Hi I am new here and am looking forward to finding info to repair my trailblazer. I have a 2005 with the GM226HD transfer case in it. I took it in to a local dealer to have the speedomoter repaired and also the 4 wheel drive look at. they fixed the speedo with a new cluster and is working fine now. they also looked at the 4 wheel drive and told me there was nothing wrong, I told them to get it out in the snow with it in 4 whell drive and only one tire will spin. I have had it on the hoist in my garage and can hear both the front diff and the transfer case shifting. I removed a little lube out of the transfer case and see no metal or anything. the dealer said they would have to pull the transfer case and take it apart to find what was wrong. they did say that there was some trouble codes in it but that they were wheel sensors. thanks for the help and look forward to figureing this out. I am able to do most of my own work and take care of 20 or so chevy work vans. thanks again. Mike
02-27-2009, 11:35 AM
i have a 04 and my clutch went on the trans fer case but the front tires would not spin at all and also it would jerk when it should engage cause it was just slipping.
02-27-2009, 12:06 PM
thanks but this thing does not jerk or anything, When i get out on the road with it and it is snow i f i give it much gas the rear wheel spins and there is no shrudders or anything. the light for the 4 wheel is on like it should be. thanks again, Mike
02-27-2009, 02:36 PM
Look in the glovebox for the G80 option. Automatic rear diff locker. It would activate if one rear tire was spinning and not the other.
But on snow, this vehicle really is a one wheel drive if you break it loose and don't have the G80. All the torque leaks out the spinning tire and you have nothing. Only trick to move forward at all is to drag the brakes slightly with your left foot. That absorbs some torque from the spinning tire and gives the other three some.
Unless you did something like put it in 4HI and break all four tires loose as a test.
If you have something broken mechanically in the front axle disconnect, you would hear the actuator but it wouldn't lock the sides together.
I would put the rear up in the air with jack stands, put it in 4LO, lock the rear wheels with the emergency brake, and see if I could drive off the jack stands uaing the front wheels only. I assume you don't have any indicators of electrical trouble like the 4WD selector switch lights flashing or the Service 4WD light on?
02-27-2009, 03:01 PM
Thanks Roadie, I had it up on the lift and found that both front and rear differentals are open. i rotated one wheel and the other side went the other way telling me they are open. I did put it in 4 hi and if i grab the front drivshaft with the trans in park it feels like it is locked in. but I drove it to work from lunch and going down the road 55 mph with it in 4hi on slippery roads i can touch the gas and one back tire will spin. I have read your post on the sounds that you should hear, and mine sounds like everything is shifting fine. its nice to chat on here and get some additional ideas. thanks for all the help.
02-27-2009, 03:36 PM
I'd get somebody outside the car looking as you launch from a stop in 4HI on a slippery surface. The dealer may be right, and all you are seeing is the traditional one spinning wheel issue. Try a hill climb in mud or gravel.
02-27-2009, 05:38 PM
Thanks Roadie, I had it up on the lift and found that both front and rear differentals are open. i rotated one wheel and the other side went the other way telling me they are open. I did put it in 4 hi and if i grab the front drivshaft with the trans in park it feels like it is locked in.
Ok, I think you in the right area, and I think Roadie is pointing you to the problem area.
Just to rehash somewhat.
Yep, both front and rear are open; even if you have the G80 diff, it will appear open until there is some spin detected where upon the internal pawls will active a lock up. The way your testing, the diffs will act as though they are "open". Ok, good test.
Roadie is talking about a disconnect that is built into the front passenger axle. In 2 wd, the disconnect will let this wheel spin free of the diff. Get it up on the lift again. As you said, (in park and 4 hi) the front drive shaft should not turn, and like any open diff, one one wheel is connected to the driveshaft at any given time. But, it can be either wheel on an axle. Try your test again, and turn each front wheel, have a buddy hold the other wheel and you should have resistance with both wheels. If there is no resistance, the front disconnect is not operating.
03-01-2009, 10:15 PM
well guys first of all I would like to thank you for all of your help here. I did the test with one buddy holding one front wheel and it in 4 wheel drive hi and found that the front diff was locking in as the front drive shaft did turn and that something in the transfer case was slipping. I removed the transfercase and found that a piece that is behind the clutch pack in there is busted , it looks like maybe a flat roller brg that came apart. also a rather large spring inside the clutch pack also looks broke. now I am in need of a parts break down and some parts. does anyone have any recomendations of where to find a parts break down and the parts? it was not to bad to get appart and the chain etc looks to be fine. thanks in advance for your help. Mike
03-01-2009, 11:00 PM
Sorry about the problem. Please fix your profile, since you aren't the AWD version if you have the NVG226 TC.
Anyway, here are some pictures and part numbers. You can get them from compnine.com, who provided this nice part catalog, or the discount dealer parts4chevys.com. Or maybe cheaper, an entire Ebay junkyard unit.
. I removed the transfercase and found that a piece that is behind the clutch pack in there is busted , it looks like maybe a flat roller brg that came apart. That is becoming a common problem, a number of people have reported it.
