Own a Trailblazer...has 4WD..first vehicle with it ...haven't been off-road with it yet. Was out shopping today and I was sitting at a round-about waiting to go. I decided to put it in (4WD High) and drive it like that into the parking lot of the shopping center. I turned sharply into a parking space when all of a sudden the truck locked up and wouldn't move anymore so I turned off the 4WD and heard %&*#@!....What did I do wrong?
School me on 4WD...
- Thread starter Warstud
- Start date
- Status
You used the 4WD on dry pavement. Part-time 4WD means the front wheels and back wheels rotate at the same speed because there's no center differential. Unless at least one wheel slips, you can't turn. Trying to turn creates a lot of pressure in the driveline and with that pressure comes friction. Your engine eventuall doesn't have enough power to overcome it unless a tire slips or something breaks with a nasty expensive bang. If there's an owner's manual in the glove box, check it out.
JHZR2
Staff member
Yep, you got "binding". Dont do that or it can become an expensive mistake.
4WD, though misrepresented (IMO) on vehicles like Honda CR-Vs and such, is, to me at least, a part time system with or without locking hubs, which spins the wheels all at the same speed and relies on LACK of traction to operate under conditions like turning.
THis is opposed to AWD which uses a clutch or viscous link to allow more varied use and more continuous duty.
My representations may be shallow, but IMO/IME, only "auto" 4wd systems and AWD systems can be used all the time. Real 4WD systems can not.
4WD, though misrepresented (IMO) on vehicles like Honda CR-Vs and such, is, to me at least, a part time system with or without locking hubs, which spins the wheels all at the same speed and relies on LACK of traction to operate under conditions like turning.
THis is opposed to AWD which uses a clutch or viscous link to allow more varied use and more continuous duty.
My representations may be shallow, but IMO/IME, only "auto" 4wd systems and AWD systems can be used all the time. Real 4WD systems can not.
Don't ever, ever drive in 4WD on hard surfaces, as the differences in distance travelled by the individual wheels (and differences in effective diameter) wind up all of the drivetrain components until the wheel with the least traction starts to slip.
The axles will have equivalent torque on them to you breaking traction on dry pavement, i.e. as much as is physically possible.
Then as you add movement and speed, you end up with a phenomenon called "circulating power"...the differentials and transfer cases are exeriencing the same loads as if you were doing a 4 wheel burnout, at the wheel speed indicated on the speedo.
There's probably 200-300kW "Circulating" from one end of the vehicle to the other,while your engine only has to provide enough grunt to overcome the losses of that power...drive train components get very hot very quickly, and mating faces can be destroyed quickly.
The axles will have equivalent torque on them to you breaking traction on dry pavement, i.e. as much as is physically possible.
Then as you add movement and speed, you end up with a phenomenon called "circulating power"...the differentials and transfer cases are exeriencing the same loads as if you were doing a 4 wheel burnout, at the wheel speed indicated on the speedo.
There's probably 200-300kW "Circulating" from one end of the vehicle to the other,while your engine only has to provide enough grunt to overcome the losses of that power...drive train components get very hot very quickly, and mating faces can be destroyed quickly.
Traditional hi/low range 4WD systems use a transfer case, usually chain driven, to split the output from the transmission between the front and rear wheels. It relies on some slippage occurring at the wheels such as mud, loose dirt, or snow to work. You can get away with driving in a straight line on pavement in 4WD, but making a sharp turn the speed of the wheels will vary greatly so you get binding.
My Explorer had a primitive form of auto-4WD with low range that could engage and disengage the front differential with a vacuum disconnect if the front wheels were slipping. It used a traditional transfer case though and it did not like pavement. A couple times it shifted itself back into 2WD only mode when I tried it on pavement (light flashed then went off).
My Explorer had a primitive form of auto-4WD with low range that could engage and disengage the front differential with a vacuum disconnect if the front wheels were slipping. It used a traditional transfer case though and it did not like pavement. A couple times it shifted itself back into 2WD only mode when I tried it on pavement (light flashed then went off).
The Jeep Grand Cherokee has a real transfer case and has 4WD H, L and PT. Its my understanding that only in PT are all the wheels locked up. In normal 4WD H they are not and one could safely drive on dry roads. This is a SelecTrac.
