4WD - proper engagement or inop?

ahimon

Original poster
Member
Jan 25, 2012
45
Here's what happened. I was on a boat ramp covered in snow (hard packed). The truck was in AWD and wouldn't move up the ramp. My right front wheel started slipping and spinning fast while the truck just sat still. I then put the truck into 4Wheel Low (while in Neutral) and I felt it engage. Then tried again to go up the ramp and got the same result (only the front right wheel spun fast) and the truck didn't move. No other wheels attempted to power the truck forward. Any ideas? Oh, one other thing..probably a coincidence.... I am getting a moaning from the right front at speeds above 30 mph. I'm thinking it's a wheel bearing.
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
I would guess the splined disconnect if it was the left front that spun, but that can't be your problem. I'm thinking more of the transfer case having a problem.

How many miles do you have, and have you changed the fluid every 50K as required? If you filled out your profile we wouldn't have to ask what year.

Also, don't use A4WD mode ever. If it's slippery enough to need 4WD, just use 4HI.

Do you have the G80 locker? Look on the glove box sticker. If you did, that would reduce the amount of rear wheel spinning, in case you also had some of that and didn't notice.
 

ahimon

Original poster
Member
Jan 25, 2012
45
04 Envoy XUV with the 5.3V8 and 180,000 miles. The fluid was changed less than 20,000 miles ago and I do a lot of highway driving. I looked in the glove box and can't tell if it has a G80 Locker? The RIGHT FRONT wheel was spinning and the rear wheels didn't move at all. Someone was on the outside of the truck watching what was going on.

Could it be that even though I heard the engagement putting it into 4WD I still needed to move the truck backwards a bit to get it to fully lock in?
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
In the glove box is a sticker with a hundred or so 3-character codes that detail all the build options. Do you see that sticker?

Moving a foot forwards or backwards or a slight turn of the steering wheel can help the splined disconnect engage, but that would only be the case if the right front wheel doesn't spin, and the other ones do.

If you're on dry pavement in a parking lot, can you go into 4HI or 4LO and drive slowly and turn the wheel and feel the engine bog down and the vehicle driveline bind-up as if the brakes are being applied?
 

ahimon

Original poster
Member
Jan 25, 2012
45
Yes, I see the sticker but don't see G80. Yes, the 4WD engages on dry pavement. I'm guessing it didn't lock in on the boat ramp for some reason. Just don't know why. I do think I have a bad hub bearing on that right front wheel and will be replacing that this weekend and see where it goes from there. I just didn't understand why only the right front wheel would spin and all other wheels stayed still on the ramp while in AWD and 4WDHI and 4WDLO.
 

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