One or 2 ex-gm employees talked about and reported that the newer tx cases have a beefier bearing assembly. Good luck.
03-03-2009, 08:38 AM
Hello all, again I want to thank each and everyone that has hellped me with this. Last night I was able to get the parts i needed and put my transfer case back together and installed in the trailblazer. everything is working fine at this point but have only taken it down the road and back. so time will tell. thanks again to everyone. and will stay in touch on this site, it was a big help. also will look forward to helping others along the way if I can. Mike
03-03-2009, 04:17 PM
Took out the TC, found the problem, BOUGHT THE PARTS, and put it all back together in a day?
You're a better wrench than I, Charlie Brown. :hail:
03-03-2009, 11:39 PM
I should have read more. Mikes problem is identical to mine. I will pull the transfer case and see whaT I find. I will let you know.
03-03-2009, 11:54 PM
Do you have to remove the transfer case from the transmission to take it apart or can you just remove the back half in the car to make the repairs??
03-04-2009, 08:26 AM
Joe, i recomend pulling the transfer case as there is only 5 nuts, driveshafts and the electrical conectors. thats the easy part of the job. there is a gear on the back of it that has to be pulled off. this gear is what the rear sensor reads. i used a puller on it to get it off and watching where it goes on shaft. when i installed it i heated it up a little bit to expand it and slid it on to its location and held it there till it cooled alittle. hope this helps. Mike
11-07-2009, 09:13 PM
I dismantled the transfer case and could not find anything worn or broken. I also replaced the shift motor before I took it out. I just tried running the shift motor (old and new one) off of the transfer case it moved but not in the same location anytime.
Do I need to replace the shift control module?
11-29-2009, 03:57 AM
i have a similar problem with my 2004 trailblazer. when i switch from 2wd to a4wd or 4hi i can hear the transfer case encoder buzzing and i can hear the front hubs whining but it doesnt seem to engage. in my glove box i do have the g80 code and when im on a snowy and icy road in a4wd or 4hi i can take off spinning only the back tires. i looked at the drivers side front tire while my gf watched the passenger front tire and neither one would spin. the lights on my dash switch work fine and only blink for a couple of seconds while its "engaging" and then stay lit up. the check 4x4 light does not come on and i have removed the #8 fuse under hood and a fuse under back seat(cant remember #) for 60 seconds with no luck. can anyone make sense of this?
11-29-2009, 12:42 PM
You probably have the problem of the front axle splined disconnect failing mechanically. There's a rash of these lately as the vehicles age and the GM incompetent design is revealed. Dorman is considering offering replacement parts, but so far nothing is on the market. Search for "splined disconnect" and read some of the other threads. It's basically assembly #56 in this exploded view - mounted on the passenger side of the oil pan where the CV shaft goes.
11-29-2009, 01:06 PM
thanks roadie you really seem to know your 4x4 systems. i hope theres some way i can fix this myself and avoid the stealership. ill check the posts you recomended. ill be fixing this along with changing the transfer case and front and rear diff fluid along with a tranny service. not sure if i should just change fluid in the pan and filter or go for the full flush. i just bought the trailblazer a couple of months ago and want to make sure everything is in tip top shape. thanks again for your help.
11-29-2009, 04:31 PM
Just had a similar problem with my Envoy. it turned out to be the intermediate shaft assembly, which is the mechanical part of the front axle actuator.
One way to find out is to remove the actuator and use a screwdriver or 3/8 socket extension to manually engage the axle with all 4 wheels jacked up and the transfer case in 4 wheel drive position, engine running and in gear. If you cannot engage the front end this way, then the problem is mechanical. Be sure to check that the driveshaft is turning. If it isn't then you're back to transfer case issues.
I replaced the outboard bearings, seal, thrust washers and shifting fork and mine works fine again. It isn't too hard to do, just undoing the upper ball joint and tie rod end will give you enough rooom to clear the assembly with the axle. 4 bolts hold the assembly to the differential.
11-29-2009, 04:54 PM
where did you get your parts from? are they new, aftermarket or used? ill have to wait untill i can pull my trailblazer into the shop to check it out. we have about 6 inches of snow in the driveway so this will be an indoor job.
11-30-2009, 01:03 PM
Got the parts from GM.Depending on what you need, they aren( too pricy. I spent about $150 on mine. Once you take it out and have a look you'll know what you'll need better Hope this helps you.where did you get your parts from? are they new, aftermarket or used? ill have to wait untill i can pull my trailblazer into the shop to check it out. we have about 6 inches of snow in the driveway so this will be an indoor job.
12-01-2009, 12:24 AM
ok so last night i had the gf put the trailblazer in D with it engaged in 4hi while i was underneath pushing in the actuator hole in the splined disconnect with a 3/8 extension and i could feel slight pressure pulsing back but neither one of the front wheels moved anf they still free spin. hopefully tomorrow ill have time to remove the splined disconnect for further inspection. with the upper ball joint and tie rod disconnected will the axle be able to pull out far enough or will the axle have to be removed as well? the less work the better as im working in the driveway in a half a foot of snow. thanks for all the input.