the 4x4 vacuum thread. - Page 4 - S-10 Forum
S-10 Forum is the resource on GM S-series trucks, Suspension, engine information, Body Modifications, painting tutorials.  Modifications to suit every need, budget and whim

the 4x4 vacuum thread.

Go Back   S-10 Forum > Suspension Tech > Liftin' It > 4wd IFS
New User? Register Forgot Password


 
LinkBack Thread Tools
Old 12-08-2009, 08:44 PM   #151
carolinatruckscene.com
 
leprechaun1874's Avatar
 
Join Date: Jul 2006
Posts: 3,162
Location: Charlotte
User is: OffLine
Re: the 4x4 vacuum thread.

Yhea, from the front diff. my bad. I don't think its very far. maybe an inch or less. I think you would need to pull the cable and engage the 4wd at the t-case also.
Old 12-09-2009, 12:13 PM   #152
Registered User
 
tonkaman's Avatar
 
Age: 23
Join Date: Mar 2009
Posts: 508
Location: Montana
User is: OffLine
Re: the 4x4 vacuum thread.

hmm ok i think im just gonna replace all the vac lines as they are dry rotted pretty bad, how much does the switch in the t case and the diaphram run usually, and is there anything in the front diff that could be bad and need replacing?
Old 12-09-2009, 01:55 PM   #153
Registered User
 
Age: 25
Join Date: Nov 2009
Posts: 19
Location:
User is: OffLine
Re: the 4x4 vacuum thread.

Is it hard to replace the vaccum actuator on a 96' chevy blazer? I know its under the battery tray, but is there anything that i have to take caution of before replacing it?
Old 12-13-2009, 09:43 PM   #154
Registered User
 
Age: 40
Join Date: Dec 2009
Posts: 1
Location:
User is: OffLine
Re: the 4x4 vacuum thread.

First of all great thread explaining the vacuum system on the S10! I am still a little confused, I've replaced the actuator under the battery tray, replaced the switch on the t-case that has 3 hoses coming out of it, and tried the vice grip trick locking the cable in permanently. Still no 4WD in hi or lo. The front shaft under the drivers seat locks in when 4HI button is pushed and tranny in N, it spins freely when 2HI button is pushed and tranny in N. Does this means it's an electrical issue? I have had some ABS issues recently, think it's a sensor as the ABS goes off when I get below 5MPH, every single time I stop. Not sure if that's related or not. Any help would be much appreciated.
2002 S10, 200k miles, 233 transfer case.

Last edited by cyclonewoody; 12-13-2009 at 09:46 PM.
Old 12-17-2009, 04:52 PM   #155
Registered User
 
Wilson4x4's Avatar
 
Join Date: Dec 2009
Posts: 36
Location: Ottawa, Ontario Canada
User is: OffLine
Re: the 4x4 vacuum thread.

This thread helped me so much today! Thank you. I had no idea why my 4x4 wasn't engaging so a quick read of this thread then I had my truck on the hoist, checked all my lines... Then sure enough I pull out the switch on the tcase and its stuck in. Anyways few bucks and a few minutes later I had 4x4 working like a champ. Thanks!
Old 12-30-2009, 10:41 PM   #156
Registered User
 
94RedSonoma's Avatar
 
Age: 22
Join Date: Aug 2009
Posts: 87
Location: New Hampshire
User is: OffLine
Re: the 4x4 vacuum thread.

I've been messing around with my intake lately and my question is. if that vacuum line that goes to my intake is loose...or not hooked up. will that cause the 4x4 to not engage?
Old 01-01-2010, 02:05 AM   #157
Registered User
 
Wilson4x4's Avatar
 
Join Date: Dec 2009
Posts: 36
Location: Ottawa, Ontario Canada
User is: OffLine
Re: the 4x4 vacuum thread.

that may be...
Old 01-03-2010, 07:23 PM   #158
Registered User
 
tonkaman's Avatar
 
Age: 23
Join Date: Mar 2009
Posts: 508
Location: Montana
User is: OffLine
Re: the 4x4 vacuum thread.

hey so i took a vacuum cleaner to the diaphragm and it pulls the cable but not far enough. the 4x4 still doesnt engage. so i removed the cable from the truck and its not broken but there was about a cup or so of milky oil in the plastic deal that bolts to the front diff. then i pulled the shift fork out by hand and the 4x4 engaged yay! my question is, should there be oil in the plastic deal? and why didnt the diaphragm pull the cable far enough to engage it? is it time for a new diaphragm?
Old 01-05-2010, 04:02 PM   #159
Grounded 4 Life
 
NJ4X4BLAZE's Avatar
 
Age: 35
Join Date: Jun 2005
Posts: 380
Location: North Jersey
User is: OffLine
Re: the 4x4 vacuum thread.

