IDIOT Needs help determining 4WD & Center Diff Lock Status

[ehuesman]

Hi All,

Since I just became a 4Runner owner two days ago, I'm brand new to the forum. I've already done some searching on this forum and YotaTech for answers, but I'm not even sure what my problem is, so searching for an answer is kind of difficult. Just so you know my base of knowledge, I'm just a DIY guy, nothing close to an automotive expert. I've always done my own work, but always with the guide of a Haynes or Chilton's (in the old days). Nowadays I use YouTube and downloaded FSM's. I can do maintenance and minor tune-ups, but I've never done anything with a 4WD system (other than the maintenance of fluid, grease fittings, etc.).

Also, I apologize in advance for the long post. I try to be as descriptive as possible to help those who are helping me. If you don't want to read the long story, it boils down to these three questions:

(1) Without the use of the indicator lights in the dash, or the position of the 4WD push button, or the "feel" of the driving, how can I determine if my 4Runner is in 2H or 4H?

(2) Without the use of the indicator lights in the dash, or the position of the Center Differential Lock button, or the "feel" of the driving, how can I determine if the center differential is locked?

(3) With the transmission in neutral, and shifting the 4WD shifter from the "4L" position, past the "N" position, and into the "H" position, is it normal to hear gears grinding and have to somewhat force the shifter into the "H" position?

Here is the story that has led me to those two questions. I promise I'm not usually as stupid as these next few paragraphs are going to make me appear (I hope).

I've spent the last few weeks searching for my son's first car. Two days ago, I came across an '01 4Runner Limited 4WD with low mileage. Since I already own an '02 Tacoma Double-Cab 4WD, and I am a fan of the 3.4 V6 (and Toyota's in general), I decided to go check it out. While test driving the 4Runner, I saw the 4WD system appeared to be identical to the one in my Tacoma, at least in regards to the "4WD shifter" (is that the proper name?) next to the auto transmission shifter. I did notice the 4Runner had a center differential lock, versus my Tacoma having the rear diff lock.

While driving the 4Runner at about 20 mph, I pushed the 4WD button, but nothing happened. Nothing at all, no lights, no buzzing, and no difference in the feel of the driving. I then stopped the truck, put the transmission in neutral, then shifted the 4WD shifter up into the "4L" position. I put the transmission back into drive, and could immediately feel and hear the difference. It felt and sounded just like when I have my Tacoma in 4L 4WD. I pushed the center differential lock button, but again nothing happened. No lights, no sound. I stopped the truck, put the transmission in neutral, then shifted the 4WD shifter down to the "H" position. I had to push it into position, and I could hear gears grinding as I did so. I couldn't remember if that was what it sounded like in my Tacoma or not, because I don't really use 4WD that often.

The above set of circumstances led me to believe that since the push button 4WD and the push button center differential lock did not appear to be working, but the truck went into "4L", that the problem was something electrical, maybe even simple like a fuse (I now realize that was faulty logic and an utter display of stupidity). Everything else seemed good on the truck, so I went ahead and purchased it and drove it home.

After I got off work the next day, I went to the 4Runner and did a visual inspection of all the fuses. I did locate the 4WD fuse in the panel next to the steering wheel, but it looked fine when I took it out and inspected it. I also checked all the fuses in the box in the engine compartment. They all appeared to be in working order. A little disappointed that my fix wasn't going to be so easy, I got under the 4Runner and tried to rotate the front driveshaft, but it wouldn't turn. Believing that meant the 4Runner was in 4WD, I went over to my Tacoma and tried to rotate the front driveshaft. It turned very easily. Even though none of the 4WD indicator lights on the dash of the 4Runner were working, I still pushed the 4WD button in and out, trying to turn the front driveshaft with the 4WD button in both positions. I was never able to turn it.

At that point, I started fuming because I believed that since I could not turn the 4Runner's front driveshaft, but I could turn the Tacoma's front driveshaft, that meant the problem with the 4Runner's wasn't that it wouldn't go into 4H 4WD, but that it was actually STUCK in 4H 4WD. I began to suspect the seller's must have disabled the 4WD indicator light in the dash in order to hide the problem.

I called a buddy, who is not very familiar with Toyotas, but does have more automotive knowledge than me. He explained to me that when I was test driving the 4Runner, and put it into "4L", that even though I thought it was in 4L 4WD due to the change in feel and sound, that it was probably just in 2L. He said the sound and feel of 4L and 2L would be pretty similar. We then jacked up the front left wheel and was able to free spin it, which leads us to believe the 4Runner is NOT stuck in 4WD. My buddy stated the front driveshaft in his Dodge Ram is always engaged and turning, and engaging the gears inside the front axle, so he can never get under his truck and rotate the front driveshaft by hand. When he puts his Dodge into 4WD the wheels lock into the gears in the axle. He suggested maybe my 4Runner operates the same way.

