Hey all,

I'm having some 4WD issues with my 92 4Runner that hopefully someone can help me with. I've noticed that whenever in 4WD Hi(have not tried low range), and making a turn at almost full steering lock, I hear an extremely loud "pop". This "pop" can be heard way over the stereo and even makes the car vibrate. Furthermore, whatever is causing this makes the truck come to a pretty quick halt if I'm only going 5 MPH or so.

For example, when pulling out of my driveway one day, I had the truck in 4WD Hi as it was raining heavily outside. I put the tranny in reverse and started to back out, ending with a turn at full steering lock. As I was backing up, I heard this popping noise and it stopped my truck so quick I thought I had hit something behind me. I can get the truck to move again by giving it alot of gas and letting the clutch out slow, but still the popping remains. This has happened to me on the trail as well.

I know something is wrong here...there has to be. So far this has been nothing more than an annoyance, however I know a sound like that can't be good. Has anyone experienced this? It's not the common steering stops problem as with most 2nd gens as this only happens in 4WD. I don't think it matters which way I turn the truck, however I mostly hear it when turning left (or backing out right).

Any comments or suggestions would be helpful.

 

Usually when it does that it is doing it because of your front & rear binding.
That is most often caused by not having enough slippage when the 4WD system is engaged.

I can get mine to do that do on pavement and try to turn, or back up.
The wheels have to have some slippage such as ice, snow, or a trail.

But you say it's doing it on loose gravel or dirt on a trail too?
Mine has acted extactly as you described when you were backing up.

The only time I engage mine is in ice, snow, or when off pavement and in dirt.

 

I drive a '91 4Runner, and I get the same thing (I think) when I have my steering wheel cranked while in 4WD. The sound mine makes is like when the points on the control arms (I think that's where they are, it's where it'll make a metal to metal type sound when you crank your wheel and go forward) I believe that it's a normal sound because when you engage 4WD (high or low) it must do something up front that won't let you crank as far as when you're in 2WD (Someone PLEASE correct me if I'm wrong, I'm just guessing here )

I remember when I had my '93 Jeep Wrangler that when I was in 4WD (high and low) that it would make the same sound when I cranked my wheel and drove.

Hopefully someone else can explain it a lot better than I did (if I'm right of course )

-Braden

*EDIT* Dang Corey you beat me

 

i THINK i saw a post on this... let me look...

it might be... i dont know. something in your transfer case/diff getting jammed up. ill let someone else answer, and keep looking for the thread.

haha.. turns out, it is your thread

i replied to this one too... maybe this one will get some more replies.

 

wow while i was looking for that post, you guys replied.

also, you shouldnt need 4WD when its raining out. 4runners are pretty heavy, and you probably wont loose traction in rain. unless you hyrdoplane, in which case you would have to be going really fast to do that in a 4runner.

i guess i am wrong about driving on pavement in 4WD. it seems to me like you should be able to without any problems. guess im wrong. looks like you got some better responces on this thread than on the last one.

sorry i didnt help!

 

This is one of the most common questions among the newer Tacoma crowd.

What you are experiencing is the drive system unloading. When you put it in 4x4 mode, the mechanics of the system want to see one of two things, either all the wheels travelling in the same direction at the same speed or periodic spots where different wheels loose traction and can "unload". What you are experiencing is completely normal for 4x4 systems, other than "AWD" 4x4 systems. When neither of the above two conditions exists, the drive will find a way to unload the torque on a wheel to balance out the system.

Is it good for it? No, but it's not necessarily harmful. You are not likely to break anything unless you are really on the the throttle, but it can be taken as a sign that you might not *need* to be in four wheel drive at that point.

 

There is nothing really stopping you from turning, you still have the same range of steering, but the "heavy" feeling you are detecting is from the front axles being engaged and having torque on them. The further you turn the wheels, the more angle you are putting on the CV's, thus the more effort that has to be expended to get and keep it in a turn position. If you crank your wheels hard over in a parking lot, then put it in 4x4, you will feel a natural tendancy for it to try to straighten out. It's much, much more difficult even beyond that when you have a selectable locker in the front You have to be careful not end up with "Popeye" arms when turning with the locker engaged heheheh

 

I get the same noises too. The last time I remember it, I was pulling a bush out of my yard - root ball and all - ended after two good tugs on dry pavement and turned in 4h. Slippage and unloading sound like what was happening. I feel better knowing why now...

 

I'm with ya Cebby, it makes me feel better now what it is too. Thanks for the info WATRD

-Braden

 

:eek:
Um, guys? Our rigs have part time 4wd systems, and as such the design cannot differentiate between the front and rear axles. These systems are never to be used on high-traction surfaces such as pavement wether wet or dry, under any conditions. Those loud noises and tires chirping and hopping are trying to tell you somethings wrong. If you continue to abuse them in this way you will eventually break something expensive. If you're lucky you'll pop a CV joint, or you could end up destroying the transfer case.