Here are some pics of the vacuum switch location I found online.

Old 01-07-2010, 03:35 PM   #160
▂ ▃ ▅ ▆ █ ▆ ▅ ▃ ▂
 
ZQ8 Blazer's Avatar

 
Age: 31
Join Date: Jul 2004
Posts: 28,155
Location: Western, Ky
User is: OffLine
Re: the 4x4 vacuum thread.

Great thread, wish I had found it earlier. I have a 98 push button and here's my problem, the transfer case is working as it should but whether it's in 2wd or 4wd when I turn the front wheels by hand the front driveshaft turns, I know it isn't suppose to do this. So is it a cable, actuator, or vacuum problem? How do I know which one it is forsure? What do I do to engage and disengage the 4wd?

Last edited by ZQ8 Blazer; 01-07-2010 at 03:40 PM.
Old 01-08-2010, 08:09 AM   #161
Grounded 4 Life
 
NJ4X4BLAZE's Avatar
 
Age: 35
Join Date: Jun 2005
Posts: 380
Location: North Jersey
User is: OffLine
Re: the 4x4 vacuum thread.

look at the acuator and see if its still under vacuum when in 2wd. That's how I knew the vacuum switch was bad. I know my drive shaft used to move as well, but I just replaced my vacuum switch the other day so I need to see if that solved that issue as well.
Old 01-08-2010, 12:52 PM   #162
▂ ▃ ▅ ▆ █ ▆ ▅ ▃ ▂
 
ZQ8 Blazer's Avatar

 
Age: 31
Join Date: Jul 2004
Posts: 28,155
Location: Western, Ky
User is: OffLine
Re: the 4x4 vacuum thread.

Ok I'll do that. Is that the switch at the end of the cable by the differential on ours? So you don't think it would be the actuator itself?
Old 01-08-2010, 12:54 PM   #163
Grounded 4 Life
 
NJ4X4BLAZE's Avatar
 
Age: 35
Join Date: Jun 2005
Posts: 380
Location: North Jersey
User is: OffLine
Re: the 4x4 vacuum thread.

It's #3 in the diagram above. It's located above the transfer case.
Old 01-09-2010, 05:53 PM   #164
▂ ▃ ▅ ▆ █ ▆ ▅ ▃ ▂
 
ZQ8 Blazer's Avatar

 
Age: 31
Join Date: Jul 2004
Posts: 28,155
Location: Western, Ky
User is: OffLine
Re: the 4x4 vacuum thread.

Ok it was always getting a vacuum so i replaced the switch (thanks, NJ4X4BLAZE) and that fixed that problem. But it's still staying in 4wd all the time. The actuator works fine. I took the cable off the actuator and it moves freely like it should. Then put it back on and it put itself into 2wd. When I got in the Blazer and put it in 4wd it worked but when I put it in 2wd it was still in 4wd. What else could it be?
Old 01-09-2010, 10:05 PM   #165
2000 noma highrider
 
Toyota h8r's Avatar
 
Age: 27
Join Date: Mar 2008
Posts: 516
Location: Sylvania, Oh
User is: OffLine
Re: the 4x4 vacuum thread.

i have to convert to a posi-lock due to ALMOST exploded my front diff thanks to my vacuum actuator losing "vacuum signal" at wide open throttle in the snow. The truck shook hard and banged loudly twice before i could get out of the gas.

You might ask why was i at WOT in snow/ice? I was trying to pull a fullsized f350 out of a ditch

i hate my s10 and its cute IFS
Old 01-10-2010, 04:23 PM   #166
▂ ▃ ▅ ▆ █ ▆ ▅ ▃ ▂
 
ZQ8 Blazer's Avatar

 
Age: 31
Join Date: Jul 2004
Posts: 28,155
Location: Western, Ky
User is: OffLine
Re: the 4x4 vacuum thread.

NM. I was reading on here and I have to put it in reverse and then back into drive in it shifts into 2hi
Old 01-11-2010, 07:03 AM   #167
Grounded 4 Life
 
NJ4X4BLAZE's Avatar
 
Age: 35
Join Date: Jun 2005
Posts: 380
Location: North Jersey
User is: OffLine
Re: the 4x4 vacuum thread.

