the 4x4 vacuum thread.

[Donahue]

i dont even like the cable system. it seems like a band aid for a poorly designed system. for me it would probably be hubs or just live with the front end always locked up.

[Outlawz24]

Well given my truck is my DD chances are i would just go hubs then. Can always take my time at it and rebuild the axles i use for my swap before i bolt them under the truck. Might as well throw in a warn hub kit at the same time then.

[Fishnic]

What is the cause that makes these t-case actuator switches go out? I got the dreaded hissing vacuum leak behind my hvac control panel and read up about the trans oil being spred thru the system due to faulty tcase actuator switch. i replaced it about 5 weeks ago, and temporarily didnt do anything to the hvac. Now i hear from under the truck, the same chirping noise that the actuator switch made when it was bad. the switch went out again?

[Donahue]

Quote: Originally Posted by Fishnic

What is the cause that makes these t-case actuator switches go out? I got the dreaded hissing vacuum leak behind my hvac control panel and read up about the trans oil being spred thru the system due to faulty tcase actuator switch. i replaced it about 5 weeks ago, and temporarily didnt do anything to the hvac. Now i hear from under the truck, the same chirping noise that the actuator switch made when it was bad. the switch went out again?

age usually. the actuator should work as long as the diaphragm is intact.

[bubbagt57]

GREAT write up quick question i have 2hi and 4lo no problem but i cant get 4hi sometimes it says its in 4 hi but no front axle movement... any insite? btw i have the instra trac 3 button push

[96SSS10]

I'm so happy i found this thread.... My only question is why the hell did they have to put a stupid push button selector for 4X4. I was just fine with the huge shifter lever that is in the full size chevy's.... it seems to be alot more reliable..

[Donahue]

Quote: Originally Posted by bubbagt57

GREAT write up quick question i have 2hi and 4lo no problem but i cant get 4hi sometimes it says its in 4 hi but no front axle movement... any insite? btw i have the instra trac 3 button push

sounds like a bad actuator. does the front axle engage in low range?

[Donahue]

Quote: Originally Posted by 96SSS10

I'm so happy i found this thread.... My only question is why the hell did they have to put a stupid push button selector for 4X4. I was just fine with the huge shifter lever that is in the full size chevy's.... it seems to be alot more reliable..

for the yuppies. not all s10's had the push button, i saw a right up somewhere about converting the 233 to manual shift using a factory cable shifter from like a 2000. i know they were out there, but finding one is another matter.

[96SSS10]

Sorry, I been riding these trucks for awhile, so i have a good knowledge, but I'm new to the 4X4 world.

I recently got this 98 GMC Sonoma and its already giving me problems.
Mine is stuck in 4Lo. I tried the battery trick, and then pulled the battery out. When I pulled the vac line from the actuator, I saw it move. I would guess it was a release of the actuator?

I plan on replacing some vacuum lines near the brake booster because they look severely dry rotted. Would anyone have or know where I could find a diagram of the whole vac system? I can't seem to find where mine go to. It seems like they are hidden right on top of the transfer case..... damn

All help appreciated!!

[bubbagt57]

yeah my front axle engages in 4lo any clue?

[96SSS10]

From reading my haynes manual, they are vague but it seems like they're hinting that you can remove the center console and get the transfer case

This true? If so Yipiee!

[Donahue]

Quote: Originally Posted by 96SSS10

From reading my haynes manual, they are vague but it seems like they're hinting that you can remove the center console and get the transfer case

This true? If so Yipiee!

not on my truck.

