Just got back from the shop and they told me that a switch on the transfer case was suck on and it burned out the front actuator in the differential. I was gona have them do it but they said that they changed the style of the actuator and I would need a new wiring harness. I not going to replace a working wiring harness so I was wondering if anyone has changed an actuator(how to do it), where to get an old style one and around how much $ they are.
Front differential actuator install?
- Thread starter magnahoe
- Start date
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blueflamed03
Elite Member
Technical Service Bulletin
File In Section: 4 Drive Axle
Bulletin No.: 76-43-01A
Date: September, 1998
Subject:
Slow or no Engagement of Front Axle when 4WD is selected (Replace Front Axle Actuator)
Models:
1988-97 Chevrolet and GMC K Models
excluding 1988-93 Models over 8500 # GVW
This bulletin is being revised to add information to the Service Procedure, add a new part number, and include schematics. Please discard Corporate Bulletin Number 76-43-01 (Section 4 - Drive Axle).
Condition
Some owners may comment that the colder the outside temperature is, the longer it takes for the front axle to engage when 4 wheel drive is selected, or the front axle does not engage.
Cause
The front axle engagement actuator is a thermally activated component. Because of this characteristic, the time required for the actuator to complete 4 wheel drive engagement is extended as the temperature drops.
Correction
Replace the front axle actuator and include the applicable wiring harness kit. Refer to the Parts Information in order to determine which wiring harness kit is needed.
1996 model trucks with a build date on or after January 2, 1996 are considered as "961". If the build date of the truck is unknown, verify the 3 character "axle code" on the front axle label in order to determine which wire harness to order.
This new actuator uses a motor to engage the front axle and is not affected by temperature. On 1988-93 models with a GVW rating over 8500$, the new actuator cannot be installed and the thermal actuator will remain the service part.
26060073 Actuator Asm, Frt Drive Axle 1
Remove or Disconnect
Skid plate (if equipped).
Electrical connector from the indicator switch located on the upper right side of the differential.
Indicator switch (11).
Install or Connect
Indicator switch (11).
Coat the switch thread with sealer (GM P/N 1052942) or equivalent.
Electrical connector.
Skid plate (if equipped).
File In Section: 4 Drive Axle
Bulletin No.: 76-43-01A
Date: September, 1998
Subject:
Slow or no Engagement of Front Axle when 4WD is selected (Replace Front Axle Actuator)
Models:
1988-97 Chevrolet and GMC K Models
excluding 1988-93 Models over 8500 # GVW
This bulletin is being revised to add information to the Service Procedure, add a new part number, and include schematics. Please discard Corporate Bulletin Number 76-43-01 (Section 4 - Drive Axle).
Condition
Some owners may comment that the colder the outside temperature is, the longer it takes for the front axle to engage when 4 wheel drive is selected, or the front axle does not engage.
Cause
The front axle engagement actuator is a thermally activated component. Because of this characteristic, the time required for the actuator to complete 4 wheel drive engagement is extended as the temperature drops.
Correction
Replace the front axle actuator and include the applicable wiring harness kit. Refer to the Parts Information in order to determine which wiring harness kit is needed.
1996 model trucks with a build date on or after January 2, 1996 are considered as "961". If the build date of the truck is unknown, verify the 3 character "axle code" on the front axle label in order to determine which wire harness to order.
This new actuator uses a motor to engage the front axle and is not affected by temperature. On 1988-93 models with a GVW rating over 8500$, the new actuator cannot be installed and the thermal actuator will remain the service part.
26060073 Actuator Asm, Frt Drive Axle 1
Remove or Disconnect
Skid plate (if equipped).
Electrical connector from the indicator switch located on the upper right side of the differential.
Indicator switch (11).
Install or Connect
Indicator switch (11).
Coat the switch thread with sealer (GM P/N 1052942) or equivalent.
Electrical connector.
Skid plate (if equipped).
Attachments
loulblades
Full Access Member
Replacing the actuator itself is a pretty simple job.
Remove the connector.
Unscrew the actuator.
Put some goo(thread sealer) on the threads of the new actuator if it doesn't already have it.
Screw in the actuator.
Plug in connector.
Replacing the transfer case switch (if the dealer didn't do it) will take more time.
I saw a thermal actuator at the Autozone website when I was looking for one for a 97 tahoe but don't know for absolute certainty that it is the right one (axle codes).
If you are anywhere that it is cold it is well worth doing the TSB. I like not having to wait for the 4WD to engage when I am running through the woods in winter.
Remove the connector.
Unscrew the actuator.
Put some goo(thread sealer) on the threads of the new actuator if it doesn't already have it.