 

That's a bit reactionary, don't you think?

While I agree that it's a bit silly to use 4x4 on pavement except in some very narrow circumstances, I think you have overstated the danger. "Eventually" is WAY too strong. Could you damage something by romping on the throttle and binding up the system? Sure, I have snapped CV's and U-Joints from that very thing. But it is not very likely to happen in light duty, on road use. Toyota builds rigs with "shift on the fly", not because of people who use their rigs like I do, but rather for those who want a bit more security when the road conditions deteriorate. That's why you can shift those systems into 4x4 at anything less than 60 MPH, a speed that you are unlikely to encounter off road. Toyota EXPECTS it's four wheel drive to be used on pavement and it is up to the job. The axles will continue to unload torque when it builds up and life goes on

 

No, I don't think so. Some of the highest stresses the drivetrain can see are when binding it up in this way. Transfercases can and have been cracked open by doing this. The intended design of the "shift-on-the-fly" system is so that the driver doesn't have to stop and get out when they get to the snow at the top of a pass or when they leave the pavement for loose dirt/gravel roads. It is not meant to be used in everyday city driving.
If the road conditions are deteriorating, the driver should first slow down.
No, Toyota does not expect it's part-time systems to be used on pavement, and if you look in your owner's manual you'll see this very same warning. Their full-time systems in the Landcruisers however are designed with a center differential so that they can be used at any time on any type of surface.

Not trying to start an argument here, just trying to clear up some bad advice...

 

Thanks for all the replies! The main reason I use 4WD is because it has been raining very heavily here and traction is horrible, especially with my 225s (which are going to be replaced ASAP). As far as slowing down goes, I skid out when making a left turn from a stop light, sometimes even if it's not raining. That coupled with the fact that the rain is unrelentless, I must use 4WD when turning. I guess I can keep switching it on and off, if there's alot of stress being placed on the transfer case.

BTW- Does this mean I shouldn't even use 4WD on the trail? I noticed this popping occurs on the trail as well.

 

Slowing down would seem to be "common" sense and not really relevant to this conversation, in my humble opinion.

I can't believe you hold the owners manual in such high esteem. It is much more about liability than it is facts. It also says that you should only operate the rear locker in 4lo, you should not change tire sizes from stock, you should not modify your rig outside of manufacturers specifications, your oil needs to be changed religiously at 3000 miles and so much more... We have only met once and I don't claim to know you or your rig, but from your avatar, it looks like you have disregarded at least some of their advice already...

Agreed and same here. But I must disagree with the strength of your words. The fact of the matter is that the shift on the fly system can be engaged at "up to 62 MPH", that would seem to be in excess of the speed required in entering a ski area or transitioning to a gravel road. I think that stating that 4x4 mode should never be used on pavement is too strong. The system is beefy and will easily take the slow speeds these guys were talking about.

I totally agree that there is little need to blast down the hiway at 80MPH in four wheel drive, but driving around on a wet, oil soaked road provides plenty of opportunity for the drive system to unload torque. It is similar to the guys who drive around with their differentials "Lincoln locked". The wheel with too much torque WILL unload. With a touch of restraint, no harm will be done in the process.

 

Packed-dirt is ok for 4wd, though 99% of the time it's not necessary, anything looser is fine. If it's popping that often you should look into wether something is already broken. Are you sure you're not hearing the classic steering stop noise? Does it ever make the noise when going straight?

 

That is weird you hear it popping even on trails.
I have mine in 4H & 4L on stuff like this all the time, and I get none of the binding or popping you are getting.

 

In this day and age people think that because they have 4wd they're invincible. The problem is that people don't slow down any more.
I don't, I was merely using it as an example.
The highest stresses the drivetrain will see on-road in 4wd are in slow tight turns (such as backing out of a driveway) where the tires are not able to easily scrub off the extra torque.

Anywho, I can see this is going nowhere. You have your views and I have mine. Everyone else can decide what they want. Meanwhile let's get this back on topic...

 

Damn, steal my thunder I was just going to suggest that it might actual be his steering stops making the noise.

Test the theory - do a turn with full lock and see if you hear the same noise. Preferably somewhere where the suspension might have some travel ( i.e. over a speed bump).

I got so damn tired of replacing those crappy plastic caps on my old truck. I worked in the city so I had to use full lock on my Xtra cab to park every day.

hope that helps

 

take it easy guys!!!

i dont know who to agree with. lets call up toyota and ask. it seems funny that your front and rear wheels can't turn at different rates. is that what your saying shane? im not really sure. maybe it is the steering stop i dont know. good luck man.

 

Correct, in part-time systems the front and rear axles are locked together so they're forced to turn at the same rate. When you turn the front axle travels through a larger arc than the rear, essentially travelling a longer distance, and that's where you get the binding. However this binding shouldn't cause any popping or other metallic noises, only tire hop as the torque is released.