Good to see your problem has been solved.
Old 01-12-2010, 06:09 AM   #168
that guy
 
LBD44's Avatar
 
Age: 25
Join Date: Mar 2009
Posts: 167
Location: La Grange KY
User is: OffLine
Re: the 4x4 vacuum thread.

so im wantin to elimenate vacuum system kinda im gona explain i kno my transfercase is workin and i kno my front axle is lockin in cuz i can pull the cable by hand and lock the front axle but it wont lock in on its own so i was just gona run a vacuum line from the t on the drivers side down to the acuator with a valve on it but where would i cap off my vacuum line runnin to my tranny do i need the line that runs to the tranny?
Old 01-12-2010, 10:24 PM   #169
that guy
 
LBD44's Avatar
 
Age: 25
Join Date: Mar 2009
Posts: 167
Location: La Grange KY
User is: OffLine
Re: the 4x4 vacuum thread.

ok well i rigged up a system for my 4wd acuator i just rerouted the line that goes to the transfercase and ran a brand new vacuum line from that to a switch and then to the acuator i have pics if i can figure out how to post them
Old 01-12-2010, 10:55 PM   #170
that guy
 
LBD44's Avatar
 
Age: 25
Join Date: Mar 2009
Posts: 167
Location: La Grange KY
User is: OffLine
Re: the 4x4 vacuum thread.

ok i think i have the pictures on this msg i outlined the vacuum hose i used and how i ran it and u can see where i put the shut off valve and how its hooked up and it works perfect and only cost me 20 bucks at discount
Attached Thumbnails
the 4x4 vacuum thread.-hpim0988.jpg   the 4x4 vacuum thread.-hpim0989.jpg   the 4x4 vacuum thread.-hpim0993-edited.jpg   the 4x4 vacuum thread.-hpim0992.jpg   the 4x4 vacuum thread.-hpim0991-edited.jpg  


Last edited by LBD44; 01-12-2010 at 10:57 PM. Reason: forgot to add price
Old 02-11-2010, 10:29 AM   #171
Registered User
 
mrriverajr's Avatar
 
Age: 40
Join Date: Aug 2007
Posts: 101
Location:
User is: OffLine
Re: the 4x4 vacuum thread.

This is a great thread, I have to start troubleshooting my lack of 4wd and this thread just might help.
I got stuck in 2ft of snow thanks to the NJ Storm last night and it was quite embarrassing watching people look at me saying man that ZR-2 sucks!!!! LOL
I put the switch to 4wd Hi and I hear a click outside but no front wheel engagement I also tried in 4wd Lo and still no front wheel engagement. The lights do Light up and stay lit saying I am in 4wd mode but Nothin.

Any other tips?????
Old 02-11-2010, 11:01 AM   #172
Registered User
 
94RedSonoma's Avatar
 
Age: 22
Join Date: Aug 2009
Posts: 87
Location: New Hampshire
User is: OffLine
Re: the 4x4 vacuum thread.

hey mrriverajr i had that same problem, still do actually.. for me it was a little plastic clip inside the actuator on the front end. the clip had broke so it wasnt' holding the cable tight to engage into and out of 4 wheel. I'd lift the truck up and put it into 4wheel and see if the front shaft spins, if it does than its your actuator...hope this helped a little.
Old 02-11-2010, 05:20 PM   #173
Registered User
 
mrriverajr's Avatar
 
Age: 40
Join Date: Aug 2007
Posts: 101
Location:
User is: OffLine
Re: the 4x4 vacuum thread.

I am gonna check it out tomorrow. I think I am leaning towards a Posi Lok system.
Old 02-11-2010, 06:58 PM   #174
Registered User
 
94RedSonoma's Avatar
 
Age: 22
Join Date: Aug 2009
Posts: 87
Location: New Hampshire
User is: OffLine
Re: the 4x4 vacuum thread.

yeah i'de like to invest in one of those too, unless i could make one cheaper
Old 02-12-2010, 08:40 AM   #175
Registered User
 
mrriverajr's Avatar
 
Age: 40
Join Date: Aug 2007
Posts: 101
Location:
User is: OffLine
Wink Re: the 4x4 vacuum thread.

