2004 Z71 Silverado Front Axle Engagement

[bhazely]

I replaced my 1996 Silverado 211k (running perfectly) with a 2004 silverado with 70k on it (2 weeks ago) and launched my boat in a sandy area and my front axle would not engage in either auto, 4 high, or 4 low. The selector switch indicator seemed to function properly by blinking and then remaining solid in each selection. I could hear the rear differential sound of it engaging, but the front tires remained still. After burying the truck I got pulled out and of course fished all day and caught zero walleye. I then got stuck again removing the boat while trying every four wheel drive selection that I had and all selector switch light indicators seemed to function properly. I ohmed the two 4wd fuses that I found and they were fine. I then searched online and was clued in to the front axle actuator to be suspect and then decided to replace it. When I got the new actuator and compared it to the old actuator the inside piston looked eccentric to the outside guides so I took pictures of the old and new to compare and the old one looked concentric. The front axles still don't engage, I guess my next step should be the one that I skipped of testing to see that the actuator extends. Any tips on testing the actuators or anything else would be appreciated.

[bhazely]

I replaced my 1996 Silverado 211k (running perfectly) with a 2004 silverado with 70k on it (2 weeks ago) and launched my boat in a sandy area and my front axle would not engage in either auto, 4 high, or 4 low. The selector switch indicator seemed to function properly by blinking and then remaining solid in each selection. I could hear the rear differential sound of it engaging, but the front tires remained still. After burying the truck I got pulled out and of course fished all day and caught zero walleye. I then got stuck again removing the boat while trying every four wheel drive selection that I had and all selector switch light indicators seemed to function properly. I ohmed the two 4wd fuses that I found and they were fine. I then searched online and was clued in to the front axle actuator to be suspect and then decided to replace it. When I got the new actuator and compared it to the old actuator the inside piston looked eccentric to the outside guides so I took pictures of the old and new to compare and the old one looked concentric. The front axles still don't engage, I guess my next step should be the one that I skipped of testing to see that the actuator extends. Any tips on testing the actuators or anything else would be appreciated.

 

I removed my skid plate and tested the old actuator and the new actuator and they both extended properly, about an inch. Anyone have any ideas on my next step?

[Matt_]

Actuator extends, but how much force? May still need a new actuator.

 

Put the truck in 4wd, and in park. Chock the rear tires, raise the front. Spin the driver side tire. Does the passenger side spin the opposite direction?

[bhazely]

Actuator extends, but how much force? May still need a new actuator.

 

Put the truck in 4wd, and in park. Chock the rear tires, raise the front. Spin the driver side tire. Does the passenger side spin the opposite direction?

 

 

I will do this, not questioning you, just trying to understand why?

[Matt_]

If the front diff engages, the passenger tire will spin in the opposite direction (as long as the driveshaft doesn't spin, which is shouldn't if in Park while in 4x4.. if it does, theres your issue).

 

If the front diff doesn't engage, you'll only spin the spider gears and the passenger tire wont rotate. It's a quick/easy test to see if the actuator is working.

[bhazely]

If the front diff engages, the passenger tire will spin in the opposite direction (as long as the driveshaft doesn't spin, which is shouldn't if in Park while in 4x4.. if it does, theres your issue).

 

If the front diff doesn't engage, you'll only spin the spider gears and the passenger tire wont rotate. It's a quick/easy test to see if the actuator is working.

 

Makes sense now, be back in 15 minutes. Thanks for the advice.

[Matt_]

No prob.

 

Here's a thread on the breakdown of how it works: http://www.gm-trucks.com/forums/index.php?...amp;hl=actuator

[bhazely]

If the front diff engages, the passenger tire will spin in the opposite direction (as long as the driveshaft doesn't spin, which is shouldn't if in Park while in 4x4.. if it does, theres your issue).

 

If the front diff doesn't engage, you'll only spin the spider gears and the passenger tire wont rotate. It's a quick/easy test to see if the actuator is working.

