NP 205 run Full time 4x4

[6.2Blazer]

People make WAY more of an issue of running a truck in 4wd on dry roads than it really is. I do automotive durability testing in my job for manufacturers and part of most of the testing is locking a truck into both 4 high and low for up to 50% of the time (10,000-20,000 miles) and running around on dry roads at both high speeds and doing slow speed lock-to-lock turns. I've seen very few failures that could directly be attributed to running in a 4 locked position on dry roads.

I've owned 4 different 4wd trucks with "part-time" systems and have always put them in 4wd and left it there if the roads were questionable or spotty with snow or ice. Two times I did this were 50+ mile trips in my 2500HD pulling a 9k trailer, and having it 4wd saved me several times from jack-knifing the trailer because I turned the front tires into the slide and powered out of it...no way you could have gotten out of trouble in 2wd.

Anyway, there is no reason why you can't leave the truck in 4 high if there is periodic patches of snow and ice on the roads. If you are cruising down a road at 55 mph you just can't go "oh look, some snow ahead so slip it into 4wd".......by the time you do this it's too late.

I think another thing is that most people are thinking of only using 4wd to not get stuck. I completely agree that on just icy or light snow roads you don't need 4wd to actually move, but it greatly helps handling and keeps the rear end from fish-tailing.

Just a couple weeks ago I took my dedicated trail rig for a quick spin down the road to check everything out and didn't realize until a couple miles that it was in 4 hi (kids were playing in it and had hit the shifter), even with a lockers front and rear. I did notice something slightly off, but with a welded rear diff and 10 psi in the 40" TSL's it always feels weird on the road.

 

[El Larry]

I have a 203 in my Blazer, and unknown to me when I got it, previous owner had it in 4High-Loc. I drove it this way for 4 months on pavement before figuring it out, it did however boil the tranny fluid out of the dipstick 3 times. Twice after towing my flatbottom. I'm a lucky schmuck though, all 3 times it was after returning home when it happened. I'm swapping to a manual as soon as possible, I don't like autos. The 203 still works fine though.

 

[moneypit_K5]

Around here there can be ice/snow and bare pavement on the roads. So it does not make sence to unlock the 4x4 on pavement when in a few miles I could be on snow.. a few miles later back on pavement.

BWHAHAHAHAHHAHA!!!!!!

You are in Washington, not Antartica. You don't need full time four wheel drive. Leave the hubs locked, and shift it into 4 High when you need 4 wheel drive.

Why not just trade that big old hard to control K5 in for a nice new subaru?
sounds like it might suit you better in our incredibly harsh winter conditions...

Wow. You're the opposite of what everyone else is doing. Where everyone else has a 203, they want to swap to a 205 to get away from the 203 which has a bad rep to it.

Ive got a few 203's, I'll trade you straight up for that 205.

 

[loafer]

There used to be a company that made a "bolt-in" viscous coupling unit (VCU) that you could bolt in between your drive shaft and the t-case. These only would work on cases that have a flanged front output though and you would need to shorten your driveshaft a little. The VCU is just a fluid coupling that allows some “give” to make up for the different speeds between the front and rear diffs.

You would have to do some searching to see if they’re still available. Maybe ebay?

 

[wazzabie]

Anyway, there is no reason why you can't leave the truck in 4 high if there is periodic patches of snow and ice on the roads. If you are cruising down a road at 55 mph you just can't go "oh look, some snow ahead so slip it into 4wd".......by the time you do this it's too late.

That is exactly the problem. I drive up in the Mt. passes on over to Eastern Washington. There is a lot of patches of ice, compact snow and dry pavement. I just can't change over into 4hi when I see this coming.

 

[jonathon]

You don't need 4wd at highway speeds.. it's not going to help you at all doing 55+, your driving ability is what counts when you hit a patch of ice. 4wd won't help you stop or steer.

The only times I use 4wd are when I'm doing a steep hill. Most people from the midwest don't understand that rwd + snow and ice + hills = all your gonna do is slip and slide.