Ok so I removed that vacuum actuator today and plugged the vacuum line. I tried pulling the actuator cable leading to the front axle and the wire would not even move. The vacuum actuator seemed to work every time i put the vacuum line to it. I am assuming the actuator cable is frozen not allowing the shift fork to move.
I gotta keep trouble shooting it but its freezing out an i am numb...LOL I will keep you all posted!!!!

[/quote]
Old 02-12-2010, 08:50 AM   #176
I Rather Be Wheelin'
 
ChrisInVT's Avatar
 
Join Date: May 2007
Posts: 4,830
Location: The Woods, VT
User is: OffLine
Re: the 4x4 vacuum thread.

Quote: Originally Posted by mrriverajr
Ok so I removed that vacuum actuator today and plugged the vacuum line. I tried pulling the actuator cable leading to the front axle and the wire would not even move. The vacuum actuator seemed to work every time i put the vacuum line to it. I am assuming the actuator cable is frozen not allowing the shift fork to move.
I gotta keep trouble shooting it but its freezing out an i am numb...LOL I will keep you all posted!!!!
Try having someone drive the truck forward slightly, it seems to tale a little bit of movement to engage sometimes.
Old 02-12-2010, 08:42 PM   #177
Registered User
 
Age: 30
Join Date: Oct 2009
Posts: 5
Location:
User is: OffLine
Re: the 4x4 vacuum thread.

This may be a stupid question, but is there a trick to installing a new vacuum switch into the transfer case? I just bought an '02 ZR2 Ext Cab 4.3L 5spd and the 4x4 didn't work at first, come to find out through research on this site that the plastic part of vacuum switch broke off.... my uncle got the old one out but can't get the new one in. He said something about it being spring loaded.

Any help is appreciated. Thanks!
Old 02-14-2010, 03:23 PM   #178
carolinatruckscene.com
 
leprechaun1874's Avatar
 
Join Date: Jul 2006
Posts: 3,162
Location: Charlotte
User is: OffLine
Re: the 4x4 vacuum thread.

The ball in the bottom is spring loaded. It might be a tight fit to get the switch in.

Last edited by leprechaun1874; 02-14-2010 at 03:24 PM.
Old 03-05-2010, 12:45 PM   #179
Registered User
 
Drjeffro's Avatar
 
Join Date: Mar 2006
Posts: 93
Location: Henderson, NV
User is: OffLine
Re: the 4x4 vacuum thread.

Quote: Originally Posted by boardsilly
this seems like the place to ask this. if i have a vacuum leak on my hvac switch would that vacuum leak in the system cause my 4 wheel to try to engage while i am driving at 70mph? so far it has happened 3 times. i plugged off the vacuum line while i wait for the hvac control panel and haven't had the problem happen since. so what do you guys think?
Mine is doing something similar, and noone can seem to figure it out. I just got the new engine in my truck from the spun crank bearing. But when I run it WOT and let off to slow down, the front axle is trying to engage and makes a horrible clicking sound. If I hit the 4HI button, it stops immeadiately. Under regular acceleration, there is no problem, just when I go WOT, then the noise starts when I slow down.
Old 03-05-2010, 01:22 PM   #180
2000 noma highrider
 
Toyota h8r's Avatar
 
Age: 27
Join Date: Mar 2008
Posts: 516
Location: Sylvania, Oh
User is: OffLine
Re: the 4x4 vacuum thread.

Quote: Originally Posted by mrriverajr
This is a great thread, I have to start troubleshooting my lack of 4wd and this thread just might help.
I got stuck in 2ft of snow thanks to the NJ Storm last night and it was quite embarrassing watching people look at me saying man that ZR-2 sucks!!!! LOL
I put the switch to 4wd Hi and I hear a click outside but no front wheel engagement I also tried in 4wd Lo and still no front wheel engagement. The lights do Light up and stay lit saying I am in 4wd mode but Nothin.

Any other tips?????
welcome to owning a gm failure.......

im switching to the bravada axle and tube to get rid of the vacuum failure system. No more waiting for the axle to engage or disengage ...or not engage at all. No more replacing vacuum lines, actuators and transfercase switches
Old 03-12-2010, 11:22 AM   #181
Registered User
 
Join Date: Mar 2010
Posts: 1
Location:
User is: OffLine
Re: the 4x4 vacuum thread.

Hello,
I realize this is and old thread but I'm hoping somebody is still out there. Am I correct that if I have transmission fluid in my vacuum lines and actuator that my switch is bad at the transfer case?
Old 03-22-2010, 09:59 AM   #182
Registered User
 
relic's Avatar
 
Join Date: Mar 2010
Posts: 3
Location: Nova Scotia
User is: OffLine
Re: the 4x4 vacuum thread.