[3133796s10]

ok im not sure if this belongs here but im sure someone will help me out i have a 96 s10 with a 350 sbc with a 700r4 trans well the guy who done the swap riped the computer out so none of my gauges work or ne other electronics for that matter so the fourwheel drive engagement is now a manual on the floor which is not hooked up to the front axel
he said something about a cable?
i need my fourwheeler drive!!!! i keep having to get my 79 ford f250 project out to pull my s10 out of a sticky situation lol i get to cocky at times

[Donahue]

Quote: Originally Posted by 3133796s10

ok im not sure if this belongs here but im sure someone will help me out i have a 96 s10 with a 350 sbc with a 700r4 trans well the guy who done the swap riped the computer out so none of my gauges work or ne other electronics for that matter so the fourwheel drive engagement is now a manual on the floor which is not hooked up to the front axel
he said something about a cable?
i need my fourwheeler drive!!!! i keep having to get my 79 ford f250 project out to pull my s10 out of a sticky situation lol i get to cocky at times

likely the new t-case is not sending a VSS signal to the gauges. what t-case is it? why cant you just put in a driveshaft and have 4wd?

[Morgan89]

Ohhhh.....so THATS what that chewed up black tube looking thing is hanging from the tcase! No wonder it isnt working. I have all of my experience based on an 88 GMC Jimmy k5 with an NP208 and locking hubs...a little less complicated than the s10. I figured that black tube was the breather.

THANKS for the write up!! I hadnt checked the 4wd section untill now, posted under tranny and rearend.


May I post(copy/paste) this writeup under tech at www.wheelindixie.com with credits to you and a link, or can I post just a link? Pm or reply, thanks! I know we have a couple of people with S10s and 88-98s.

Morgan

[89-S-Dime]

[quote=crazy91s10;4719144^^That chick is prolly thinkin... "Man, whatta loser"

![/quote]

[Morgan89]

I pulled on the diaphram sucking the cable out an inch till it stopped....the yoke still isnt turning by rolling the truck forward and back.

What does the electrical plug on the back of the differential do?

[Morgan89]

Ok...Plug I was looking at was actually not on the diff, it was dark lol.

I found out what the problem is(for the 3rd time)

Not only was the vaccume line busted/hanging, the plug was on the wrong way on the tcase, AND, AND, the line pulled out of the front diff...I immagine something is sposed to be connected to the arrowhead tip of the cable? *sigh*

Now I gotta rip apart all that crap on the diff... ghey. I suspect next I will find that my ring and pinion is borken, or missing. LOL. I should probably make sure my CV's are bolted on!

Would a haynes manual cover this? I have not bought one because everytime i reference one for help...it fails me.

On a positive note, crawling around under the truck I found I have a front tow hook...it was hiding below my push bar. I had to get a friend to lift up on the front push bar to get me out from under the front, LOL.

[96SSS10]

I apologize... another bad encoder motor.

[Fishnic]

Quote: Originally Posted by Donahue

age usually. the actuator should work as long as the diaphragm is intact.

put the second vacuum truck into my truck and now i have no 4x4 at all. Yesterday it worked, but made naois, today new trasfer switch, lights go on on selectors, but front tires do not spin

[Donahue]

Quote: Originally Posted by Fishnic

put the second vacuum truck into my truck and now i have no 4x4 at all. Yesterday it worked, but made naois, today new trasfer switch, lights go on on selectors, but front tires do not spin

did you get the lines on the new transfer case switch correct? i am assuming you are talking about the little one that threads into the t-case with the 3 vacuum lines coming off it.

[Fishnic]

my noise is a clicking one. i pulled the vacuum switch. the bottom has a metal ball that goes in and out. does this ball move from the vacumm pull from the top? or does is it mechanically pushed up from inside the t-case, thus switching the rout of the vacuum thru the three ports on top of it.


my trucks 4wd works fine, i have a hissing noise from behind the heater controls, and this annoying clicking sound on take off from under driver near t-case. I have changed this switch twice. My thoughts are that something that is actuating this switch is not working properly. either vacuum loss from behind the heater control, or if it is mechanically switched, something wrong inside transfer case.

Anyone know where i can get an exploded view of the t-case?