Originally Posted By: Shannow
Don't ever, ever drive in 4WD on hard surfaces,
That's good advice for 99% of the folks here. There are areas, such as Moab, UT (I'll heading back this year), where you're in 4 low all day, every day and it's like being on pavement.
Low range gives the engine more advantage to turn your tires on hard surfaces, although you still get some steering feedback. Typically, the tires bark when taking corners and with 4340 alloy shafts in 3/4 ton axles with Detroit Lockers, I'm not worried one bit.
Don't ever, ever drive in 4WD on hard surfaces,
That's good advice for 99% of the folks here. There are areas, such as Moab, UT (I'll heading back this year), where you're in 4 low all day, every day and it's like being on pavement.
Low range gives the engine more advantage to turn your tires on hard surfaces, although you still get some steering feedback. Typically, the tires bark when taking corners and with 4340 alloy shafts in 3/4 ton axles with Detroit Lockers, I'm not worried one bit.
Warstud, I also want to offer some friendly advice - Don't go wheeling alone, especially if you're not equipped or have limited recovery experience and gear.
Warstud -
I have a 1999 Blazer. The S-10 version, not the full size. So it is similar to yours. I use the Auto 4wd, when there is a little snow out. I use 4WD High, when there is a lot of snow, or if Im on a mud road. 4WD low, is very rarely used, at least with me. I do go out on a gravel road, the first part of every month, and run it through all the different configurations. Just to keep everything freed up, and "fresh". I do agree with the others, DO NOT use the 4WD, in high or low, on dry, hard surfaces.
Oh, and to answer your question - I don't believe you need to be in neutral when going from 2WD to 4WD, as long as it is in "high" gear. NEVER try to shift into 4WD low while moving. Always be stopped, with the tranny in Neutral. Your transfer case will grenade if you don't.
I have a 1999 Blazer. The S-10 version, not the full size. So it is similar to yours. I use the Auto 4wd, when there is a little snow out. I use 4WD High, when there is a lot of snow, or if Im on a mud road. 4WD low, is very rarely used, at least with me. I do go out on a gravel road, the first part of every month, and run it through all the different configurations. Just to keep everything freed up, and "fresh". I do agree with the others, DO NOT use the 4WD, in high or low, on dry, hard surfaces.
Oh, and to answer your question - I don't believe you need to be in neutral when going from 2WD to 4WD, as long as it is in "high" gear. NEVER try to shift into 4WD low while moving. Always be stopped, with the tranny in Neutral. Your transfer case will grenade if you don't.
Last edited:
Here's what I do, although I'm sure everyone has their own opinions. I drive a Tahoe at work with a similar auto/4H/4L system.
1. Light snow/ice and driving gravel or dirt roads that are slightly muddy or wet.
2. Deep snow or seriously muddy roads/trails.
3. Only used it once. I was on dry pavement and using my vehicle to pull another out of the ditch. The low ratio helped for sure, but I've found it too torquey for normal driving, even off-road unless your're doing some serious rock climbing.
Your owners manual lilely states the maximum speeds for these selections, and I would go by that, but I don't do more than 55 in auto, 45 in 4H, and 15 in 4L.
You should be stopped and in neutral when switching to 4L, but can make the switch to auto or 4H while driving at a moderate speed. I usually do it while coasting because it seems easier on the transfer case. This is probably in your owners manual as well.
1. Light snow/ice and driving gravel or dirt roads that are slightly muddy or wet.
2. Deep snow or seriously muddy roads/trails.
3. Only used it once. I was on dry pavement and using my vehicle to pull another out of the ditch. The low ratio helped for sure, but I've found it too torquey for normal driving, even off-road unless your're doing some serious rock climbing.
Your owners manual lilely states the maximum speeds for these selections, and I would go by that, but I don't do more than 55 in auto, 45 in 4H, and 15 in 4L.
You should be stopped and in neutral when switching to 4L, but can make the switch to auto or 4H while driving at a moderate speed. I usually do it while coasting because it seems easier on the transfer case. This is probably in your owners manual as well.
Originally Posted By: Zaedock
That's good advice for 99% of the folks here. There are areas, such as Moab, UT (I'll heading back this year), where you're in 4 low all day, every day and it's like being on pavement.
Low range gives the engine more advantage to turn your tires on hard surfaces, although you still get some steering feedback. Typically, the tires bark when taking corners and with 4340 alloy shafts in 3/4 ton axles with Detroit Lockers, I'm not worried one bit.