Someone else told me this afternoon that jacking up one wheel and being able to spin it didn't necessarily mean the truck wasn't in 4WD. He said it could be a limited slip differential, which would enable me to spin one of the wheels, even in 4WD. He did qualify that opinion by stating he didn't know a lot about 4WD.

Another issue, that I'm guessing is related to all of the above, is the "VSC OFF" and "VSC TRAC" lights do not come on when the ignition is turned on. While searching the internet for solutions to my problems, I learned those two lights are supposed to come on, and then go off, after the ignition is turned on. The "VSC OFF" is also supposed to come on when the center differential is locked.

At this point, I'm not sure if the sellers disabled any of the dash indicator lights or not. My understanding is the 4WD indicator light would be blinking if there was a problem with the 4WD system that prevented it from engaging. I didn't see anything in my research that would explain why that indicator light would not come on at all. I also don't know if it is possible to lock the center differential if the truck is only in 2WD.

My primary concern is determining what state the truck is in right now, and since I can't rely on the dash indicator lights, I need to learn how to determine that by other means. Is the truck in 2H or 4H? Is the center differential locked or not? Honestly, I could go without a working 4WD system, but my understanding is that I don't want the opposite. Meaning, I think it's a bad idea to have a truck stuck in 4H all the time and/or have the center differential locked all the time. Of course, if fixing the 4WD is somewhat simple and inexpensive, then all the better.

If you read this far, thank you very much for your time. Any suggestions would be greatly appreciated.

- Eric

 

[csp]

The shifter position should tell you if it's in 4H or 2H. It's not like the two positions are 1/8" away from each other.

I didn't read it all, too much story and not enough getting to the point.

 

[concordcarlos]

I can only add a little to your question.

When I go into 4L , it does grind a little bit and does take a bit of thrust to get the lever into 4L.

My VSC light does go on when I lock the Center Diff.

Carlos

 

[ehuesman]

The shifter position should tell you if it's in 4H or 2H. It's not like the two positions are 1/8" away from each other.

I didn't read it all, too much story and not enough getting to the point.

Maybe I have even less of an understanding than I thought. I believe the 4WD shift only has three positions, from top to bottom: 4L --> N --> H.

The shifter is in the same position for 4H and 2H. So you're right, it's not like the two positions are 1/8" away from each other. They are the same exact position.

When I go into 4L , it does grind a little bit and does take a bit of thrust to get the lever into 4L.

Does it also grind when going back into the "H" position from the "4L" position?

 

[Sculsz]

Maybe I have even less of an understanding than I thought. I believe the 4WD shift only has three positions, from top to bottom: 4L --> N --> H.

The shifter is in the same position for 4H and 2H. So you're right, it's not like the two positions are 1/8" away from each other. They are the same exact position.



Does it also grind when going back into the "H" position from the "4L" position?

It will grind a little when you go back to "H".

To test if the vehicle is in 4x4, press the diff lock button on the left side of the steering wheel that looks like 4tires. Then put it in drive with your foot on the brake, turn your steering wheel all the way left or right, slowly release the brake (DO NOT HIT THE GAS), the truck should roll a little and eventually roll to a stop then as you turn your wheels straight again it should slowly roll again.

This will only work if it's in 4x4 with the diff locked. If it keeps rolling in circles, 4x4 is most likely not on.

This is how I test 4x4 vehicles before I buy them.

 

[Sculsz]

It will grind a little when you go back to "H".

To test if the vehicle is in 4x4, press the diff lock button on the left side of the steering wheel that looks like 4tires. Then put it in drive with your foot on the brake, turn your steering wheel all the way left or right, slowly release the brake (DO NOT HIT THE GAS), the truck should roll a little and eventually roll to a stop then as you turn your wheels straight again it should slowly roll again.

This will only work if it's in 4x4 with the diff locked. If it keeps rolling in circles, 4x4 is most likely not on.

This is how I test 4x4 vehicles before I buy them.

I forgot to mention that the ground surface must be dry.
Again... DO NOT HIT THE GAS while trying this on dry surface.

 

[csp]

My mistake then. Mine has separate positions for 2wd and 4wd.

Guess I failed to sift through the post enough to find the year.

 

[Unner]

Sounds like you have the multimode transfer case since you have the center diff lock button. I too did not read the entire post, too long. To put it in 4WD you just need to push the button on the side and then drive a little and you see the center diff light on the dash flash orange and then when it is engaged the 4 wheels will turn green. You should feel a slight change in the steering resistance, but not much overall. This is safe to run on dry pavement, it is essentially all wheel drive like this. Then when you push the center lock button it locks the center diff, duh, and operates like a traditional 4WD system. You should not drive on dry pavement with the center diff locked. This causes binding. To put it in 4 LO put the truck in neutral at a stop, leave your foot on the brake, and then slowly push the lever forward until it engages 4LO. This should feel much different than the other modes.

