A4WD in snow sucks - CRASH!

[LordBear]

awakening an old thread..hahahaha

i kinda played with the a4wd a little bit. to see exactly what i did and not sure if i got it to do anything or not down in the sand. but in any case.... if i am worried about slick roads snow ice or what ever... i would rather just put it in 4 to start with.. so you already have the traction in place instead of having to be in a situation where your spinning your tires before the system kicks in. where you have 2 issues the one that caused the ops adventure but also seems hard on your system and being uneeded stress on our system.. im no specialist on the subject..but i would rather play it safe. in 4 i seem to do just fine in the car and grips and works well from my experiance. how ever.... cant believe how much it binds up while turning... that does worry me.. some times tighter turns are needed.

 

[Playsinsnow]

Are you driving in 4wd on on dry pavement? Don't!


That binding is because the inside wheel on the turn has to do something to keep up with how much the outside wheel has traveled. Think turning radius for each front tire. If you went hard enough it will do a crow hop. This is normal. Don't use A4WD and don't whip doughnut s in 4wd and keep your 4x4 speed under 40mph. Unless you want to replace your disconnect. I beat the heck out of mine and changed my habits because of it. Sure was fun though.


You're exactly right about it connecting with crappy factory grease at any speed. It will and does break or wear down.
I switch into 4 at a standstill now. I won't mention the things I did to it in 4wd on snow haha

 

[strat81]

I've been happy with the AWD on my Rainier (equivalent to being in A4WD all the time on the TBs and Envoys). It works as advertised in inclement weather and relatively deep snow. Switching from all-seasons to winter tires has made a noticeable difference in how frequently the AWD engages. That is, with winter tires and the G80, it's usually just the rear doing the work. It's gotten me through unplowed 12" snow and hard-packed 2" snow.

Slow down and drive appropriately for the conditions, regardless of whether you have 2WD, 4WD, or AWD.

 

[MichEnvoyGuy]

I've been happy with the AWD on my Rainier (equivalent to being in A4WD all the time on the TBs and Envoys). It works as advertised in inclement weather and relatively deep snow. Switching from all-seasons to winter tires has made a noticeable difference in how frequently the AWD engages. That is, with winter tires and the G80, it's usually just the rear doing the work. It's gotten me through unplowed 12" snow and hard-packed 2" snow.

Slow down and drive appropriately for the conditions, regardless of whether you have 2WD, 4WD, or AWD.

After years of having a selectable 4wd and never using the Auto4wd option, and having just gone to AWD that acts like its always in a4wd, right before a Michigan winter, LOL, I think its gonna be an interesting winter for me....

 

[strat81]

After years of having a selectable 4wd and never using the Auto4wd option, and having just gone to AWD that acts like its always in a4wd, right before a Michigan winter, LOL, I think its gonna be an interesting winter for me....

Exercise your transfer case and be sure to change the fluid unless you know for sure it was recently changed.

We have plenty of gravel roads around here that I can test the AWD and ABS on. You'll feel a slight lurch or bump as the front wheels engage.

 

[Playsinsnow]

Slow down and drive appropriately for the conditions, regardless of whether you have 2WD, 4WD, or AWD.

 

[CaptainXL]

I've been happy with the AWD on my Rainier (equivalent to being in A4WD all the time on the TBs and Envoys).

Nope, not equivalent. AWD vehicles have a three separate differentials that allows the front and rear driveshaft's to spin a different speeds. Part time 4WD vehicles only have two differentials.

 

[HARDTRAILZ]

Nope, not equivalent. AWD vehicles have a three separate differentials that allows the front and rear driveshaft's to spin a different speeds. Part time 4WD vehicles only have two differentials.

Where are these 3 differentials?


FYI---the driveshafts do not spin at different speeds.

 

[MichEnvoyGuy]

Nope, not equivalent. AWD vehicles have a three separate differentials that allows the front and rear driveshaft's to spin a different speeds. Part time 4WD vehicles only have two differentials.

Interesting... I, too, thought it was like being in A4wd all the time.

 

[HARDTRAILZ]

Interesting... I, too, thought it was like being in A4wd all the time.

It is. He once again does not know what he is talking about.

There is a front and rear diff that send power to the axles and there is a transfer case which splits power front and rear. There is no third diff. There are clutches in the transfer case that direct the amount of power to the front and that can be an issue if not properly serviced.

The driveshafts spin the same speed or it would destroy the transfer case when it engages.




