4WD binds on sharp turns?

[dbsoundman]

I have a 2000 SR5 which does not have locking differentials from what I can tell. If I put it in 4H, I can pretty much drive normally, but if I'm maneuvering with the wheel turned all the way to the left or right (like in a parking lot), the wheels seem to bind up and I have to turn the wheel back in order to keep going. Is this normal, and if so, why? Am I just reaching the limit of the limited slip differential or is something else going on? Thanks for any info!

 

[nissanh]

It is normal. Use 4x4 only in soft surfaces (snow, wet or mud).

 

[the great him]

yeah so, its also dark when the sun goes down...

 

[the great him]

its the normal binding of the transfer case, just like your inside and out side tires will travel a different path, and distance while in a turn, each set of tires per axle ie front tires and rear tires will travel a different perspective path as the vehicle turns. these 4 different paths converge at the transfer case when in 4wd thus making the binding amplified and they fight each other. if there is no need to be in 4wd on hard serfaces such as pavement or concrete then i would recommend staying in 2wd. its just less wear on things

 

[dbsoundman]

Thanks, the manual doesn't make it super clear how flexible the 4WD mode actually is, and whether it's really usable on dry pavement. I'll keep it off unless it's wet or offroad from now on!

 

[Forrrrest]

Ha he said wet

 

[dbsoundman]

OK, so to bring this back up, I'd really like to understand what's going on with the vehicle when it's in 4wd...is there a limited differential, so that the right side and left side wheels can move at different speeds up to a certain point? I'm new to all this and I'm trying to figure out the difference between AWD, 4WD, and 4WD with a locker on the rear or front differential...

 

[Park]

Normally, explaining stuff like this annoys me, but in all fairness it can be confusing. Our trucks aren't Subarus, 4wd prevents the front wheels from moving at different speeds so when you turn, it causes the differential to bind. Heres a link that may help:
https://www.youtube.com/watch?v=-2xfkPT2A0k

 

[JB.]

OK, so to bring this back up, I'd really like to understand what's going on with the vehicle when it's in 4wd...is there a limited differential, so that the right side and left side wheels can move at different speeds up to a certain point?

In 4wd with a locked center connection (traditional 4wd or locked center differential) the front and rear drive shafts must turn at the same speed. During a turn, the combined speed of the two front wheels should be greater than the combined speed of the two rears because of a longer turning arc, and so the front drive shaft turning those wheels should also turn faster than the rear drive shaft. If you're thinking the open differentials on the front and rear should take care of all this, they don't. Their effect only operates on the axle they're on. So, in 4wd -- with power applied to the engine, the wheels turned, and the tires having traction -- a driving force develops on the drive shaft in the rear and a braking force on the drive shaft in the front. Those opposite twisting forces, until released by a slipping tire, come together at and put pressure on the transfer case. That's why it feels like you're driving with the brakes on when trying to get the truck moving with the wheels turned sharply.

 

[dbsoundman]

OK, so let me try to get this straight...does a stock 4runner without the differential lock button from the factory (i.e. my SR5) have a center differential, or does it not? Based on my experiences I'm guessing that mine does NOT have a center differential, hence the turning problems on dry pavement. Also, that would mean that the models with the button are effectively AWD without the button engaged...right?

 

[PitbullRescuer]

Somewhat off topic but why are you using 4WD on dry pavement?

 

[BlackCat914]

OK, so let me try to get this straight...does a stock 4runner without the differential lock button from the factory (i.e. my SR5) have a center differential, or does it not? Based on my experiences I'm guessing that mine does NOT have a center differential, hence the turning problems on dry pavement. Also, that would mean that the models with the button are effectively AWD without the button engaged...right?

no, you're locking the rear diff in place, meaning both axles are getting the same amount of power. They are not able to spin at different speeds when going around sharp turns, causing the binding feeling. It can also cause an axle to snap of they bind too much. (the rear locker, that is)

There is no need for 4x4 on dry pavement, it's hard on driveline parts when you do what you're doing, and under certain circumstances, can cause a ton of damage.

 

[Gerdo]

Differentials (on the axles) allow for the right and left wheels to spin at different rates.

A differential locker locks both wheels together and even if the vehicle is going around a turn, both wheels will continue to spin at the same rate. These tires will bind till one breaks loose and squeals.

A conventional (older style) transfer case is locked (when in 4wd), front driveshaft to the rear driveshaft. This will not allow for any difference in rotation and there will be binding on turns.

