NEED HELP No Front Axle Engagement After New Front Axle Disconnect And Actuator

[Fastlane]

Hello All,

I installed a new Front Axle Disconnect Assembly yesterday, and today, the first time testing it, the front axle won't engage in 4HI or 4LO. But it works like it should in A4WD, when the rear axle slips. I have tried much troubleshooting, and will do some more soon. I will try the steps listed here once again "http://gmtnation.com/forums/threads/4wd-not-working-step-inside.106/".

Can anyone point me in the right direction? I hear both noises from underneath. So I'm thinking it is going to lead to the transfer case. Like I said, I will try the troubleshooting steps again soon. I've searched many many forums and posts for a relatable issue, but can't seem to find a definitive answer...

The 4WD indicator lights function properly. No CEL, no service 4WD light.

Any help is appreciated.

Thanks,
Nick

Vehicle:
2005 GMC Envoy
All Stock

 

[Mooseman]

So if you put it to 4hi and try to turn on dry asphalt, does it crow hop? Would be strange that it works in A4WD and not in 4hi because all A4WD does is engage 4hi temporarily during slippage.

Have you changed the transfer case fluid?

 

[Fastlane]

So if you put it to 4hi and try to turn on dry asphalt, does it crow hop? Would be strange that it works in A4WD and not in 4hi because all A4WD does is engage 4hi temporarily during slippage.

Have you changed the transfer case fluid?

Thanks for the response!

I tested the system on my snowy incline driveway today, as we recently got 4 feet of snow. I had a helper watch the front tires, and in 4HI, there was no spin. In A4WD, there was spin after it sensed slippage in the rear.

I have not replaced the TC fluid yet, but is on my list to do.

I can't remember when 4HI or 4Lo has ever worked correctly, or decent for that matter.

Thanks again!

 

[Mooseman]

The TC will suffer if the fluid is not changed religiously at 50k. I'd do that ASAP.

 

[Fastlane]

The TC will suffer if the fluid is not changed religiously at 50k. I'd do that ASAP.

I plan to. It's been done before, don't exactly remember when.

Besided the fluid change, is there anything else you can point me towards?

Thanks!

 

[Sparky]

We can rule out the actuator since 1) you already replaced it and 2) it does engage since the wheels do spin.

That leaves only two or three things that I can think of, either the encoder motor isn't going into 4HI when commanded, the switch isn't actually commanding it to, or the case has an internal problem (caused by fluid or some other mechanical problem).

I'm tempted to say it isn't a mechanical issue with the case because it does throw power to the front wheels when commanded to in A4WD and the rears slip. The encoder is doing something because it does change modes there as well, but maybe it isn't fully changing. I don't remember if when in A4WD and a slip is detected if the encoder then turns to 4WD until the slip is gone or if that is controlled by something internal to the transfer case.

 

[linneje]

This problem has been brought up on this and the old site before. It is a problem with the encoder motor if it works is A4WD and not 4HI. Replace the encoder motor.