Here is another member's explanation if it makes more sense to you this way....
"To be honest, the Buick and olds trucks don't have a true AWD transfer case.
A "real" AWD system uses a continually engaged transfer case with the ability to adjust (read vary) the power being sent to the front differential. When the rear wheels are under a low traction situation, only required power is sent to the front. In other words, power sent to the front can vary from 0% through to 50%.
The Buick/Olds trucks have a 4x4 transfer case with some of the parts removed. These cases have an internal clutch pac and when the front wheels need power, the clutches operate. These cases can not vary the power, only provide 0 power (no slip) or full power (which is 50% because the other 50% goes to rear wheels).
Hope this helps"

 

[Playsinsnow]

Know the system is all. Even awd models varied. A fav of mine, wrx has an open front diff, vicious lsd center, and a lsd rear. Again this changes from model trim/years to manufacturers. The Evo is another fav. True AWD systems. Do the research before you build someone's confidence and crASh!

Edit:
An awd model vs 2wd model will be heavier with the extra parts and one would think with the extra weight, it has to add to the stopping distance....

 

[strat81]

Nope, not equivalent. AWD vehicles have a three separate differentials that allows the front and rear driveshaft's to spin a different speeds. Part time 4WD vehicles only have two differentials.

I believe you are mistaken. Point me to a part number for a Rainier center differential, here's a link to a schematic of the internal parts of the NP126 transfer case: TRANSFER CASE (NP4) PART 2 INTERNAL COMPONENTS (NVG 126C). Fits: BRAVADA 4WD, ENVOY 4WD, ENVOY 4WD DENALI, ENVOY 4WD SLE, ENVOY 4WD SLT, ENVOY 4WD XL, ENVOY 4WD XL DENALI, ENVOY 4WD XL SLE... | Nalley Buick GMC Brunswick.

The AWD system in the Rainier and Bravada is a neutered version of the 4WD system found in the Trailblazer. The system is not full-time AWD (such as the fancy systems on Audis, Subarus, etc.). The system is RWD until slip is detected, at which point the AWD system engages. The Rainier and Bravada do not have a center differential. This is readily apparent when going from a low-traction surface such as snow or gravel to dry pavement when the wheels are turned as driveline binding is experienced. Rainiers also have encoder motors to shift from RWD to AWD, just like Trailblazers do.

The Buick Rainier AWD is a dumbed-down, neutered 4WD system off the Trailblazer. The most notable difference between the two systems (besides the lack of control) is the missing low-range in the Rainier.

 

[strat81]

Know the system is all. Even awd models varied. A fav of mine, wrx has an open front diff, vicious lsd center, and a lsd rear. Again this changes from model trim/years to manufacturers. The Evo is another fav. True AWD systems. Do the research before you build someone's confidence and crASh!

Edit:
An awd model vs 2wd model will be heavier with the extra parts and one would think with the extra weight, it has to add to the stopping distance....

And then there are systems such as the Toyota Sequoia which offers a locking center differential.

The labels AWD and 4WD tell us very little about how many wheels are driven, how they are driven, when they are driven, or what level of control the driver has over the system. Part time, full time, locking, limited slip, low range, viscous couplings, clutch packs, chain driven... there are plenty of ways to get power to the ground.

For those scratching their heads about center differentials:
Welcome to Land Cruiser Owners On Line

 

[Decado]

I'm glad this thread was resurrected. I have learned that I did not know as much as I thought, and I am now going to do some extra research on AWD systems; specifically the setup in my Envoy.

Thanks for making me feel dumb!

 

[Playsinsnow]

Hopefully you feel smarter now! Toyota definitely has some cool options when it comes to alltime 4wd, I am more familar with the 4runner.

Question for all, Best domestic AWD platform/system? We have to have something

 

[smokey262]

So a couple questions from a new guy;

Why is it not advisable to drive over 40 mph when in 4wd?

What is it about the power steering pump that causes it to self destruct when doing donuts in snow or sand?

Is there any scenario where A4WD is OK to use?

 

[Playsinsnow]

4wd should not be used on dry pavement, so maintaining highway speeds puts unnecessary strain on drivetrain. I drove 200+ miles doing 50+mph through WY in 4wd. Then my disconnect went out. For that reason and others.

Whipping donuts creates a strain because of the way some go from lock to lock with the steering wheel. I whip a few every snowfall for 6years now and the pump whines and works like always. Until it gets annoying or fails is when it will get replaced. I won't stop intentionally fishtailing it

The A4WD has a metal fork that slips a gear onto another. At any speed this connection has to slam two gears together. Faster you go, the harder it is on the disconnect. Again ask me how I know lol. Use 4wd when necessary or drive slower in 2wd. Roadie can explain this very well, as he has done so many times! searching for some old threads now for you. And the packers suck



Whip doughnuts in 2wd not 4!