 

[6.2Blazer]

You don't need 4wd at highway speeds.. it's not going to help you at all doing 55+, your driving ability is what counts when you hit a patch of ice. 4wd won't help you stop or steer.

I disagree. Sure, it won't help you stop but it does help you steer. But the biggest thing is it can keep the truck going straight to begin with. I've both been driving a truck and a passenger in a truck running in 2wd just cruising at a steady speed on a straight road when the rear tires let go and it starts to fishtail. Running in 4wd will help prevent this from happening.

I guess you do need to know how to drive the appropriate way to take full advantage of 4wd. Just look at all forms of automotive racing at it's almost always the case that the 4wd version of the race vehicles are faster.....why? Because they handle better and you can go around corners faster without spinning out. I know racing is different than daily driving, but the idea is the same.

 

[yellowK20]

You guys all need to go back to drivers ed. Blazers and Subbys are awesome in the snow and ice on pavement because of all the wait over the rear wheels . I cant wrap my head around how you guys feel the need to run Highway speeds in 4wheel drive. if the road is that bad you need to slow the **** down.

as for hitting a patch of ice .......... again it comes to be being in control and not going to fast for the conditons. People have forgotten how to drive in this country they really to heavily on antilock brakes ,all-wheeldrive,traction control ,etc

 

[yellowK20]

. I just can't change over into 4hi when I see this coming.

yes you can, all you have to do is take your foot off the gas and pull the lever into 4-hi if you already have the hubs locked in takes less than 2 seconds
you dont have to stop or pull overand the same goes for disengaing ( as long as its not bound up which it will be if you run it on hard dry surface for extended periods

 

[moneypit_K5]

once again yk20, ya hit the nail on the head.

 

[chulisohombre]

my 205 doesnt shift on the fly,and i have never wanted to jam it into 4 wheel when moving.it just seems like its too easy to break something that way.if you dont get it into gear all the way then you are grinding your gear half meshed and then you got more problems.in either case if you dont see the bad road ahead in time and you jam it into 4 wheel at some point you are going to have to slow down some to get it into gear correctly.so i still vote if conditions are bad enough,leave it locked in.maybe its just me but i dont want to spin out or break something trying to do something that could already be done.unless you have lockers steering will not be a problem and it will help pull hills with a lot less problems.

 

[yellowK20]

well my 76 K20 will go into gear as well as every other NP205 I've ever owned if the hubs are locked in and your coasting ( as in not on the gas) it will slide into 4-hi

I still say you guys are wack for "needing" 4x4 on level ground on pavement no matter how Icy. as long as when you hit ice your smooth on the accelarator its not gonna slide.

and if your already sliding 4x4 isn't gonna help you unless you get lucky and can accelarate out of your skid

 

[blazinzuk]

every 205 I have had will shift in and out of 4 hi when i let off the gas too. Would shift in and out all the time couple of times up around 65

I will tell you I loved my 203 in the wintertime though. It was great to not even have to think about it. Not really necessary on the highway but sure nice in town.

 

[Fordum]

Binding is not the right word for it. Try total lockup.
If you run on dry pavement with the 205 in 4wd and the hubs locked, with a decent set of tires, you will not get far. Either the truck will come to a stop or something will break.

If you have small enough tires, slick enough ones, or huge amounts of horsepower, you may be able to drive along scrubbing the tires. But for most trucks its not doable.

I came out of a bad bog one time headed to town. After I hit the dirt road, I forgot to shift out of 4hi. I thought the truck was a little sluggish going down the dirt road, but did not think a lot about it.
Had I checked the rear view mirror, I would have seen how my tires were tearing up the road. I saw it when I got back.
Not deep gouges, but lots of disturbed dirt. I looked like I was spinning out the whole way.

I hit the highway, and the truck really started to slow down.
After about 100 feet or so, despite my giving it gas, it was down to a crawl.
I took my foot off the gas, and the truck slammed to a stop. I darn near took a chunk out of the steering wheel with my teeth.

In fact, given all the mud and water I had been through, it stopped quicker than I could have with the brakes<G>.

