Replace front axle 4x4 drive actuator

[isd503]

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



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.



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.

Is there any way to verify both the front and rear axles without cracking the case? The markings on the outside are not sufficient information to verify ratio?

 

[isd503]

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



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.



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.

What is the process to verify? I thought the axle part markings would do the trick, but that has not worked. I've got 10 bolts on the back and front differentials. I would like to have certainty regarding the axles and ratios if possible.

 

[Caman96]

What is the process to verify? I thought the axle part markings would do the trick, but that has not worked. I've got 10 bolts on the back and front differentials. I would like to have certainty regarding the axles and ratios if possible.

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Do you have any reason to not believe what your rpo code says in glove box?

 

[isd503]

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Do you have any reason to not believe what your rpo code says in glove box?

I don't know. I bought the truck used with 290,000 + miles on it. Both axles are probably the originals, but I would like to make sure of that before troubleshooting other problems like low power. When I say axle, I am referring to the whole thing from wheel to wheel.

 

[Caman96]

I don't know. I bought the truck used with 290,000 + miles on it. Both axles are probably the originals, but I would like to make sure of that before troubleshooting other problems like low power. When I say axle, I am referring to the whole thing from wheel to wheel.

The video was just an example, you can do that with your tires on. Your front and rear will be the same ratio.
Have you ever driven it in 4WD? Confirm your rear axle as shown in video and there’s a really good chance it will match your rpo code.
GU4 = 3.08
GU5 = 3.23
GU6 = 3.42
GT4 = 3.73
GT5 = 4.10(thank you @df2x4)