Replace front axle 4x4 drive actuator

[df2x4]

As mentioned previously, the old thermal actuators are still available. Just not from GM directly. RockAuto has several options available, you just need to make sure you observe which type of terminals your existing connector has so you order the correct type.

https://www.rockauto.com/en/catalog...5.7l+v8,1158241,drivetrain,4wd+actuator,10456

 

[df2x4]

Also, is there any way to determine the ratio using this information?

Would be much easier to just check the RPO code sticker in the glove box if it's still intact.

GU4 = 3.08
GU5 = 3.23
GU6 = 3.42
GT4 = 3.73
GT5 = 4.10

 

[isd503]

Thank you for all this information. It is very helpful. The reason I didn’t post the RPO code was because I thought it only applied to the rear axle. From what some of you are writing, it sounds like it applies to both the rear and the front axle. Is that true?

Is there any way to independently verify the ratio of the front axle without breaking it open? The reason I ask is because it is possible on these old trucks that someone replaced one and it is not factory.

Also, my preference has always been to use GM parts first unless I cannot get it anymore.

The RPO code for my rear axle is GT4/G80, 3.73. The RPO code for the front axle is YD3 and I have not been able to find anything on it. My glove box is aftermarket so I had to contact the GM Archives and buy the build sheet and RPO code list.

 

[Caman96]

"Signatures" don't show up on mobile devices.

I second what @Caman96 stated. Help us help you...

This is the worm gear adaptor I bought for my '88 to eliminate the worn out TLA

FITS 88-96 GMC CHEV K1500 K2500 K3500 UPGRADE 4WD ACTUATOR & WIRING KIT | eBay

WARRANTYWarranty Duration: 1 Year. WHAT SIDE PART DO I NEED?. RIGHT is the PASSENGER SIDE. LEFT SIDE is the DRIVER SIDE. We don't want you to be disappointed by getting the incorrect side part. Part #: 600-490.

www.ebay.com

Is it the pre-96”s that need the harness and actuator and 96+ just the actuator?

 

[Caman96]

it applies to both the rear and the front axle

Yes, both have to be the same ratio.

 

[BNielsen]

Is it the pre-96”s that need the harness and actuator and 96+ just the actuator?

96 and below needs the conversion harness. 96 was the last year for the thermal actuator; 97 and up was electric

 

[isd503]

Yes, both have to be the same ratio.

I thought the pictures with the codes in them would be sufficient to identify the front axle?

 

[isd503]

When I see this: Front Drive Axle Actuator - 26060073 (2nd design, stamped ZKS, ZLW, ZXS, ZLY, ZXN, UM1, ZD2, ZWA, ZWB), are the stamps on the actuator or the axle?

Is there any key for these stamps?

 

[df2x4]

97 and up was electric

FWIW, my '97 K1500 Suburban (built in December of '96) still uses a thermal actuator. It may have been a mid-year '97 thing.

When I see this: Front Drive Axle Actuator - 26060073 (2nd design, stamped ZKS, ZLW, ZXS, ZLY, ZXN, UM1, ZD2, ZWA, ZWB), are the stamps on the actuator or the axle?

Is there any key for these stamps?

Not sure about the stamps, but I believe the actuators are all pretty much the same. Either you have one of the thermal style with two blade (or two round) terminals in the connector, or you have the newer electric style with the five pin connector.

If you want to convert from a thermal to an electric actuator you'll need the electric actuator itself and the Dorman wiring/spacer kit, part number 600-600. Note that this kit is only plug and play with the round terminal connector style thermal actuators, you may have to modify the harness and splice in the connector from your existing actuator if you have the two blade terminals.

EDIT - It looks like Dorman also has a complete conversion kit including the electronic actuator, harness, and spacer. Part number 600-490.

The reason I didn’t post the RPO code was because I thought it only applied to the rear axle. From what some of you are writing, it sounds like it applies to both the rear and the front axle. Is that true?

From the factory it definitely applies to both, as they need to match. If this truck is new to you and you haven't tested the 4WD, then it would be a good idea to verify.

 

[Caman96]

96 and below needs the conversion harness. 96 was the last year for the thermal actuator; 97 and up was electric

You must be registered for see images attach

This seems to indicate that 96 and up you don’t need the harness.
Edit: But it’s Dorman, I just checked and I have the 2-wire on my 96.