Four wheel drive actuator slow to engage

[98chevy2500SS]

On my 97 I noticed it takes about 8 seconds for it to engage into 4x4. My 98 only takes 2 seconds tops to engage, is it the actuator that needs replaced? Both have the push button, would like my 97's 4x4 to engage sooner.

I scrapped my 98's half ton diff and saved the actuator off of it, it has the 5 pin, so I assume it's the electric, do the 97's have the electric too or did they have the thermal actuator? I am hoping it doesn't have the thermal one.

Thanks.

 

[HotrodZ06]

My wife's 2000 Escalade was taking a bit longer than i thought it should to shift to different ranges and then it just got stuck in neutral and wouldn't shift. The shift motor on transfer case was the faulty part on mine. If you have a way to read transfer case codes mine set a circuit code for the transfer case encoder motor then I followed the diagnostic tree in the service manual said to replace encoder motor and now it shifts quickly and positively. I haven't had any trouble with front axle actuators other than the old 2 wire gas charged ones so I can't say what that might do. Hope this helps.

 

[alpinecrick]

I'm not aware of any of the GMT400 K1500's or K2500"s that originally came with the electric actuator?

You're not saying if SUV or pickup. The thermal actuators will vary in how long it takes to engage the front axle, so I don't think the difference is an indication of the actuator going out.

The aftermarket electric actuators on my 96 and 97 pickups engage instantly.

 

[HotrodZ06]

If it is push button 4x4 it has an encoder motor on the transfer case several GMT400s had them. As far as the front axle actuator i can't remember if it was 97 or 98 they stated coming with the 5 wire electric motor actuator. I know my 98 K2500 has the 5 wire electric motor actuator from the factory and my 96 K1500 had the thermal actuator from the factory it was slow to engage but eventually went out and replaced it with the GM retrofit harness and GM 5 wire actuator.

 

[df2x4]

I'm not aware of any of the GMT400 K1500's or K2500"s that originally came with the electric actuator?

I believe starting about halfway through '97 they switched to the electronic actuators, but I could be wrong. Others here have said that their '97s came with the electronic style, but my '97 Suburban is thermal.

@98chevy2500SS I'd say what you're probably noticing is the difference in actuation time between the thermal and electronic actuators. If you crawl under the trucks and look at the visible halves of the actuators (and their plugs/wiring harnesses) I bet they look different.

 

[98chevy2500SS]

Finally got some free time today to go take a look under the truck, and of course, it's the thermal actuator. I was researching that there is a harness that converts it from thermal to electronic, but it's almost the amount of money just to buy another thermal one, would it be worth it to switch over or should I just stick with the thermal one?

It's weird how when we were converting my 98 to the 3/4 ton stuff, the actuator was already electric on the 95 diff, so I'm not sure if it was converted on that truck or maybe it was that way from the factory?

 

[HotrodZ06]

95 should have been thermal from the factory. A previous owner probably converted it or had it converted. I would go with the electric if possible works so much better.

 

[df2x4]

I was researching that there is a harness that converts it from thermal to electronic, but it's almost the amount of money just to buy another thermal one, would it be worth it to switch over or should I just stick with the thermal one?

I researched the same thing when the thermal one in my Suburban went out but ended up just replacing it with another thermal. I have no regrets. I'm sure it takes a little longer than the electronic ones to engage, but I've never had it pop out on me or do anything unexpected and I've beat on the truck pretty hard in the snow.

 

[98chevy2500SS]

I researched the same thing when the thermal one in my Suburban went out but ended up just replacing it with another thermal. I have no regrets. I'm sure it takes a little longer than the electronic ones to engage, but I've never had it pop out on me or do anything unexpected and I've beat on the truck pretty hard in the snow.

Do you remember how long your new actuator takes to engage?

 

[alpinecrick]

Finally got some free time today to go take a look under the truck, and of course, it's the thermal actuator. I was researching that there is a harness that converts it from thermal to electronic, but it's almost the amount of money just to buy another thermal one, would it be worth it to switch over or should I just stick with the thermal one?

It's weird how when we were converting my 98 to the 3/4 ton stuff, the actuator was already electric on the 95 diff, so I'm not sure if it was converted on that truck or maybe it was that way from the factory?

I'm thinking your 95 axle was converted.

The thermal actuators do tend go out at the most inopportune times. Which is why god (or GM) invented the electric actuators.

The electric actuators do NOT like to be immersed in water--I know this--and it was just a series of very large mud puddles that killed it. Its easy to see why, the seam where the two halves are joined is not sealed. What brilliant engineer left that little detail out is beyond me.

I epoxied the seam of the electric actuators on both my trucks and then put a zip tie around the seam. So far so good, they have both been on there for a couple years.

The thermal actuators delayed engagement drive me nuts. I could practically get out and turn a pair of hubs in the same time span, I swear.....