Some newer transfer cases have a differential in them and allow for the driveshafts to rotate at different rates (when unlocked). This type has a center diff lock. This locks the transfer case which then acts like a conventional transfer case.

Differentials (in the transfer case or axles) will send power to the wheel with the least resistance. This means that, in 2wd, if you have one drive tire on ice and the other on dry ground, you may be totally stuck due to the wheel on the ice spinning and receiving all the power. Likewise, if you have open/open axle diffs and the center diff (transfer case) diff unlocked (open) and one tire on ice, you could get stuck.

The center diff open is nice that it allows you to drive on patchy slick roads and not get binding. You will not have as good of traction as if when the center is locked.

Ultimate traction, everything locked (both axles and the transfer case). This will also cause the most binding.

Now a disclaimer. Locked axles will cause (on slick surfaces) that end of the vehicle to slide out easier. Especially going around corners and off chamber trails. I was following a locked rig across a slanted snow covered trail. That rig slid way off trail. I followed, open/open, and just drove thru without much issue.

True AWD locks the 4 wheels together with viscus coupling. Newer/more sophisticated AWD, this coupling is electronically controlled.

 

[Greg_Canada]

1999-2002 Limited 4runner's have multi-mode 4wd, where you can do 2HI, 4HI, 4LOW and AWD. If you don't have a limited, you shouldn't be using 4WD on dry pavement.
The multi-mode t-case's have a torsen limited slip differential installed, and you can run this on dry pavement (i use mine when there is light snow or heavy rain). 4HI is best offroad or heavy (constant) snow. A locking differential is similar to putting the t-case into 4HI... it locks both front and rear output shafts together so they spin the same speed. AWD lets front and rear shafts spin different speeds so you can drive on higher traction surfaces without binding.

 

[mikebontoft]

nice little read... I'm glad I drove 250 miles at highway speed on dry pavement stuck in 4hi. wondered why it was a little "bumpy" didn't think it was still in 4wd, the light was off. I know better now.

 

[dbsoundman]

Okay, so when I put my SR5 in 4WD, it has a conventional transfer case, so the center differential is locked, but the front and rear diffs are still open, correct? Not trying to be a block head, just making sure I know what's going on in my vehicle.

Also, I don't drive with 4WD on dry pavement, except once not long after I got it, to see what happened.

 

[rebelbowtie]

Okay, so when I put my SR5 in 4WD, it has a conventional transfer case, so the center differential is locked, but the front and rear diffs are still open, correct? Not trying to be a block head, just making sure I know what's going on in my vehicle.

Also, I don't drive with 4WD on dry pavement, except once not long after I got it, to see what happened.

You don't have a center differential

 

[BlackCat914]

Okay, so when I put my SR5 in 4WD, it has a conventional transfer case, so the center differential is locked, but the front and rear diffs are still open, correct? Not trying to be a block head, just making sure I know what's going on in my vehicle.

Also, I don't drive with 4WD on dry pavement, except once not long after I got it, to see what happened.

In factory trim, your specific vehicle can't have anything but open differentials. Putting the vehicle in 4x4 simply causes the transfer case to send power to the front differential as well, which in turn, powers the front wheel. Your vehicle only has a front differential, rear differential, and a transfer case.

 

[dbsoundman]

In factory trim, your specific vehicle can't have anything but open differentials. Putting the vehicle in 4x4 simply causes the transfer case to send power to the front differential as well, which in turn, powers the front wheel. Your vehicle only has a front differential, rear differential, and a transfer case.

Thanks, that's what I was looking for!

 

[daftwager]

I wish i had gotten to this thread sooner. Bought a 96 SR5 4WD and had the tail slide out on me in the wet. So i popped it into 4HI and drove about 60miles on the freeway...

Just as I was pulling into my drive way i got the distinct smell of burning gear oil wafting through the cab and white smoke coming from under the hood. My front diff was leaking gear oil and you could tell from the metal fragments in the oil it was totalled. Fast forward to today and I have a replacement front diff installed.

Lesson learnt - 4HI on these vehicles isn't something you should be doing on dry surfaces or for that fact at high speed. The manual says to put the vehicle into 4HI once a month to keep the front carrier assembly lubricated but im going to be hesitant at doing that in the future.

This thread was very helpful in understanding the diff arrangements, wonder if it should make its way into the sticked post for first time buyers along with some health warnings.