G'day.
Just joined,just got my first S10 with the push button 4x,I've had four other S10 4x's but they were manual shift.
My front axel won't engage and have narrowed it down to the vacume switch,the switch on mine looks like it's on top of the TC,not screwed into the side. Am I looking at the right thing?
Old 03-22-2010, 12:49 PM   #183
Registered User
 
Drjeffro's Avatar
 
Join Date: Mar 2006
Posts: 93
Location: Henderson, NV
User is: OffLine
Re: the 4x4 vacuum thread.

Mine is fixed now. It was a vacuum leak, I still don't understand why a vacuum leak would have the front diff partially engaging.
Old 03-22-2010, 12:50 PM   #184
Registered User
 
Drjeffro's Avatar
 
Join Date: Mar 2006
Posts: 93
Location: Henderson, NV
User is: OffLine
Re: the 4x4 vacuum thread.

Quote: Originally Posted by relic
G'day.
Just joined,just got my first S10 with the push button 4x,I've had four other S10 4x's but they were manual shift.
My front axel won't engage and have narrowed it down to the vacume switch,the switch on mine looks like it's on top of the TC,not screwed into the side. Am I looking at the right thing?
The part on the side of the TC is a switch, when the TC is shifted, it transfers vacuum to the diaphram that is usually mounted up near the battery, the diaphram then pulls a cable that engages the front diff.
Old 03-22-2010, 10:03 PM   #185
69xx69
 
Age: 22
Join Date: Mar 2010
Posts: 15
Location: sedro-woolley wa.
User is: OffLine
Re: the 4x4 vacuum thread.

hey, so if i were to put a cherokee dana 30 under my truck would the vacum lines work for that axle?? would they just hook right up do you know??
thanx
Old 03-25-2010, 11:08 AM   #186
carolinatruckscene.com
 
leprechaun1874's Avatar
 
Join Date: Jul 2006
Posts: 3,162
Location: Charlotte
User is: OffLine
Re: the 4x4 vacuum thread.

relic~ the vacum switch is on top of the TC. It has 3 lines going to it if the lines are gone you should be able to feel the 3 prongs. The switch looks like this




burnett ~ If you do a SFA you don't need the vacum system
Old 03-25-2010, 01:05 PM   #187
2000 noma highrider
 
Toyota h8r's Avatar
 
Age: 27
Join Date: Mar 2008
Posts: 516
Location: Sylvania, Oh
User is: OffLine
Re: the 4x4 vacuum thread.

Quote: Originally Posted by leprechaun1874
relic~ the vacum switch is on top of the TC. It has 3 lines going to it if the lines are gone you should be able to feel the 3 prongs. The switch looks like this



burnett ~ If you do a SFA you don't need the vacum system
IIRC 87-95 dana30 from yj/xj had a vacuum locking right axle.....fails


http://cgi.ebay.com/ebaymotors/ws/eB...d=290325372631


lolololololol

could make it work like a stock s10 if done right i bet
Old 03-25-2010, 02:35 PM   #188
carolinatruckscene.com
 
leprechaun1874's Avatar
 
Join Date: Jul 2006
Posts: 3,162
Location: Charlotte
User is: OffLine
Re: the 4x4 vacuum thread.

Quote: Originally Posted by Toyota h8r
IIRC 87-95 dana30 from yj/xj had a vacuum locking right axle.....fails

could make it work like a stock s10 if done right i bet
Well then don't use that axle.
Old 03-28-2010, 11:05 PM   #189
69xx69
 
Age: 22
Join Date: Mar 2010
Posts: 15
Location: sedro-woolley wa.
User is: OffLine
Re: the 4x4 vacuum thread.

alrite hey thanx guys...but i decided not to use that axle anymore lol im using 1/2 ton running gear and droping a 350 in my truck or a 454 i can make it work and i have the 454 just has a loud knock in it but its getting a rebuild.... lol im gunna try for the 454 though
Old 05-26-2010, 07:46 AM   #190
Registered User
 
Join Date: May 2010
Posts: 8
Location:
User is: OffLine
Re: the 4x4 vacuum thread.

