4WD Differential Lock Question

[amb]

Hello all,

I've been looking for some help with a problem I had in this crazy snow in Chicago. I own a 99 Yukon Denali, tried to get it out of the garage in a couple feet of snow. For the first time ever, the truck got stuck...just getting out of the garage!

Here's what was happening...when in 4LO or 4HI only 2 wheels (one from each differential) was spinning, seemingly the ones with the least resistance, and the truck wasn't moving.

I had to put some pressure on the brake, and lightly tap the gas for the wheels to lock. This resulted in an intermittent pulsing of the locking, but you could tell the wheels were actually locking for a split second at a time.

Eventually the wheels locked, and started spinning together, at this point the wheels were still spinning on the snow/ice. It took awhile, but finally got it out of the snow and back in the garage.

I figured the locking mechanism is not working properly.

At first it got me worried something is wrong, then a plow came by with a Dodge pickup, and the it did the exact same thing. So now i'm confused.

Were my wheels locked and this is normal operation?
Were they not fully locked....maybe some snow got in the solenoid mechanism...then I finally got it to lock and started worked properly?
OR is the locking mechanism somehow malfunctioning?

I'd appreciate any help...thanks in advance!

amb.

 

[SunlitComet]

If a differential locker was installed then only the rear axle should lock when required. The front diffferential does not have one. If it did it would probably blow up the differential case. What wheels eventually locked front or rear or both?

 

[96ProCompTahoe]

sounds like you have an open diff in the rear (no G80 option) and the front doesn't have a locker option from the factory. normal. when one wheel slips front of rear it will spin, no locker= nothing to transfer the power to the wheel thats not spinning.

if you have the G80 code in the glovebox, you may want to get the factory locker looked at since it is obviously not working properly.

 

[amb]

Thanks for the feedback.

I'll take a look at the diff code in a few minutes.

I was under the impression that when in 4hi or 4lo, that all four wheels should be turning together all the time, am I wrong?

 

[BlkYukon95]

Nope, just two. The rear will be a limited slip if you have the G80, otherwise the wheel with the least resistance will be spinning.

 

[destroyer1362]

Yeah I got a g80 in mine, it locks when it feels like it. Sometimes it locks up like it should other times it has to roll a few inches forward with one wheel spinning before it locks.

 

[07Burb]

Nope, just two. The rear will be a limited slip if you have the G80, otherwise the wheel with the least resistance will be spinning.

x2

 

[99Yuk]

..I was under the impression that when in 4hi or 4lo, that all four wheels should be turning together all the time, am I wrong?

Not if you run a Jeep TJ Rubicon!
Otherwise, just two, possibly three.
One up front for sure, and one or two in rear, depending if you have the G80.

 

[kenbarls]

4WD and differential locks should be used to prevent getting stuck - they might not work to get you out of stuck situations.

 

[justinp95]

Are the OBS denali's not awd then?

 

[07Burb]

Are the OBS denali's not awd then?

Nope...4WD...I think the Denali's started being AWD in '02 or so but I could be slightly off on that stat but I'm sure someone will correct me. But I know for sure the '99 and '00 Denalis were 4WD

 

[LodestarProServe]

Interesting thread but it died too soon
I'd like to install lockers in the rear of my 99 Tahoe. I'm no stranger to a wrench but a couple quick questions...
1. How difficult will it be to install RDiff lockers?
2. Shouldn't "AWD" mean auto-locking? I know it's "old" tech, but it's my understanding that you have either 4wd (two wheels spin, then the diff locks up in the rear) or you have AWD which - SHOULD - mean all wheels drive.

Or did I just open a huge, messy can of worms?