 

Makes sense now, be back in 15 minutes. Thanks for the advice.

 

 

In park with 4wd "engaged" I spin the drivers side tire and the passenger

side tire doesn't rotate. When I spin the passenger side tire, the drivers side spins the opposite direction.

[bhazely]

If the front diff engages, the passenger tire will spin in the opposite direction (as long as the driveshaft doesn't spin, which is shouldn't if in Park while in 4x4.. if it does, theres your issue).

 

If the front diff doesn't engage, you'll only spin the spider gears and the passenger tire wont rotate. It's a quick/easy test to see if the actuator is working.

 

Makes sense now, be back in 15 minutes. Thanks for the advice.

 

 

In park with 4wd "engaged" I spin the drivers side tire and the passenger

side tire doesn't rotate. When I spin the passenger side tire, the drivers side spins the opposite direction.

 

 

I guess I don't understand how that rules out the shifting mechanism that is after the actuator?

[Matt_]

In park with 4wd "engaged" I spin the drivers side tire and the passenger

side tire doesn't rotate. When I spin the passenger side tire, the drivers side spins the opposite direction.

 

Doh, I should have told you to spin the passenger side first. With the actuator engaged the passenger tire usually need to rotate a few degrees so the teeth line up.

 

Did you go back and spin the drivers side again?

 

With the actuator engaged and the drive shaft locked in place, the other wheel will always spin the opposite direction. If the actuator doesn't engage, the other wheel won't rotate because the passenger side is completely disengaged from the gear set in the diff.

[bhazely]

In park with 4wd "engaged" I spin the drivers side tire and the passenger

side tire doesn't rotate. When I spin the passenger side tire, the drivers side spins the opposite direction.

 

Doh, I should have told you to spin the passenger side first. With the actuator engaged the passenger tire usually need to rotate a few degrees so the teeth line up.

 

Did you go back and spin the drivers side again?

 

With the actuator engaged and the drive shaft locked in place, the other wheel will always spin the opposite direction. If the actuator doesn't engage, the other wheel won't rotate because the passenger side is completely disengaged from the gear set in the diff.

 

 

 

I rechecked it, and after engaging the passenger side the driver's side did not rotate the passenger side. Can you explain How this rule's out the shifting mechanism for the transfer case.

[Matt_]

I explained it in my last post. It's simple, either the axle is engaged or its not (see that thread i linked previously for a breakdown of the internals and how the axle is actuated)

 

Was the drive shaft spinning at all??

 

Somethings not adding up. If you spin the passenger side tire, and the drivers side spins the opposite direction, but then you spin the drivers side, and the passenger side doesn't spin, then the driveshaft must be spinning (or im having a brain fart and need to think about it some more).

[Matt_]

Make sure you keep an eye on the driveshaft. If the drive shaft isn't rotating, and the passenger side isn't rotating when you rotate the driver side tire, i'd replace the actuator and go from there.

 

If there was a bigger problem than that with the front diff, it'd be making a hell of a lot of noise when you drive

[bhazely]

I explained it in my last post. It's simple, either the axle is engaged or its not (see that thread i linked previously for a breakdown of the internals and how the axle is actuated)

 

Was the drive shaft spinning at all??

 

Somethings not adding up. If you spin the passenger side tire, and the drivers side spins the opposite direction, but then you spin the drivers side, and the passenger side doesn't spin, then the driveshaft must be spinning (or im having a brain fart and need to think about it some more).

 

The drive shaft was spinning regardless of which tire I spun. The passenger side tire being spun moves the drivers side tire, when the tire is completely up, but when I put resistance on it, it doesn't spin. The driver's side tire doesn't spin the passenger side tire at all. I looked at the link that you sent, that is why I was wondering about the shifting mechanism for the transfer case. Sorry for the frustration on your end I haven't dealt with powertrain issues before. Thanks again for your help.

[Matt_]

Are you putting the truck in Auto-4x4 or 4x4?

 

If the t-case is engaged in 4x4, the driveshaft shouldn't be spinning.