OK, I see this a old thread. but does anybody know where one can get that rubber plug. I need to run new vacuum lines, my vacuum one is plugged and I cant get the plug off the hose.. my switch is fine.
Old 06-28-2010, 08:18 PM   #191
Registered User
 
Age: 23
Join Date: Jun 2010
Posts: 1
Location:
User is: OffLine
Re: the 4x4 vacuum thread.

i tried putting my 84 s15 into 4x4 and ran into the same problem. afte putting in back into the 2 wheel drive it wouldnt move. is it possible that without the vac lines it would get locked in neutral? i found where the lines r suppost to go, along with the vac lines missing the other end of the 3 prong connecter is also gone.

also the previous owner connected the actuator vac line to the back of the manifold. when i removed it , my truck ran horrible and was misfiring.

i connected vac lines into the correct holes, without the connecter but it wouldnt work.
Old 06-29-2010, 01:19 AM   #192
Registered User
 
Join Date: May 2010
Posts: 8
Location:
User is: OffLine
Re: the 4x4 vacuum thread.

the vac lines are just for the front axle to engage and disengage, now if you put in 4x4 and back into 2x4 and it don't move it is either your linkage or transfer case is shot?

if yours dont work with vac lines connected direct to carb to actuator, then your actuator or cable is shot?
Old 07-02-2010, 07:38 AM   #193
carolinatruckscene.com
 
leprechaun1874's Avatar
 
Join Date: Jul 2006
Posts: 3,162
Location: Charlotte
User is: OffLine
Re: the 4x4 vacuum thread.

Quote: Originally Posted by skybolt58
OK, I see this a old thread. but does anybody know where one can get that rubber plug. I need to run new vacuum lines, my vacuum one is plugged and I cant get the plug off the hose.. my switch is fine.
What 'rubber plug' are you talking about? If you are talking about one on the end of a vacume line try autoparts store. any kind of plug should work.
Old 07-02-2010, 07:46 AM   #194
carolinatruckscene.com
 
leprechaun1874's Avatar
 
Join Date: Jul 2006
Posts: 3,162
Location: Charlotte
User is: OffLine
Re: the 4x4 vacuum thread.

Quote: Originally Posted by psiscorpian
i tried putting my 84 s15 into 4x4 and ran into the same problem. afte putting in back into the 2 wheel drive it wouldnt move. is it possible that without the vac lines it would get locked in neutral? i found where the lines r suppost to go, along with the vac lines missing the other end of the 3 prong connecter is also gone.

also the previous owner connected the actuator vac line to the back of the manifold. when i removed it , my truck ran horrible and was misfiring.

i connected vac lines into the correct holes, without the connecter but it wouldnt work.
even if your vacum lines are not hooked up the tranfer case will still shift. you can feel the difference in 'power' it just wont send power to the front axle. when you put it back in 2wd it should go back to normal.
Old 08-15-2010, 02:27 PM   #195
Registered User
 
Join Date: Aug 2006
Posts: 115
Location: Biarritz, France
User is: OffLine
Re: the 4x4 vacuum thread.

I just changed all the vac lines on my 98 Blazer but it looks that front axle is not engaging. Should I check first the switch or the Actuator?
Old 08-15-2010, 09:26 PM   #196
Registered User
 
jman85's Avatar
 
Age: 21
Join Date: May 2010
Posts: 2,444
Location: bc canada
User is: OffLine
Re: the 4x4 vacuum thread.

Quote: Originally Posted by Donahue
a lot of people have problems with their 4x4 not working, for various reasons. one of the common reasons is the vacuum actuator going bad, or the vacuum lines going to it. i have gotten a PM from somebody, and i figured i could share some of the info with everyone.

in s10's, when you put it in 4wd (4hi or 4low) with either the 233 (push button) or 231 (manual shift(also 207)), the transfer case has a switch of sorts that tells the front axle to engage. this switch routes vacuum to one of two places. if you are in 4wd (hi or low), the vacuum goes to the actuator. if you are in 2hi then the vacuum gets routed to an orb where it is just stored. this line also supplies the vacuum.

now, the switch it self is on the drivers side, almost at the front of the t-case. it has three vacuum lines going to it. the switch works similar to a ball point pen, meaning there is a round ball that is either pushed or not. the ball gets pushed by the shift fork inside the t-case, when the case is shifted into 4wd. now, there are three vacuum lines going to the switch. one line supplies the vacuum, and stores it in the orb when not in 4wd. one line vents to the open air, and the t-case vent piggy backs onto it. the other line goes to the actuator. all three lines run together up to the passenger side of the bell housing. then two go one way, and one goes the other. the vacuum supply/orb is the line that breaks from the pack and follows over to the drivers side. the other two lines, the vent and the actuator line, continue to run along the passenger side frame rail where they end near the vacuum actuator. one line plugs into the actuator and the other is just a vent that clips onto the inside of the outer fender well.