I got out and looked all under and around it. Couldn't see a thing wrong.
I noticed my hubs were locked, and figured I would unlock them while I was there.
Could not turn either one.
Got back in the truck, and found the shifter in 4hi.
Could not shift out. Put the truck in reverse, and started tugging on the shifter as I backed up. The whole shifter system Moved about 3 inches as I was backing up. After I got the strain off it, it shifted out of 4wd, and I was able to unlock the hubs.

I'm not sure what would have happened if I had forced it, but it would not have been good.
I was running 12.50/33s. I'm sure with smaller tires, they would have slipped and I could have kept going. But I would not have wanted to go far.
In snow, ice or dirt, its doable, but still a strain.

J.

 

[dyeager535]

Binding is not the right word for it. Try total lockup.
If you run on dry pavement with the 205 in 4wd and the hubs locked, with a decent set of tires, you will not get far. Either the truck will come to a stop or something will break.

This is my take on it. I use 4WD when I HAVE to...its nice to have something as a backup, not find out I've got problems when I'm already in 4WD.

I don't know about anyone else, but my t-case is a 1991 205, and on DIRT roads (or my gravel driveway) if I have it in 4WD, and turn, for even 5ft, the drivetrain will be so bound up that the hubs can't be unlocked, nor can the 205 be shifted out of gear.

Usually driving in reverse will "unbind" it enough that I can unlock everything.

I just did this last night in my driveway, I was trying to drive over a refrigerator (don't ask) and with the wheels turned one direction as far as possible, and no more than 5ft forward travel, I couldn't turn the hubs out or get the case out of 4wd.

Hitting snow/ice with a lot of drivetrain bind would likely allow a wheel to slip enough to unbind (which is what GM counted on when using 4wd outside of the 203), but if it doesn't, eventually it WILL break something.

 

[moneypit_K5]

This is my take on it. I use 4WD when I HAVE to...its nice to have something as a backup, not find out I've got problems when I'm already in 4WD.

Wait wait wait, your opinion isn't relevant here, we are talking about harsh northern washington weather. you wouldnt understand how hard it is to drive in it.

 

[dyeager535]

Last year, we had five full days of snow on the road! My Hyundai couldn't even get out of my driveway! It was terrible!

Granted though, if you travel over the passes and into Eastern Washington in the winter, it CAN be pretty nasty. But if you need 4WD at 55, my opinion is you are being reckless. Far too many accidents on the pass in the winter from going way too fast for conditions, Subaru or not.

If I'm in 4wd going over Snoqualmie, I'm going 35 at best. If I can go faster, I don't need 4wd. If I anticipate needing 4wd, I slow down to a speed where I know I can shift into 4wd if necessary. I'm a bit cautious, but that's because my actions affect everyone else on the road, and vice versa. Those ABS vehicles, for all the complaints, can still surprise you at how fast they can stop, and you can't.

 

[6.2Blazer]

Binding is not the right word for it. Try total lockup.
If you run on dry pavement with the 205 in 4wd and the hubs locked, with a decent set of tires, you will not get far. Either the truck will come to a stop or something will break.

If you have small enough tires, slick enough ones, or huge amounts of horsepower, you may be able to drive along scrubbing the tires. But for most trucks its not doable.

I came out of a bad bog one time headed to town. After I hit the dirt road, I forgot to shift out of 4hi. I thought the truck was a little sluggish going down the dirt road, but did not think a lot about it.
Had I checked the rear view mirror, I would have seen how my tires were tearing up the road. I saw it when I got back.
Not deep gouges, but lots of disturbed dirt. I looked like I was spinning out the whole way.

I hit the highway, and the truck really started to slow down.
After about 100 feet or so, despite my giving it gas, it was down to a crawl.
I took my foot off the gas, and the truck slammed to a stop. I darn near took a chunk out of the steering wheel with my teeth.

In fact, given all the mud and water I had been through, it stopped quicker than I could have with the brakes<G>.

