forum so far, best thinking seems to be that it is the TCCM or a mechanical problem within the transfer case. I have access to 2 good pull-a-parts and am inclined to get a TCCM to try it at this point, but would like to hear thoughts about anything else I should check or how I can pin-point the problem.

-There are no service 4wd or any other lights on. I have a basic scanner and am comfortable digging in to mechanical issues. Less comfortable and knowledgable on electrical stuff although no problem trying with some clear direction.

So, transfer case appears to be stuck in neutral but switch does not/will not show a neutral light. Encoder motor at least makes a noise as though it is working/moving at each setting. Vehicle revs but will not move in any gear.

Sorry for the long first post, but I'm anxious to start enjoying my Trailblazer and hope to get it on the road by this week-end. Thanks for any guidance!
 
Last edited by a moderator:

Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
Have you had a look at the FAQ and this thread?
4WD not working? Step inside.

Just one question. When you put it in Park, does it still roll?
 

sportsfan10

Original poster
Member
May 17, 2017
6
Greenville, SC
Hi all-
I'm a new Trailblazer owner and have searched the forum for an issue exactly like mine. Haven't been able to find it, so I'd like to put it out there for any expert guidance you are willing to offer.
I bought a 2004 Trailblazer LS with about 155,000 miles, routinely maintained by a government agency (not a police vehicle). I knew that it had a transfer case or related issue as it will not move in any gear. Now that I have it in my possession, here are the specifics I know so far-

-Vehicle was taken out of service a year or more ago, so battery had died and vehicle had to be jumped. Had been started and run occasionally over the past year, but not driven.

-Transfer case switch seems to be working fine EXCEPT I can not get it to show neutral. The neutral light does work during the key on / start cycle.

-All other 2wd, 4wd and AWD settings seem to work fine and I can hear the encoder motor working at each setting.

-Vehicle shifts through all transmission shifter settings with no problem. Shifter is not loose as they are when shifter linkage is broken.

-Vehicle engine will rev and TB will roll freely with transmission in Drive. All appearances are that the transfer case is stuck in neutral. This is how I was able to transport it 100 miles from purchase point to home...was able to winch it up onto a car trailer without needing to remove driveshaft.

-In my admittedly limited review of the forum so far, best thinking seems to be that it is the TCCM or a mechanical problem within the transfer case. I have access to 2 good pull-a-parts and am inclined to get a TCCM to try it at this point, but would like to hear thoughts about anything else I should check or how I can pin-point the problem.

-There are no service 4wd or any other lights on. I have a basic scanner and am comfortable digging in to mechanical issues. Less comfortable and knowledgable on electrical stuff although no problem trying with some clear direction.

So, transfer case appears to be stuck in neutral but switch does not/will not show a neutral light. Encoder motor at least makes a noise as though it is working/moving at each setting. Vehicle revs but will not move in any gear.

Sorry for the long first post, but I'm anxious to start enjoying my Trailblazer and hope to get it on the road by this week-end. Thanks for any guidance!
Have you had a look at the FAQ and this thread?
4WD not working? Step inside.

Just one question. When you put it in Park, does it still roll?

Thank your for your prompt response. Just checked and it does not roll in Park but does roll in all other transmission settings including R.
I did see the FAQ and will go through that process this evening. I didn't have a partner yesterday, so I couldn't conclusively determine whether I heard both distinct motor noises. The 4wd switch selector working for everything but N was a symptom I didn't see on any other posting, so I thought it might be significant.
Battery is now dead again, so I'll be replacing the battery tonight as well. Does not rolling in Park lead toward a transmission rather than transfer case issue?
Thanks again for any guidance.
 

Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
If it doesn't roll, I'm afraid it's not the transfer case but the tranny. If it would have been in neutral, it would have rolled so connection from wheels to the tranny is there. If you're getting absolutely nothing, I'm thinking it could be the tranny fluid pump. Is the fluid level good? Smell?
 

sportsfan10

Original poster
Member
May 17, 2017
6
Greenville, SC
If it doesn't roll, I'm afraid it's not the transfer case but the tranny. If it would have been in neutral, it would have rolled so connection from wheels to the tranny is there. If you're getting absolutely nothing, I'm thinking it could be the tranny fluid pump. Is the fluid level good? Smell?
Had some time with the TB last night. Transmission fluid is black and thick, doesn't smell burnt and don't see any specks or shavings in it...but definitely not good. So much for the government agency that said all routine maintenance was done on schedule. I'm thinking this could even be the original tranny fluid. So -- step 1 I'm thinking is to check tranny fluid level without engine running and then check with engine running to see if the level drops any. That should tell me if the pump is totally fried. Is that a reasonable way to determine status of the pump?
If it's not dead, then I'll probably change the fluid but not do a full flush. I'm thinking I'll take a transmission cooler line loose to pump as much out as I can, then drop the pan and do a filter change. My understanding is that will likely change out about 3/4 or so of the fluid. Would you recommend anything else? I have had good experience with Lucas in the past for slipping transmissions and my mechanics were Lucas fans when I managed a shop. Should I add some on refill or just fluid and see if the pump is completely dead or the fluid is just so thick that it won't pump. Thanks!
 

Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
Unhooking a cooler line will definitely tell you if the oil.pump works. If it's that black and soupy, I'd do a flush. Search for @MAY03LT 's video on YouTube on it.
 

Reprise

Lifetime VIP Donor
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Jul 22, 2015
2,724
If the fluid is really that 'thick' - and you think it might really be the factory fill - I'd say there's a better than even chance that your filter might be clogged (meaning nothing gets to the pump...so same result). I'd drop the pan, replace filter & refill w/ cheap fluid *before* doing the manual flush, myself - having new fluid / filter will give the best chance of the pump actually getting a supply of fluid - and being able to pump it, if it's not trashed. The filter / pan clearance isn't that large, either. I'll admit, you write 'thick', and I start thinking 'sludge' - hopefully it's not *that* bad... but trans fluid is usually really 'thin', so...

If the pump turns out to be trashed, I think you'll be replacing more than the pump, to be honest - but the trans has to come out to replace the pump, anyway - so it won't be too much more effort for a teardown, once the pump is out.

Hope you got a good price on the vehicle; if it needs a new trans, that's likely going to run about $800 or so for a used one; a bit more if you purchase a rebuilt one with new parts. Depending on what you paid, you may not want to throw more money into it - ?

On the Lucas additives - from what I see, most here don't put much stock in their products - some do, but I think the consensus pretty much runs 'against'. With what you have now, it might be worth a shot - ?
 

sportsfan10

Original poster
Member
May 17, 2017
6
Greenville, SC
Thanks...yeah got it for $950, so even though their 'mechanics' told me it wasn't a transmission problem but a transfer case problem; there's room even to put a used transmission in it cuz it's nice otherwise. I can get a used transmission with 90 day warranty from my local pull-a-part for $200, $30 of which is a core charge. Part outs from individuals around here seem to be in the $350 - $400 range but of course no warranty. Completely rebuilt $900 exchange, carry out or $1300 installed at a quick glance. So I don't think I'll be in too bad shape even if that's the way I have to go.
But... looking further at it today, the tranny fluid is dark and 'thick' (I know that's a relative term). Not quite sludgy but definitely not thin. Consistency sort of like motor oil that is due for a change. Thing is...as I tried to check the level not running then running, it is so overfilled that it's hard to even read the level. A good 3 inches or so up the dipstick from full. It's as though someone was changing the fluid but forgot to drop the pan, empty it and change the filter. Or maybe it was having problems so they just kept adding fluid thinking that would fix it.
I don't know the impact of being that overfilled on TB transmissions but I know nothing good can come of it. So, I guess first order of business is to drain or pump some fluid out so I don't get totally covered :>}, drop the pan and change the filter, refill to the right level and see what I have...
Thanks for your help. If you have any other thoughts please let me know. I'll be tackling it this weekend and will let you know how it goes.
 

Tiggerr

Member
Jun 6, 2013
1,324
Perrysburg, OH
It's possible some idiot put motor oil in the damn thing... wouldn't be the first time I saw that...

I'd pull the pan/filter as said then try to flush via the lines... see what you get out of them if anything... might not have made it all the the way through the trans...
maybe you get lucky and it's all still mostly in he pan..
Cheap and worth a shot anyway...
 

sportsfan10

Original poster
Member
May 17, 2017
6
Greenville, SC
Thanks Tigerr (by chance an Auburn or Clemson Tiger?), Reprise and Mooseman. Taking care of the overfill, dropping the pan and putting some new fluid in this week-end. Will do a manual flush too depending on what I see and how thick it really is once I can get my hands into it and see how clogged the filter is...
Will let you know next week if I'm lucky and driving or unlucky/in the market for a rebuild or new transmission...
 

Tiggerr

Member
Jun 6, 2013
1,324
Perrysburg, OH
Thanks Tigerr (by chance an Auburn or Clemson Tiger?), Reprise and Mooseman. Taking care of the overfill, dropping the pan and putting some new fluid in this week-end. Will do a manual flush too depending on what I see and how thick it really is once I can get my hands into it and see how clogged the filter is...
Will let you know next week if I'm lucky and driving or unlucky/in the market for a rebuild or new transmission...

Definitely NOT an Auburn or Clemson Tiger....lmao

I bleed scarlet and grey! BUCKEYES ALL THE WAY

:2thumbsup:
 
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Reprise

Lifetime VIP Donor
Supporting Donor
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Jul 22, 2015
2,724
My friend's daughter went to Auburn; she was there when Cam's team won the NCAA championship. So I'll return your 'War Eagle' - much preferred to 'Bama :smile:

Good luck and let us know how it turns out. Although for $200, I might grab one of those pick&pulls, skip the core return, and use your old one to rebuild for later (find a builder if needed) - especially if the rest of the truck is nice. Note that '05 and up has a separate TCM on the trans case; '02 - '05 transmissions are controlled by the PCM.
 
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