Edit: I never use A4WD anymore and advise all others to do the same. You can trust the owners manual for guidance or here from people who had to repair this intuitively designed GM part.

 

[gmcman]

I missed this thread the first time around, but hey, winter is coming so why not bring it back.

ED, I think the reason you crashed is not solely from the A4WD, but hitting the turn too hot. Once you broke traction there was no regaining it until the tires slowed down..or you slowed down on your centrifugal trajectory...

I have the wifey use A4WD when she's in a parking lot when there's snow on the ground, if I haven't changed the tires over yet......cough, Blizzaks, cough, barely ever need 4WD...cough.

I learned the hard way just like you with my front-wheel drive car in the snow. Coasting through the turn is fine, break the tires loose it just plows to the outside.

 

[strat81]

So a couple questions from a new guy;

Why is it not advisable to drive over 40 mph when in 4wd?

What is it about the power steering pump that causes it to self destruct when doing donuts in snow or sand?

Is there any scenario where A4WD is OK to use?

Use A4WD when there is 4+ inches of snow on the ground. For most uses, 4HI and 4LO should be used only if you're stuck or if you're following the roadie off-road. IMO, if you're driving in conditions that are so bad that you NEED power to the front wheels ALL the time, you probably shouldn't be out driving in such conditions.

If you can't handle 2 inches of snow in 2WD/RWD, you shouldn't own a car.

 

[Playsinsnow]

Disregarding tires I have to respectfully disagree with the use of A4WD in 4+ inches. The front connects AFTER the rears slip. AFTER. Meaning you have already lost traction. Use of 4wd with low speeds will keep the traction planted as well as you can in slippery conditions as best as possible.

Edit: use 4wd or stay in 2 and learn to slide the beast! Feather that throttle

 

[smokey262]

My usual practice when using 4WD in snow is to put it in 4HI and call it good until I get back to dry pavement. Snowy conditions usually (but not always) mean going 45MPH or less, and the snow allows allows differential wheel speed on turns without binding. I presume that these are not going to break my new toy, yes?

So I understand the part about putting it into 4WD stopped and in neutral, but how about shifting back to 2WD? Can this be done while moving slowly forward or even at speed?

 

[Playsinsnow]

So I understand the part about putting it into 4WD stopped and in neutral, but how about shifting back to 2WD? Can this be done while moving slowly forward or even at speed?

One would think getting it out of 4wd is easier than going in, but the lower the speed the better for both. I do complete stops now to baby it.

For the record I spent 2.5 long winters shifting on the fly @50-60mph no problem. Notice how I said 2POINT FIVE! Yep she went... gears inside disconnect were rounded and shaved.

 

[CaptainXL]

I believe you are mistaken. Point me to a part number for a Rainier center differential, here's a link to a schematic of the internal parts of the NP126 transfer case:.

My bad. I was thinking of full time transfer cases. Not ours. I thought it also applied to the TBSS?

 

[HARDTRAILZ]

I never use a4wd. I either need 4x4 or I don't.

 

[CaptainXL]

I never use a4wd. I either need 4x4 or I don't.

Same here. A4WD has been proven (here and on the OS) to be unsafe when whipping around corners in the snow and ice. Not that I drive like Andretti in the snow and ice.

 

[Playsinsnow]

The first winter I had the tb I let the wife take it to get groceries (she timed me well, I just got home from boarding in a snowfall) She got hung up on the concrete apron a foot outside garage door pulling in. Puts it in A4WD and goes. Rear slips and she put the rear pass side panel into the garage trim.

From then on it never saw A4WD. When my disconnect went, I joined the OS and since have learned so much!

 

[HARDTRAILZ]

My bad. I was thinking of full time transfer cases. Not ours. I thought it also applied to the TBSS?

Thought which part applied to the SS?

Full time TC still do not let the driveshafts spin at different speeds.

 

[AtlWrk]

Whipping around corners in the snow and ice has been proven (here and on the OS) to be unsafe.

^Fixed it for ya ^

For what it's worth I find the A4WD extremely useful in the winters here in CT. Road conditions change from street to street.