Screw in the actuator.
Plug in connector.
Replacing the transfer case switch (if the dealer didn't do it) will take more time.
I saw a thermal actuator at the Autozone website when I was looking for one for a 97 tahoe but don't know for absolute certainty that it is the right one (axle codes).
If you are anywhere that it is cold it is well worth doing the TSB. I like not having to wait for the 4WD to engage when I am running through the woods in winter.
Yeah, picked one up at the junk yard for $65, going to have the shop do the switch. would have had them do it all but they wanted $220 for the actuator just in parts. They also wanted $120 for a new wiring harness due to change in style.
Last edited:
ravingmadman
Chief Knuckle Buster
Wow. Screw that. Good job minimizing your exposure there.
bsamoul
Hoe Enthusiast
Does anyone know where the wiring harnesses are sold other than the dealer?
---------- Post added at 03:05 PM ---------- Previous post was at 03:00 PM ----------
http://www.getdieselpower.com/misc_auto/actuator_upgrade/GM_TRUCK_4X4_ACTUATOR_UPGRADE.html
---------- Post added at 03:05 PM ---------- Previous post was at 03:00 PM ----------
http://www.getdieselpower.com/misc_auto/actuator_upgrade/GM_TRUCK_4X4_ACTUATOR_UPGRADE.html
ravingmadman
Chief Knuckle Buster
Every time I've gotten a part that required a new harness (fuel pump was most recent), it came with both male and female ends, if it was a necessary upgrade per a tech bulletin. Not sure if this one will have both sides or not...
Just found out the shop was trying to rip me off I went to Napa before I got the part from the junkyard and found out the most expensive actuator they carry is $150 and just found an adapter for $22. I know they have markup on parts but thats a $170 difference. I have been going to this shop since I got the truck, and have probably done $1500 worth of business with them, and have never had a problem but I don't think I will be going there again. I was pissed that they charged me even though I give them a lot of business and I told them that it was probably the actuator in the first place.
Cmdrpopnfresh
TYF Newbie
- Joined
- Dec 12, 2009
- Posts
- 14
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anyone know if any of these acctuators are the updated actuators that are not the thermal kind?
autozone acctuators
my 4x4 went out this morning and i think its the diff actuator. the 4hi light just flashes after i push the button and i have no 4x4.
thanks for any help
---------- Post added at 01:15 PM ---------- Previous post was at 12:41 PM ----------
wait now im confused. does my 97 have the thermal type actuator? or the motor? cause it seems like that tsb applies but i cant seem to find any info about replacement actuators....they all look like the motor type.....could someone clear this up for me? do i need to do the updated part?
autozone acctuators
my 4x4 went out this morning and i think its the diff actuator. the 4hi light just flashes after i push the button and i have no 4x4.
thanks for any help
---------- Post added at 01:15 PM ---------- Previous post was at 12:41 PM ----------
wait now im confused. does my 97 have the thermal type actuator? or the motor? cause it seems like that tsb applies but i cant seem to find any info about replacement actuators....they all look like the motor type.....could someone clear this up for me? do i need to do the updated part?
Last edited:
bsamoul
Hoe Enthusiast
I'm hoping someone here can answer if the upgrade to electric from thermal will definitely fix the blinking? anyone?
ravingmadman
Chief Knuckle Buster
Wow, you got me, dude. I see your post, you are heard, I just have nothing for you. Sorry...
loulblades
Full Access Member
If you are referring to the blinking after you push the switch until the actuator engages (you see this more in cold weather), it will definitely help with that.
If you are saying that the blinking is constant after you push the switch (an indication that the 4WD didn't engage or didn't receive feedback that it did) then maybe. Depends what is wrong with the system.
yukonaetahoe
Full Access Member
man i was asking this same question like 2 months ago. im so glad to see more info on this as i just got about 4 actuators from the junk yard to see if any of them will work. and if need to upgrade to thermal or electric or whatever man ill do it in a heart beat! hope to see more info and pictures soon. good luck guys hope all is well
---------- Post added at 08:44 PM ---------- Previous post was at 08:37 PM ----------
what is a TSB
---------- Post added at 08:44 PM ---------- Previous post was at 08:37 PM ----------
what is a TSB
bsamoul
Hoe Enthusiast
Is yours blinking when you push the 4x4 buttons?
loulblades
Full Access Member
I posted a 4WD diagnostic document on another site (which I won't mention).
It is for regular electric 4WD (not Auto 4WD)
I would like to post it here but it is too big.
If anyone is interested to receive it, send me a PM with your email.
It is for regular electric 4WD (not Auto 4WD)
I would like to post it here but it is too big.