True, but there;s a bit of sand too isn't there, and as you say, slow speed,low circulating power.
As to the chirping, my Nissan has an awesome LSD. In shopping centre carparks with polished concrete, you can feel the front push until the inner rear rolls over.
When to use 4WD ?
When off road, even on dry clay pan, I'm usually in 4WD.
Last winter when we had to drive through a "blizzard" with hard packed ice, I was in it.
Dug a hole in the sand, get in 4WD.
I DO do what Nissan tell me not to do which is to engage 4Low without front hubs locked in...only once or twice when I was more worried about riding the clutch on a hill.
Handy thing in manuals is ignition off with still in gear on hills, select lower gear with foot on brake, and ignition on and start movement on the starter motor...diesels fire straight up and up you go without having ever lost control of the wheels.
That's good advice for 99% of the folks here. There are areas, such as Moab, UT (I'll heading back this year), where you're in 4 low all day, every day and it's like being on pavement.
Low range gives the engine more advantage to turn your tires on hard surfaces, although you still get some steering feedback. Typically, the tires bark when taking corners and with 4340 alloy shafts in 3/4 ton axles with Detroit Lockers, I'm not worried one bit.
True, but there;s a bit of sand too isn't there, and as you say, slow speed,low circulating power.
As to the chirping, my Nissan has an awesome LSD. In shopping centre carparks with polished concrete, you can feel the front push until the inner rear rolls over.
When to use 4WD ?
When off road, even on dry clay pan, I'm usually in 4WD.
Last winter when we had to drive through a "blizzard" with hard packed ice, I was in it.
Dug a hole in the sand, get in 4WD.
I DO do what Nissan tell me not to do which is to engage 4Low without front hubs locked in...only once or twice when I was more worried about riding the clutch on a hill.
Handy thing in manuals is ignition off with still in gear on hills, select lower gear with foot on brake, and ignition on and start movement on the starter motor...diesels fire straight up and up you go without having ever lost control of the wheels.
Part time 4WD needs a slippery surface to function properly or the system will bind up. Binding can cause damage to the drive shafts u-joints and transfer case. It can be costly and dangerous. Only use 4WD when you need it.
Full time 4WD and AWD can be used all the time, they allow for operation on dry pavement.
Full time 4WD and AWD can be used all the time, they allow for operation on dry pavement.
I typed this all up need in pretty. Then my dad called, and when I answered the phone, it erased everything I typed. I'm gonna rip this out quickly before somebody else calls.
Full time 4X4 will automatically send power to the non primary drive axle as needed. It is ideal for people who do not know when to use 4X 4 or 2 wheel drive. My wife would be the perfect example.
AWD Functions basically the same way. With the only exception being, it can send power to specific tires rather then to the axles.
4X4 Should only be used by people who know how and when to properly use it. It should only be used when you expect to lose traction. And should be turned back off when the danger is passed. I have been told, that if you are traveling on long straightaways you should engage your 4 wheel drive just to keep the system loosened up.
I also see that through my phone I cannot scroll through and proofread. I hope this looks good.
Full time 4X4 will automatically send power to the non primary drive axle as needed. It is ideal for people who do not know when to use 4X 4 or 2 wheel drive. My wife would be the perfect example.
AWD Functions basically the same way. With the only exception being, it can send power to specific tires rather then to the axles.
4X4 Should only be used by people who know how and when to properly use it. It should only be used when you expect to lose traction. And should be turned back off when the danger is passed. I have been told, that if you are traveling on long straightaways you should engage your 4 wheel drive just to keep the system loosened up.
I also see that through my phone I cannot scroll through and proofread. I hope this looks good.
JTK
$100 Site Donor 2025
Originally Posted By: Warstud
...What did I do wrong?
As you know now, pretty much everything you stated in your post!
I owned a 2005 Trailblazer 4x4. Great winter 4x4 performance, but I hated the "auto" 4x4 option. It waits for the rears to spin, then slam/bangs in the front axle.
...What did I do wrong?
As you know now, pretty much everything you stated in your post!
I owned a 2005 Trailblazer 4x4. Great winter 4x4 performance, but I hated the "auto" 4x4 option. It waits for the rears to spin, then slam/bangs in the front axle.
- Status
Similar threads