Case in point: turning sharp off a wet but salted main road onto a snow covered hill on my way to work. It's unavoidable and is the case for much of the winter. If I'm in 4WD before I get to the turn I will bind and crow-hop hard. If I'm in 2WD I will lose traction the second my rear wheels get onto the steep snowy hill. However, if I'm in A4WD I can make the turn without stressing the drivetrain and, knowing that i'll need it, I can goose it just a little to engage the front wheels and make it up the hill no problem--MUCH faster and smoother than trying to switch over mid-turn.

IMHO it's all about knowing the system well enough to anticipate when it's going to kick in, being ready for it and using it to your advantage.

 

[strat81]

whipping around corners in the snow and ice.

That's how people crash into brick mailboxes.

It's funny... I see far more 4x4 vehicles in the ditch when it snows than 2WD. I see it out here in NE and I saw it back on the east coast when I lived in NY. I doubt it's the vehicles' fault - it's just a machine. I suspect it has to do with overconfidence of the driver. Many do not realize that 4WD does not give you more traction, nor does it help when trying to slow down.

 

[strat81]

Disregarding tires I have to respectfully disagree with the use of A4WD in 4+ inches. The front connects AFTER the rears slip. AFTER. Meaning you have already lost traction. Use of 4wd with low speeds will keep the traction planted as well as you can in slippery conditions as best as possible.

Edit: use 4wd or stay in 2 and learn to slide the beast! Feather that throttle

The rear wheels can lose traction independently of the front wheels. Just because the rears have lost traction doesn't mean the fronts have. Additionally, slip indicates a variance in wheel speeds, not necessarily a complete loss of traction.

In my experience with AWD and A4WD in GMT360s, those modes are beneficial for typical city driving in snow. At a red light or stop sign, they can help keep the vehicle straight when accelerating from a stop. Inexperienced drivers tend to go heavy on the throttle and get the vehicles sideways while taking off in 2WD, especially with an open diff rear or a lazy G80 or limited slip. Rather than playing with the transfer case buttons for 2WD and 4WD every time you come to a stop, A4WD lets you "set it and forget it".

Atlwrk above illustrates another good point: varying road surfaces. I encounter that here where we have main arteries, side streets, and country roads that see varying levels of road clearing when it snows.


The two best things I have found for getting around safely in the snow? Slow down, and get winter tires. Winter tires give you the added benefit of helping you stop in addition to accelerating.

 

[KrisE]

That's how people crash into brick mailboxes.

It's funny... I see far more 4x4 vehicles in the ditch when it snows than 2WD. I see it out here in NE and I saw it back on the east coast when I lived in NY. I doubt it's the vehicles' fault - it's just a machine. I suspect it has to do with overconfidence of the driver. Many do not realize that 4WD does not give you more traction, nor does it help when trying to slow down.

Isn't that the truth! Even with 4WD and great tires on my Yukon I got nervous with those people who drive 60 on fresh blizzard snow whizzing by me.

When I bought this car last week, they'd put some odd korean? tires on it. I'm going to try them out but doubt they'll suffice in our MN winters. I've always done high-end radials and been fine. Going to try winter tires and swap out since I have these and they do pretty well in summer.

I have been reading about winter tires and I didn't realize that they're good for 3-4 years then the tread isn't effective anymore. That really equates to all season tires going out in 2 years (30K miles). Yet, Blizzak's will run around 600 installed. Still contemplating just putting on some good 60K all-season radial's on them that are rated well for winter and dumping these summer tires.

 

[strat81]

Isn't that the truth! Even with 4WD and great tires on my Yukon I got nervous with those people who drive 60 on fresh blizzard snow whizzing by me.

When I bought this car last week, they'd put some odd korean? tires on it. I'm going to try them out but doubt they'll suffice in our MN winters. I've always done high-end radials and been fine. Going to try winter tires and swap out since I have these and they do pretty well in summer.

I have been reading about winter tires and I didn't realize that they're good for 3-4 years then the tread isn't effective anymore. That really equates to all season tires going out in 2 years (30K miles). Yet, Blizzak's will run around 600 installed. Still contemplating just putting on some good 60K all-season radial's on them that are rated well for winter and dumping these summer tires.

I used to be very skeptical about winter tires. I finally took a gamble and tried some, and now I'm a True Believer.

I ended up getting refurbished factory wheels for my Rainier off eBay for only about $10 more than steel wheels would have ran me. If you have an I6 SWB, you won't need 17" wheels like I did. Between shipping and taxes, a full set of winter tires and wheels ran me about $1,000. I went with Firestone Winterfires which are admittedly a low-end winter tire, but the difference between them and all-seasons was astounding and I'd certainly consider buying them again. I can't imagine how good premium winter tires such as Blizzaks or Nokians would be.

