4X4 does'nt disengage right

pit_boss · 01-16-2007, 07:28 PM

Ive got a 95 S10 Blazer, the 4WD engages smooth,but when you disengage it sometimes it doesnt immediatly disengage, and when it does it, it lets out an awfull clunk,it has the electronic push buttons, and is a 4.3 w/AT. Thanks! Jim

791ton · 01-16-2007, 07:36 PM

lol sounds normal to me. all my 4x4 blazers have done that, i never thought of it as a problem

klink70 · 01-16-2007, 08:31 PM

With that push button set-up, you,ve got a vaccum switch at the transfer case. This vaccum switch puts suction on a diaphram located under the battery tray. That diaphram pulls a cable to engage the front axle. Maybe the return spring in the diaphram is broke or weak or the cable is corroded and doesn't move freely. If thats not it then it has to be something with the electric motor on the transfer case that shifts the case into and out of 2-hi, 4-hi, and 4-low. My wifes '98 always clunks when shifted from 2-hi or 4-hi to 4-low.

will4831 · 01-16-2007, 08:43 PM

anybody know if a push button 4x4 '94 s-10 blazer has the same problem? I have a vacuum line in the same area, but it is unhooked. i rebuit the front after a deer did it in, but can't seem to see where that line goes...

pit_boss · 01-17-2007, 07:42 AM

Quote:

Originally Posted by klink70

With that push button set-up, you,ve got a vaccum switch at the transfer case. This vaccum switch puts suction on a diaphram located under the battery tray. That diaphram pulls a cable to engage the front axle. Maybe the return spring in the diaphram is broke or weak or the cable is corroded and doesn't move freely. If thats not it then it has to be something with the electric motor on the transfer case that shifts the case into and out of 2-hi, 4-hi, and 4-low. My wifes '98 always clunks when shifted from 2-hi or 4-hi to 4-low.

I had a bad diaphram under the battery tray at one time, before I figured that out ,I had replaced the switch on the transfer case, so now that you mention the cable I'll check that out,Hope it's not the motor, thanks for your help ! Jim

klink70 · 01-19-2007, 08:17 AM

Quote:

Originally Posted by will4831

anybody know if a push button 4x4 '94 s-10 blazer has the same problem? I have a vacuum line in the same area, but it is unhooked. i rebuit the front after a deer did it in, but can't seem to see where that line goes...

It's probably the same set-up as mentioned before. Does the front axle engage? Lock it in and slowly turn the vehicle sharply in both directions, if the front end wants hop or jump then it's engaging the front axle. If it's not engaging, then I would check that vacuum line. With the engine running engage the transfer case(4hi or 4low) and check the hose for suction with your finger. Check the diaphram under the battery tray to see if it has a hose connected to it, if it doesn't, then that's probably where that hose is supposed to go. Remember, that hose should only have suction on it when the t-case is engaged. If that doesn't work check the main vacuum line running to the t-case from a good vacuum source, it's probably on the intake somewhere. That line should have suction on it any time the engine is running. The vacuum switch on the t-case channels that suction to the hose running back to the diaphram to engage the f-axle. Another way around that whole vacuum set-up is to hook a cable up directly to the axle and mount it in the cab with a t-handle. Engage the transfer case and pull the cable, and a-wheelin' you will go.

chevyguy · 01-21-2007, 12:18 AM

its normal. Dont worry about it.

01-16-2007, 07:28 PM	#1
pit_boss Full Member Join Date: Dec 2006 Location: Hartland,Minnesota Posts: 25	4X4 does'nt disengage right Ive got a 95 S10 Blazer, the 4WD engages smooth,but when you disengage it sometimes it doesnt immediatly disengage, and when it does it, it lets out an awfull clunk,it has the electronic push buttons, and is a 4.3 w/AT. Thanks! Jim Last edited by pit_boss; 01-17-2007 at 07:45 AM.

01-16-2007, 07:36 PM	#2
791ton Senior Member Join Date: Dec 2006 Location: Bremerton, Washington Posts: 64	lol sounds normal to me. all my 4x4 blazers have done that, i never thought of it as a problem __________________ 1979 Crew Cab Chevy 1 Ton Dually 454

01-16-2007, 08:43 PM	#4
will4831 Senior Member Join Date: Feb 2006 Location: South Dakota Posts: 127	anybody know if a push button 4x4 '94 s-10 blazer has the same problem? I have a vacuum line in the same area, but it is unhooked. i rebuit the front after a deer did it in, but can't seem to see where that line goes... __________________ '96 GMC 1500 Victory Red x-cab *4x4* Programmed 350 crying for a rebuild '88 IROC-Z Camaro 5.0 5speed t-tops stock...not for long '93 Escort GT 1.8 DOHC 127hp 5speed. Daily Driver/Beater

01-21-2007, 12:18 AM	#7
chevyguy Senior Member Join Date: Sep 2005 Location: ALABAMA Posts: 3,370	its normal. Dont worry about it. __________________ Friends dont let friends use body lifts USMC 92-96 USCG 98 to present

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01-16-2007, 08:31 PM	#3
klink70 Full Member Join Date: Dec 2005 Posts: 14	With that push button set-up, you,ve got a vaccum switch at the transfer case. This vaccum switch puts suction on a diaphram located under the battery tray. That diaphram pulls a cable to engage the front axle. Maybe the return spring in the diaphram is broke or weak or the cable is corroded and doesn't move freely. If thats not it then it has to be something with the electric motor on the transfer case that shifts the case into and out of 2-hi, 4-hi, and 4-low. My wifes '98 always clunks when shifted from 2-hi or 4-hi to 4-low.