[Donahue]

Quote: Originally Posted by Fishnic

my noise is a clicking one. i pulled the vacuum switch. the bottom has a metal ball that goes in and out. does this ball move from the vacumm pull from the top? or does is it mechanically pushed up from inside the t-case, thus switching the rout of the vacuum thru the three ports on top of it.


my trucks 4wd works fine, i have a hissing noise from behind the heater controls, and this annoying clicking sound on take off from under driver near t-case. I have changed this switch twice. My thoughts are that something that is actuating this switch is not working properly. either vacuum loss from behind the heater control, or if it is mechanically switched, something wrong inside transfer case.

Anyone know where i can get an exploded view of the t-case?

that ball in mechanically manipulated from inside the case, by the shifter plate. its a two way switch, sending vacuum to one of two lines (the third is the vacuum source). i would say it would be virtually impossible for the part that manipulates the ball to break, its roughly semi circular, pivoting from a fixed point. its a few inches in radius and about 1/4" thick.

on a side note, have you checked the drive line u-joints for the clicking noise?

[Fishnic]

joints dont have any slop

clicking is now changing every so often from the click to a chirp. the original chirp i heard a few months ago and I switched out the 4x4 vacuum switch which made the noise disappear. now the noise is back along with the click. i swapped out the 4x4 vac switch and nothing has changed. i really think it is the ball clicking in and out of place at certain rpms/speeds.

I really only get the clicks upon initial acceleration from a dead stop. if it is a very slow gradual acceleration i get nothing. after rpms/speed raises, no clicks upon acceleration or anything.

[Fishnic]

Quote: Originally Posted by Donahue

that ball in mechanically manipulated from inside the case, by the shifter plate. its a two way switch, sending vacuum to one of two lines (the third is the vacuum source). i would say it would be virtually impossible for the part that manipulates the ball to break, its roughly semi circular, pivoting from a fixed point. its a few inches in radius and about 1/4" thick.

on a side note, have you checked the drive line u-joints for the clicking noise?

what makes this circular part pivot? and

[Fishnic]

Quote: Originally Posted by Donahue

that ball in mechanically manipulated from inside the case, by the shifter plate. its a two way switch, sending vacuum to one of two lines (the third is the vacuum source). i would say it would be virtually impossible for the part that manipulates the ball to break, its roughly semi circular, pivoting from a fixed point. its a few inches in radius and about 1/4" thick.

on a side note, have you checked the drive line u-joints for the clicking noise?

what makes this circular part pivot? and what makes it release?

[Ilikemice]

Up until recently I had no 4x4. Turns out one of the lines to the T-case was broken. I patched that up and put it all back together and now the actuator engages whether I'm in 4hi, 4lo or 2hi. I'm guessing my switch is dodgy, or the ball thing is. Does it just unscrew from the top of the transfer case?

[Donahue]

Quote: Originally Posted by Ilikemice

Up until recently I had no 4x4. Turns out one of the lines to the T-case was broken. I patched that up and put it all back together and now the actuator engages whether I'm in 4hi, 4lo or 2hi. I'm guessing my switch is dodgy, or the ball thing is. Does it just unscrew from the top of the transfer case?

yes, it just unscrews.

[Donahue]

Quote: Originally Posted by Fishnic

what makes this circular part pivot? and what makes it release?

the shifter makes the circular part pivot, and release.

[2THPIC]

well i got the dime home today so i'll post some pics tomarrow so maybe you guys can see what i'm up against. so fare it looks like it might be a ez fix for a daily driver. the only thing that is not working yet is it has not spark. it's getting gas and truns over but no spark. nothing is comming out of the coil. i replaced it with another one but still no luck. then i noticed that it has one of thoes white 2 prong retangle things that some how hooks up the the wireing some how. the same kind that is on older chevys like early an last 70 type models that wason the fire wall. it some hoe ties into the points system but that doesn't seam right this is a 86 model s10.did thay have points in these?

[Donahue]

its HEI

[2THPIC]

Quote: Originally Posted by Donahue

its HEI

yea, but it's not oem. some one had replaced it with a Mallory distributor setup and it was all rigged together and done crappy. i want to pull all that stuff out and replace it with oem. that a way there's no b.