96 4wd troubleshooting, Step 4 completed

[PopRichie77]

Did you have the engine running and the trans in neutral, if not the TC gears may not have been aligned, making it hard to shift. Be sure the parking brake is on and block the wheels or have someone hold the brake on. Do the shift quickly if you can, as the trans output shaft will be trying to turning the TC input, if you do it slowly it may grind, as it will turn in the neutral position. It shouldn't be that hard as there is a manual adapter that has a hand knob on it for shifting the TC manually.

 

[myf16]

Did you have the engine running and the trans in neutral, if not the TC gears may not have been aligned, making it hard to shift. Be sure the parking brake is on and block the wheels or have someone hold the brake on. Do the shift quickly if you can, as the trans output shaft will be trying to turning the TC input, if you do it slowly it may grind, as it will turn in the neutral position. It shouldn't be that hard as there is a manual adapter that has a hand knob on it for shifting the TC manually.

No, the engine was not running. If there's a manual knob, that means that spring-loaded return to H is not normal. But it might be normal for an engine that's not running and a certain position of the gears, I hope. I'll try your method in the morning. Thanks!

 

[myf16]

I tried with the engine running in Park and the t-case shifts by hand as smooth as butter! I'm going to try installing the new motor next.

 

[PopRichie77]

It's not my method, that's the way you are supposed to do it, when you turn the dash control, it is to be in neutral with the engine running, not park as the trans output shaft can't turn in park. You were lucky that the T case gears were aligned.
Hope the new motor fixes the problem.

 

[myf16]

PopRichie77, I might have done that in neutral and mis-stated it. Anyway I won't get the new motor on until Sunday. I had the ball joints checked and the lowers are being replaced today. That job is beyond my abilities and tools.

 

[Besty]

Hi guys I'm still trying to work out why my 4x4 won't engage. As stated in the thread I have done the following test.
1. Jacked the front end and the drive shaft turns by hand. In auto setting
2. Engaged 4x4, makes a clunk sound, leave the truck going and the drive shaft still turns by hand.
3. Turn the wheels and one goes in one direction and the other goes in the opposite. This is in 4x4 and auto.

What next guys? It a 1996xlt

cheers

 

[myf16]

Replacing the motor solved my problem of no 4low. It makes a reassuring clunk when switching to 4low.

I saw some rust on the old motor's bolts connecting it to the metal mounting bracket. I figured I'd rather spend the $80 on a new motor than spend time on an old one which was likely not worn out. I'm still happy with that decision.

Hi guys I'm still trying to work out why my 4x4 won't engage. As stated in the thread I have done the following test.
1. Jacked the front end and the drive shaft turns by hand. In auto setting
2. Engaged 4x4, makes a clunk sound, leave the truck going and the drive shaft still turns by hand.
3. Turn the wheels and one goes in one direction and the other goes in the opposite. This is in 4x4 and auto.

What next guys? It a 1996xlt

cheers

Betsy, your front axle is switching correctly and the transfer case motor is making the right noise. Maybe something broke inside the transfer case allowing the front driveshaft to turn freely with the rear wheels stationary.

 

[Besty]

Thanks myf16 for helping me out! I have replaced the transfer case a few days ago hence why I have posted my problem. I was thinking replacing the transfer case would fix the problem but no still the same result still no 4x4. I'm from Australia and live remote so have no other option than to try fix it myself!

 

[myf16]

Betsy, my limited understanding is that the front driveshaft is connected all the time through the chain, as in the picture at http://en.wikipedia.org/wiki/Transfer_case (front shaft on the right of the picture, transmission and rear shaft on the left). With this setup, when the rear shaft is frozen (by putting the rear wheels on the ground), so is the front shaft, unless the chain is broken.

 

[Besty]

So myf16, your saying the front chain is broken?
Besty

 

[PopRichie77]

Besty,
Read this, it describes the operation of the 4405 and shows the parts.
http://www.explorerforum.com/forums/showthread.php?t=182071

 

[myf16]

Besty,
Read this, it describes the operation of the 4405 and shows the parts.
http://www.explorerforum.com/forums/showthread.php?t=182071

Thanks for pointing me back there. I had skipped over the theory part of it when I was debugging my truck.

So myf16, your saying the front chain is broken?
Besty

Based on the following (underlining added), it appears that your GEM is not commanding engagement of the front driveshaft. GEMs are cheap on eBay if it's not some sensor.

Shifting to 4WD is done electronically by energiizing the electromagnet, which in turn actuates a very interesting electromechanical ball ramp clutch assembly. (More on this later)

The electromechanical ball ramp clutch assembly drives the drive sprocket after the generic electronic module (GEM) activates the clutch coil. The drive sprocket turns the chain which rotates the front output shaft and front driveshaft. In other words the input shaft and output shaft are locked, and the eledctromagnet actuates the gearing (through a clutch) that adds the sprocket attached to the chain drive, which then adds the front output shaft to the equation.

Can someone post what the GEM needs to sense before it engages 4WD? Dashboard switch position obviously, perhaps Neutral position on the transmission, perhaps brake pedal depressed. Anything else?