the actuator takes the vacuum, when supplied, and has a diaphragm that pulls on a cable. this cable runs down to the passenger side of the front differential, and moves a collar back and forth. this collar either connects the passenger side cv shaft to the carrier, or it disconnects it. this is how the 4wd system works on an s10, and all IFS 4x4 gm products (with a few variants).

now the pictures:

this is the switch installed on a 231. note the vent line coming off the t-case


here is where the t-case vent line meets up with the open air circuit.


you can see the lines running along the trans and bell housing


this line goes off to the orb, and supplies the vacuum from the engine


this line will follow the wiring harness and go the orb, located behind the drivers side headlight


this is the orb, aka the vacuum canister


this is where the switch gets vacuum, off the intake


this is the other two lines that go off to the passenger side


they end behind the passenger side headlight


this is the line going into the actuator


the actuator is under the battery tray




now onto the switch. the switch looks like this


if you look at the top, where the lines go in you will notice a little "key"


this lines up with a similar spot on the female end


the three vacuum lines must be in the right spot in order to function properly. take the female end of the vacuum lines, looking at the open end towards you like in the above pic. if you orientate it to where the key is on top, the lines are as followed.
if anyone has any questions, or wants any more pics, just ask.
glad i got a body lift in mine
Old 08-22-2010, 12:58 PM   #197
Registered User
 
Join Date: Aug 2006
Posts: 115
Location: Biarritz, France
User is: OffLine
Re: the 4x4 vacuum thread.

Quote: Originally Posted by tahi
I just changed all the vac lines on my 98 Blazer but it looks that front axle is not engaging. Should I check first the switch or the Actuator?
In fact I double checked and the front axle is engaging. The only probleme is that disengagment is pretty slow is that normal? It takes cometime100 feet driving to quit.

I got a question also : what is the third vac line at the transfer case switch for?
I assume that the first one goes to the vacuum source, the second to the actuator…but what is the third for? On mine it goes to a t junction and one of the branc is going to a final plug under the hood.
Old 08-22-2010, 08:13 PM   #198
carolinatruckscene.com
 
leprechaun1874's Avatar
 
Join Date: Jul 2006
Posts: 3,162
Location: Charlotte
User is: OffLine
Re: the 4x4 vacuum thread.

one line should be vacum source, one is open air vent, the other is the vacum ball. From my understanding.
Old 08-23-2010, 02:00 PM   #199
Registered User
 
Join Date: Aug 2006
Posts: 115
Location: Biarritz, France
User is: OffLine
Re: the 4x4 vacuum thread.

what does the open air vent do? I don't understand the function of this line? Why do teh TC need this vent? Does the switch connect vacuum source to open airvent?
Old 08-24-2010, 09:09 PM   #200
carolinatruckscene.com
 
leprechaun1874's Avatar
 
Join Date: Jul 2006
Posts: 3,162
Location: Charlotte
User is: OffLine
Re: the 4x4 vacuum thread.

To quote jman85~ now, the switch it self is on the drivers side, almost at the front of the t-case. it has three vacuum lines going to it. the switch works similar to a ball point pen, meaning there is a round ball that is either pushed or not. the ball gets pushed by the shift fork inside the t-case, when the case is shifted into 4wd. now, there are three vacuum lines going to the switch. one line supplies the vacuum, and stores it in the orb when not in 4wd. one line vents to the open air, and the t-case vent piggy backs onto it. the other line goes to the actuator. all three lines run together up to the passenger side of the bell housing. then two go one way, and one goes the other. the vacuum supply/orb is the line that breaks from the pack and follows over to the drivers side. the other two lines, the vent and the actuator line, continue to run along the passenger side frame rail where they end near the vacuum actuator. one line plugs into the actuator and the other is just a vent that clips onto the inside of the outer fender well.
Sponsored Links
Advertisement
 

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the S-10 Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT -4. The time now is 07:26 PM.

Powered by vBulletin® Copyright ©2000 - 2011, Jelsoft Enterprises Ltd. SEO by vBSEO 3.2.0
SEO by vBSEO
vBulletin Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.