If anyone is interested to receive it, send me a PM with your email.
yukonaetahoe
Full Access Member
nope. When i shift to 4x4 my fuse blows out, and i have no light anywere. i just got two other actuators from the junk yard to swap it and see if it helps.
but if i could avoid this "heat" one and use an electrci one or whatever is more efficient im down!
I got one from the junk yard, didn't work. Just bought one from NAPA for the same price, waiting for it to be shipped. To bad we just got 2ft of snow.
Shadowace6969
TYF Newbie
- Joined
- Dec 25, 2009
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?
Having the same or similar problem. The neutral light and 2hi light come on when I start the vehicle. Eventually both lights go off, it doesn't engage when I hit the other buttons and the only light that comes on when I push them is the red neutral light. I just put in a new 4 button switch hopeing to remedy this, but same thing. I'm kinda snowed in at the moment and can't reach someone with a scantool, is there a way I can tell if its the transfer case encoder motor or the actuator / or both without a scantool? If so, I can order the parts and do the labor myself. It's a 1998 5.7 LT, It is in 2hi (neutral not actually on, since I'm able to still drive the vehicle). This snow is kickin my arse without 4x4 lol. Thanks.
Having the same or similar problem. The neutral light and 2hi light come on when I start the vehicle. Eventually both lights go off, it doesn't engage when I hit the other buttons and the only light that comes on when I push them is the red neutral light. I just put in a new 4 button switch hopeing to remedy this, but same thing. I'm kinda snowed in at the moment and can't reach someone with a scantool, is there a way I can tell if its the transfer case encoder motor or the actuator / or both without a scantool? If so, I can order the parts and do the labor myself. It's a 1998 5.7 LT, It is in 2hi (neutral not actually on, since I'm able to still drive the vehicle). This snow is kickin my arse without 4x4 lol. Thanks.
loulblades
Full Access Member
Try this.
Obtaining Diagnostic Trouble Codes
The diagnostic trouble codes are displayed on the three transfer case shift select buttons. The shift select buttons are located to the right of the instrument panel cluster. When pin 13 of the data link connector is grounded and the ignition switch has been in the OFF position for at least five seconds prior to positioning the ignition switch to the RUN position, the shift select buttons will blink a number of times in order to indicate a diagnostic trouble code from 1 to 4.
Position the ignition switch to OFF. Ensure the ignition switch is positioned to OFF for at least 5 seconds.
Connect pin 13 on the data link connector to a vehicle ground source. The data link connector is located in the cab under the instrument panel on the drivers side.
Position the ignition switch to RUN.
Note the shift select buttons for blinking codes. Refer to Perform a Diagnostic on the TCCM.
If the shift select buttons all blink one time and stop, and do not continue to blink, no fault codes are stored in the TCCM.
The transfer case shift select buttons will blink in order to identify any stored DTC. If only one code is stored in the TCCM memory, that code will blink repeatedly with a three second delay between blinking sequences. If more than one code is stored, the first code will blink once, then after a three seconds delay, the next code will blink. This sequence will continue until pin 13 is no longer grounded.
When reading the diagnostic trouble codes, the number of shift select buttons blinks will indicate the code number.
Obtaining Diagnostic Trouble Codes
The diagnostic trouble codes are displayed on the three transfer case shift select buttons. The shift select buttons are located to the right of the instrument panel cluster. When pin 13 of the data link connector is grounded and the ignition switch has been in the OFF position for at least five seconds prior to positioning the ignition switch to the RUN position, the shift select buttons will blink a number of times in order to indicate a diagnostic trouble code from 1 to 4.
Position the ignition switch to OFF. Ensure the ignition switch is positioned to OFF for at least 5 seconds.
Connect pin 13 on the data link connector to a vehicle ground source. The data link connector is located in the cab under the instrument panel on the drivers side.
Position the ignition switch to RUN.
Note the shift select buttons for blinking codes. Refer to Perform a Diagnostic on the TCCM.
If the shift select buttons all blink one time and stop, and do not continue to blink, no fault codes are stored in the TCCM.
The transfer case shift select buttons will blink in order to identify any stored DTC. If only one code is stored in the TCCM memory, that code will blink repeatedly with a three second delay between blinking sequences. If more than one code is stored, the first code will blink once, then after a three seconds delay, the next code will blink. This sequence will continue until pin 13 is no longer grounded.
When reading the diagnostic trouble codes, the number of shift select buttons blinks will indicate the code number.
There is also an electronic switch on the t case. I would try changing that before changing the encoder motor because the switch is $14 and the encoder motor is over $200.
