1998 Chevy 4x4 Problems

[Eazy]

Having some problems with the 4x4 on my chevy 1/2 ton lately........It's of the push-button varient, and when I push the 4x4 button the little light just keeps flashing and therefore no engagement. After doing some minimal research it seemed that the "actuator" may be the culprit? Any advice would be helpful.....Thanks!

[BillM]

Yup, most likely the actuator located under the battery tray. You'll also wanna check the plug on the transfer case that teh vac lines go into.

Edited June 20, 2011 by BillM

[Eazy]

Yup, most likely the actuator located under the battery tray. You'll also wanna check the plug on the transfer case that teh vac lines go into.

[Eazy]

Hmmm....actuator on mine is on the passenger side of the front differential.

[BillM]

Interesting.. They all do the same thing regardless Diaphragm is most likely torn.

 

Put a MityVac on it before hand to make sure that the sleeve engages in the front diff.. If it does, you've most likely found your problem.

Edited June 20, 2011 by BillM

[SBCregal]

take a good look around for a busted vac line too

[Eazy]

take a good look around for a busted vac line too

Do the push-button 4x4's rely on vacuum, because I only have a wiring harness running down to my actuator?

[Pasquale]

I believe the problem is the Encoder motor (actuator) which is mounted to the side of the transfer case. I have replaced a ton of these's at the dealer. 99% of the time thats what its is. The odd time there is a wiring problem or a faulty shift control module but more than likely it will need a new Encoder motor. Pretty costly just for the part. I have seen them range from $400 to $1200 and depending on the mechanic working on your truck labour ranged from 1/2 hrs to 2hrs. I hope this info helps.

[bdox]

When my '01 chevy did the same thing (blinking lights) it was a rotten vacuum line going to the actuator under the battery tray. Mine might be a different setup though, it was 4 button auto-trac.

[Eazy]

I believe the problem is the Encoder motor (actuator) which is mounted to the side of the transfer case. I have replaced a ton of these's at the dealer. 99% of the time thats what its is. The odd time there is a wiring problem or a faulty shift control module but more than likely it will need a new Encoder motor. Pretty costly just for the part. I have seen them range from $400 to $1200 and depending on the mechanic working on your truck labour ranged from 1/2 hrs to 2hrs. I hope this info helps.

 

Thats what I figured, picked up the part online for $89.95(USA), and they even had a little video to show you how to do it!....If you can change a sparkplug on an outboard you can do this job!.......If thats not it, I'll be consulting a mechanic.

[smally21]

if we're talking about the little worm gear module on the transfer case that was the culprit on my chevy it was 135$ and about 5 minutes. you can test it with a meter or a 12 volt source.

[Eazy]

Changed the Actuator which didn't cure the problem .........further investigation revealed that a stick that had gotten stuck in the under-carriage somehow managed to shear off the transfer case actuator .....bought a new one of these and installed it, problem fixed!