2000 4WD AWD engage grind sound

[shivsey]

Hello,

I recently just purchased a 2000 LTD 3.4L with rear diff locker and I have come across an alarming issue. When I shift into 4WD or AWD while going +30km/h there is a grinding/screeching sound for ~1 second while it engages the front diff. It has always manged to shift into 4WD within a couple seconds after the shift. I just changed all the fluids in the front/rear/transfer case with synthetic but that doesn't seem to be the problem. I have also greased the driveline zerk fittings. The only way I have found to get a nice proper shift is to be going at low speeds, ~20km/h. Unfortunately I havent had the time to go offroading and all the shift tests I have done have been on paved ground. The person I purchased it from claimed that the sound was always there since he got it ~5 years ago. Are there any suggestions of what to do to narrow down the problem and the part(s) that I might have to swap out?

I have tried searching for the past couple days but I cannot seem to find a thread referencing this issue.
Thanks.

 

[jgue467]

Just to be sure, you're not engaging the rear locker while on asphalt/concrete, right?

But like the old doctor joke goes, don't do it if it hurts (in this case don't do it above 30kms if you know it handles it well below 20).

How do you engage? Meaning do you let off the throttle when you press the 4WD button? Then wait for the 4 lights to go Green before applying throttle again? :smokin:

 

[shivsey]

Correct, I am not engaging the locking rear differential.

To engage the AWD I make sure I'm going straight, let off the gas for a couple seconds, click the J Shifter side button, wait for the green lights to go solid and the yellow centre to stop blinking then resume speed. Same goes for 4WD, but obviously by shifting the J shifter.

The slower I go the less grinding/screech I can hear and if I slow enough all I can hear is a very slight clunk.

 

[shivsey]

I think the fact that the grinding happens when both the AWD and 4WD help me further diagnose the issue. I can rule out anything to do with the centre differential. Does the push button send a signal to the transfer case actuator and the J-Shift do another thing or are they both the same in that matter?