You should not have vacuum to the actuator when in 2HI. The vacuum line should be vented.

Well, how about with it being in 4lo? I have yet to get it back to 2hi. So as soon as I crank up, with it being in 4lo, the vacuum actuator underneath the battery ( when unhooked from the brace that its connected to {with 3 screws}) starts constricting as soon as the engine is started ( while in 4 lo)?

I feel pain, each time I hold down shift and backslash--sorry guys.

Well, considering that vacuum is necessary to pull on the diaphragm to engage the front axle for any 4wd mode, you should have vacuum when in any 4wd mode. So if you are stuck in 4LO and have vacuum to the actuator, the vacuum is at the proper level, and the actuator holds vacuum properly, then it sounds like it is operating as it should.

Just an FYI, but nothing in the front axle will prohibit shifting of the transfer case out of a 4wd mode.

my money is on TCEM.... sounds an awful lot like your encoder has a fail to shift...

$50 to know for sure aint a bad deal... you could always go back and give him $40 cash... cash in hand usually gets the job done... hell tallk to the tech directly and offer him $20 :icon_teeth:

stilllll... it's all for nothing if you dont know what problem you ar ehunting...

ALSO have you searched the forum for other "stuck in 4lo" threads to see what they did? there are a ton. :icon_shrug:

In 2WD the Vacuum switch on teh Transfer case should be Closed ( No vacuum at teh actuator).
If it's in 4Wheel Hi or low then the switch will open to allow Suction to the actuator.
Since you are still in 4Lo, you should have vacuum at the actuator to pull in the Front axle Fork to get the front axles moving with the driveshaft.

Having said that, If there is a leak in the actuator, it will pull in easily with those screws out. In the working position, it has to pull hard against a spring to engage the front Diff. so if it has a leak, it might not have enough suction to pull that cable in hard enough to set off the switch and lock in the front Diff. You should see a tare in the rubber around the actuator if it's bad.

AB,

Man, i have looked all through the site, pretty much what I've been doin while I'm at work...Hope the boss doesn't have a blaze with 4wd problems, haha.

I might break down and get him to check the codes...As for the TCCM, I suppose it could be that. But I dont want to believe it. I took it out, checked all the pins, no water, no nothing. Only a few clicks at crank, 2 maybe?


Now, I spoke with my father today, who was the owner before me. He said that right before I took it over ( 5 years or so ago) he took it to a mechanic to get the codes read. He said he couldnt remember exactly what they said but somewhere along the lines of having to get a part, in the 500$ range that had to be specifically programmed for that particular blazer. That, you couldn't go to a junk yard to get one?? Any ideas about this?

Also, on that note ( which i probalby should have mentioned this days ago, sorry dudes.) I do somewhat recall talking to a college buddy one night ( busch lights involved) well, he taught auto mechanics in highschool and he said something along the lines of " Yeah, I've heard of that. Actually had to replace a few. Messed up installing my first one, I didnt have it set in neutral ( could have been 4hi, 2hi, 4 lo? I cant remember) when you install it..so I had to get a new part and replace it"


This may make no sense...does it ever? haha thanks guys

well hell if you have already plucked the TCEM, why not manualy crank the TC out of 4 lo. there is a shift diagram around here showing where each option (4hi,2hi,n,4lo etc) is in relation to the TC... I beleive it was posted by swartlkk, in response to one of my 4wd questions.... (to help in your search parameters)

the $500 part that has to be programmed and can only be given by God himself on Mt. Blazer is probably the TCCM... they are spendy and hard to come by :icon_shrug:

as for the Busch Light chat (best fishing beer ever, 30pack FTW!) your buddy might have been talking about the TCEM. see, if you screw with it and get it out of sequence, you can ruin it... if you take a TCEM that is sitting in say 4hi, and wedge it into a transfer case that is stuck in 4lo, you will have an unpappy system... :icon_no:
again, this is covered in a post by me about broken 4wd, that a few helpful members took a run at.

Kind of vague, but those would be my guesses.

wow!

first you say,

then you say,

you then finish it off with,

dude, if there is even a pin hole in that diaphram (never mind a tear), it's not gonna pull on the cable properly, so no 4WD.

hmmm........didn't a member post a build on how to overcome this common problem already? :confused:

but the problem here is that he has 4WD. in fact, he's stuck in 4LO. so that post (which the first half parroted Kyle) was kinda off the mark brother. :icon_shrug:

4wd drive battle..for me at least..PT2!!
 

Aight guys, I'm back.


Here's what I've done since last time ( Last time- Stuck in 4low, nothing working to get it out).

I ended up taking the encoder motor off the transfer case so that I can manually shift it to 2HI. Well, I got it off, turned it one click and thats all it would do. Meaning, I couldn't turn the knob that the encoder motor turns ( on the TC) any further without extreme force ( so i stopped). More or less, only could turn it one click.

Went for a test drive, drove ALOT better but when I hit 40 mph, it would start acting funny, this told me that I had switched it from 4LOW to 4HI.
Jacked the front end up, driver side wheel would spin in, what i think is 4hi. But when I switch the transfer case back to where it was in 4lo, the tire would not move.

Now, i'm pretty sure the encoder motor is bad. I havent taken it apart yet, but I do think I see a hint of brown corrosive material where it connects with the Transfer case.

But my question is, if I was to get a new encoder motor...will it go back on properly and allow me to switch to 2hi and all my problems be solved?? Or is the encoder motor even my problem?

I'll give more details if needed.

One thing to remember is that you may have to slightly rotate the input shaft and/or output shaft on the transfer case to do a range shift (from LO range to HI range). I would guess that you ended up with gear to gear interference when you attempted to range shift the transfer case by hand. You may not have gotten it all the way into 4HI.

The new encoder motor will likely be set in 2HI so you will want to make sure that you get the transfer case into position to line up with the new encoder motor.