TireRack.com has several articles that outline instrumented testing that has been done comparing all-seasons versus winter tires.

 

[C-ya]

For what it's worth I find the A4WD extremely useful in the winters here in CT. Road conditions change from street to street.

Case in point: turning sharp off a wet but salted main road onto a snow covered hill on my way to work. It's unavoidable and is the case for much of the winter. If I'm in 4WD before I get to the turn I will bind and crow-hop hard. If I'm in 2WD I will lose traction the second my rear wheels get onto the steep snowy hill. However, if I'm in A4WD I can make the turn without stressing the drivetrain and, knowing that i'll need it, I can goose it just a little to engage the front wheels and make it up the hill no problem--MUCH faster and smoother than trying to switch over mid-turn.

IMHO it's all about knowing the system well enough to anticipate when it's going to kick in, being ready for it and using it to your advantage.

^^^^

This is how I utilize the system. I understand it's limitations and have seen it's benefits. These things are balanced weird to drive in 2WD in the snow. I drove a 2WD pickup for 7 years here in MI, so I know a little about driving a 2WD vehicle in the snow. I added 250# of sand bags behind the wheel well and again, understood my limits. The first time I tried to take off from a stop sign in the snow in the TB, I was fishtailing everywhere. Granted, it can be fun, but it is not always safe to do so. I tried several times to come off the line straight or with minimal fishtailing. Doesn't seem possible. I can feel the G80 lock up and both tires spin, but it is a different feel than the ole one legged dog in my GMC p/u. After a couple of times trying to stay straight, I put it in A4WD and eased off the stop. Once the rear slips and the G80 locks, I could feel the front grab and straighten the truck right back up. Since I know it a shock to the system, I ease onto the gas to introduce as little stress into the system as possible. If it is particularly nasty out, I'll switch to 4HI and leave it there until conditions warrant a drop back to A4WD or 2WD.

This winter I'll try adding weight in the back to see if that helps the balance and/or traction and see if I can use 4WD less often.

 

[The_Roadie]

A collection of replies:

It's funny... I see far more 4x4 vehicles in the ditch when it snows than 2WD.

Indeed. When I moved from New England to Oregon and saw hundreds of new refugees from the recession in California in 1993 all buying SUVs for the first time, it's like they ALL neglected to understand that even 2WD vehicles have 4-wheel brakes. Their braking performance was not enhanced. Numb nuts.

Case in point: turning sharp off a wet but salted main road onto a snow covered hill on my way to work.

The only time I ever advise using A4WD mode. Variable conditions.

When my disconnect went, I joined the OS and since have learned so much!

The OS like Trailvoy, or ORTB?

I never use a4wd. I either need 4x4 or I don't.

Precisely, comrade! Wussy or underinformed amateurs slap it into A4WD not knowing the systems. Like it's a "get out of shit free" card or something.

So I understand the part about putting it into 4WD stopped and in neutral, but how about shifting back to 2WD? Can this be done while moving slowly forward or even at speed?

I would have no qualms about doing that at slow speed. One can argue (if one knows what's really going on) that a disengagement of the disconnect is a low-energy event, and can be done at speed.

I have the wifey use A4WD when she's in a parking lot

EVERYBODY should practice using the A4WD mode in turns and accelerating in a parking lot, to get a feel for how the system really works. And then decide if they can handle the engagement surprise. And to confirm the system really works and you don't need maintenance.

Whipping donuts creates a strain because of the way some go from lock to lock with the steering wheel.

In my analysis, the issue is less of the turning, but entirely of the steering wheel being at lock. The pressure goes up at lock, the driver is keeping it in that state for an extended time, and THEN increases the pump RPM by leaning on the gas. The pump was designed to handle the pressure at low RPMs in parking lots, which is the only place you should be at full lock. Doing donuts at high RPM with an extended time in the lock state, shears the shaft between the pulley and the pump vanes. I consider it to be a teenage-driver-idiot-detection-system. Especially when we get posts about idiot kids doing that and want to know how to fix it before their parents find out. Or posts from parents with dead power steering and a kid pretending denial.

The A4WD has a metal fork that slips a gear onto another. At any speed this connection has to slam two gears together.

It's worse then you think. In 2WD mode, if the front driveshaft isn't turning, then the open front differential will be turning the intermediate shaft BACKWARDS by way of the spider gears due to the rotation of the driver's CV shaft. The passenger CV shaft is turning its side disconnect gear forwards. Engaging the disconnect while moving is asking the sliding collar to lock together two COUNTER-ROTATING gears.