I got out and looked all under and around it. Couldn't see a thing wrong.
I noticed my hubs were locked, and figured I would unlock them while I was there.
Could not turn either one.
Got back in the truck, and found the shifter in 4hi.
Could not shift out. Put the truck in reverse, and started tugging on the shifter as I backed up. The whole shifter system Moved about 3 inches as I was backing up. After I got the strain off it, it shifted out of 4wd, and I was able to unlock the hubs.

I'm not sure what would have happened if I had forced it, but it would not have been good.
I was running 12.50/33s. I'm sure with smaller tires, they would have slipped and I could have kept going. But I would not have wanted to go far.
In snow, ice or dirt, its doable, but still a strain.

J.

You need to fix your truck.......or quit making up stories.......seriously, the issues you describe above are no where close to what happens in the real world on a properly setup truck (ie. matching tires and gear ratios).

 

[6.2Blazer]

I still say you guys are wack for "needing" 4x4 on level ground on pavement no matter how Icy. as long as when you hit ice your smooth on the accelarator its not gonna slide.

and if your already sliding 4x4 isn't gonna help you unless you get lucky and can accelarate out of your skid

Well, everybody has a right to their opinion. Heck, I know people that have cars with traction and stability control that always turn them off because they "don't need them" and they say they will "turn them on when it's needed".......come on now, let's get real.

I still say it makes perfect sense to run in 4wd when the roads have sporadic icy or snowy spots. I don't run any faster down the road when the weather is bad regardless of whether the vehicle is 2wd or 4wd, but still being in 4wd helps the handling of the vehicle and can prevent the vehicle from sliding. It is also much easier to recover from sliding when in 4wd.......if you know what you are doing.

I also don't see anybody really stating the "need" 4wd to make it from point A to B, but if you have it and it helps, why not use it?

 

[Fordum]

I would like to see what you call a properly setup truck.

As for matching tires, I imagine that when I bought the '33s they were exactly the same size.
Not sure though since I did not measure them with a Micrometer.
But, after a few weeks of driving I suspect that they wore differently. Especially front to rear.
So they are going to travel different distances per revolution.

I suppose a properly set up truck involves having a section of the frame that will expand and contract as need be so the front of the truck can move different distances.

Also, as for the gear ratios, I suppose you are aware that different makes and models of trucks have different ideas about that.

For instance you know that all the the early Jeep models have a front end that is a hundredth faster than the rear, right?

For instance, if you have a 4:10 on the front, you would have a 4:11 on the rear.
There are still some makers that do this, although I could not come up with a list right now. Toyota, I think used to do it and may still do.

But, even with the same ratio front and rear, I think that you would agree that the front and rear axles of a 4wd truck are going to move different distances per revolution just due to minor differences in tire diameter.

And that is in a straight line. When you turn a corner, all bets are off. Each tire is going to go a different distance per revolution.

OK, I know that last is not exactly correct, since the circumference of the tires will not change during a turn, but the outside front tire will move the farthest, making a big circle, and the inside rear will hardly move at all.

At any rate, I think you will agree that when going down a paved road, the front axle and rear axle have to turn at different speeds just due to the wear differences in the tires.

SO, if the front and rear axle are locked together by a locked transfer case and forced to turn at the same speed, and if the tires have a large amount of traction due to being on dry pavement and they have a good amount of mechanical advantage over the axles due to being of large diameter, then, what do you think will give when they are forced down the road?

All I know is, it happened to my truck with me driving it, I have seen it happen to others trucks, and I saw an aluminum transfer case explode when a fellow was using 4wd on dry concrete to pull his boat up a boat ramp.
Practically a new truck.
I pulled up real quick and hooked my winch to his truck so he could take his foot off the brake.
Later, I pulled him on up the ramp and off to the side so he could call a wrecker.

As for it not happening in the real world. Assuming that you have a transfer case that has no differential in it, ( such as a 205 ), I would invite you to lock your hubs and put your transfer case in 4HI, and drive 1/4 mile down a paved road with good tires.

However, since I do not believe in tricking folks into damaging their vehicles, I sincerely ask that you do not try this.
Unless your tires slip on the pavement, in which case you need better tires, you WILL break something on your truck if you have enough horsepower. And I do not want that to happen.

J.