Why is it not advisable to drive over 40 mph when in 4wd?

If you're on dry pavement, it's just dumb. If you're on slippery surfaces you might be going too fast for conditions. That said, I've used 4HI mode often on desert washes that might be 250 feet wide, I can see no traffic coming due to a lack of dust plumes for miles, the surface is washboardy and even with aired down tires it's better for the vehicle to ride along on top of the bumps instead of in them, and I'm feeling my oats and have the intermittent need for speed. So I've been known to float along at 60 MPH on washboards, as long as I know there's no 6-10" steps coming up because I've driven the trail the other way without a rainstorm in the interval since I've seen the trail. That reminds me, winter desert season is coming up, and there have been a LOT of flash floods that have changed the nature of every single trail out there this year. The first weekend I go, I usually have to survey everything there in a pre-run, to find the recent rockslides that might have closed or relocated the trail paths.

What is it about the power steering pump that causes it to self destruct when doing donuts in snow or sand?

Explained above.

Is there any scenario where A4WD is OK to use?

Yes, but it's rare, and you should use it with full understanding of how the system works and the damage you can do to the transfer case clutches by leaving it in when you really don't need it.

 

[AtlWrk]

It's worse then you think. In 2WD mode, if the front driveshaft isn't turning, then the open front differential will be turning the intermediate shaft BACKWARDS by way of the spider gears due to the rotation of the driver's CV shaft. The passenger CV shaft is turning its side disconnect gear forwards. Engaging the disconnect while moving is asking the sliding collar to lock together two COUNTER-ROTATING gears.

I remember my first kudos of sorts from you on the OS for coming to this realization:wootwoot:.

However, I later realized that (unless there are programming differences among the years) my transfer case encoder always engages the prop shaft before the disconnect actuator moves the collar. This means that the intermediate shaft is brought up to speed with the passenger CV shaft before engagement. Similarly, the disconnect pulls back before transfer case releases the prop shaft.

 

[The_Roadie]

However, I later realized that (unless there are programming differences among the years) my transfer case encoder always engages the prop shaft before the disconnect actuator moves the collar. This means that the intermediate shaft is brought up to speed with the passenger CV shaft before engagement. Similarly, the disconnect pulls back before transfer case releases the prop shaft.

Interesting observation, and that would be a good design. I can't explain why so many people who overuse A4WD mode have worn-out gears and collars, then.You saw that happening on a lift?

 

[TollKeeper]

Another suggestion for those of us that are about to deal with the white stuff...

The front diff actuator, for me, is a known problem of not liking to work when its cold. To make sure I have the 4x4/a4wd when its needed, I will put it into A4wd a couple days before, and when the engine is hot. This means that the oil/grease is also warm, and allows the actuator to move. Old grease getting cold, and hard is the culprit to this. As far as I know, it will stay engaged until I turn it back to 2wd. Maybe Roadie can confirm this?

 

[The_Roadie]

The front diff actuator, for me, is a known problem of not liking to work when its cold. To make sure I have the 4x4/a4wd when its needed, I will put it into A4wd a couple days before, and when the engine is hot. This means that the oil/grease is also warm, and allows the actuator to move. Old grease getting cold, and hard is the culprit to this. As far as I know, it will stay engaged until I turn it back to 2wd. Maybe Roadie can confirm this?

I'm still advising against running in A4WD mode at all unless the conditions in front of you require it. And that's rare. Allowing the engine to come up to temp will warm the oil, and thus warm the actuator that's bolted to it. The actuator will stay in place until you go back to 2HI, yes. It doesn't reset every time the ignition goes off.

Old, congealed grease should be a huge hint to rip out the actuator, rebuild it with proper all-temp synthetic grease like the article on ORTB illustrates, and not risk ruining the $500 unit. What you're doing can risk damage to the more expensive transfer case.

Or you might win the bet and neither one of the units will die on your watch. I tend to keep vehicles forever, and give them away to friends or relatives when they're totally not fitting my needs anymore, so that makes me think long term. Folks who might trade vehicles like they're a fashion statement have different priorities that often neglect deep maintenance risks. Not that most people here are like that, but I know a few.

 

[Jtyler77]

When I had my 06 Silverado I tried the A4wd on the highway with a slight incline it would bang in an out on the small snow difts at 50 mph. Scared the crap outa me. Also felt like it was destroying itself. Never used it again and don't plan to with the TB either. My friend complains of the same thing with his 04 Silverado.