 

[ehuesman]

This will only work if it's in 4x4 with the diff locked. If it keeps rolling in circles, 4x4 is most likely not on.

Thanks, I'll try this out tomorrow morning. What is the center differential lock doesn't work though? When I press the diff lock button, there are no indicator lights on the dash. If the 4WD was engaged, but the diff lock wasn't working, would it still just roll in circles?

And thanks for the answer about getting the grinding when going back into "H".

 

[animator]

Raising all 4 wheels off the ground with a few jacks and some stands will be a no-BS method of seeing if you are in 4wd or not.


You should also hear a noticeable click when engaging/disengaging the 4wd. It is generally audible enough to clearly hear inside the vehicle. You should also hear a noise when engaging the center diff lock.


It is normal to hear a slight grind as you shift the tcase lever from 4l to 4h. Putting the transmission in N first, then shifting the tcase lever helps prevent this.

 

[StreetCreeper]

Perhaps a different approach would be to pull the dash cluster and inspect and replace the bulbs. There are many write-ups here on changing these bulbs.

If you find the bulbs to have been removed or tampered with--you will have a better idea of things.

 

[Unner]

I forgot to mention sometimes my center diff doesn't engage on the first press of the button either. Like animator said you should hear a slight thud when it is put into 4WD as well.

 

[ehuesman]

Raising all 4 wheels off the ground with a few jacks and some stands will be a no-BS method of seeing if you are in 4wd or not.

If I use jack stands to raise all four wheels off the ground, I would just put it in Drive and see if the front wheels turn, right?

Any way to tell if the center differential is locked? Can it be locked without the truck being in 4WD?

You should also hear a noticeable click when engaging/disengaging the 4wd. It is generally audible enough to clearly hear inside the vehicle. You should also hear a noise when engaging the center diff lock.

I'm familiar with the noise I should hear, I'm assuming it should sound just like my Tacoma. One of my questions is if the T4R is already in 4H, and is stuck there, and the seller disabled the dash indicator to conceal the issue that 4WD won't disengage.

It is normal to hear a slight grind as you shift the tcase lever from 4l to 4h. Putting the transmission in N first, then shifting the tcase lever helps prevent this.

I'm hearing the grinding noise even when putting the transmission in "N" first. You're saying I shouldn't hear any noise if I do that first?

Thanks for your help!

 

[ehuesman]

Perhaps a different approach would be to pull the dash cluster and inspect and replace the bulbs. There are many write-ups here on changing these bulbs.

If you find the bulbs to have been removed or tampered with--you will have a better idea of things.

I was thinking it may come to this, I was just hoping to not have to dismantle the dash. I've never done it before and have always had the belief you can never get it back together looking just right...like you could always tell it had been dismantled.

I forgot to mention sometimes my center diff doesn't engage on the first press of the button either. Like animator said you should hear a slight thud when it is put into 4WD as well.

I will take it out tomorrow and give it more time to engage 4WD and/or the diff lock. I'm used to my Tacoma, which has always engaged or disengaged basically immediately, but I've read other threads tonight where people talk about their T4R taking a long time to engage, sometimes up to 20 minutes! It also seems this is more common on vehicles that haven't had the 4WD used in a long time. I'm still not sure though if the 4WD dash indicator should be blinking during this delay of up to 20 minutes. My light does nothing.

Thanks for the input.

 

[Andy in Pa]

If I use jack stands to raise all four wheels off the ground, I would just put it in Drive and see if the front wheels turn, right?

Any way to tell if the center differential is locked? Can it be locked without the truck being in 4WD?



I'm familiar with the noise I should hear, I'm assuming it should sound just like my Tacoma. One of my questions is if the T4R is already in 4H, and is stuck there, and the seller disabled the dash indicator to conceal the issue that 4WD won't disengage.



I'm hearing the grinding noise even when putting the transmission in "N" first. You're saying I shouldn't hear any noise if I do that first?

Thanks for your help!

Ok, your starting to go in circles here...

Test #1-
Do you hear ANY clunking at all when you push the buttons? There should be a slight (but audible) clunk when pushing the buttons. If needed, have someone else push the buttons while you listen underneath.

Test #2-
Drive in tight circles on dry pavement... Does the front end drag considerably? If so, its in 4WD. If not, it still could be in AWD.

Test #3-
Get all 4 tires off the ground, and have a friend help you start spinning tires. When you turn both of the back tires, does the front driveshaft turn? If so, it is in AWD.

FYI-
When you go from 4H to 4L it will ALWAYS grind a little bit when the tranny is in neutral (it will grind ALOT if the tranny is in gear or in PARK, don't do that!!), possibly more than a little bit IF the tranny or transfer case isn't fully done spinning, or the gears don't mesh right away. This is common in any vehicle with a shifter. Sometimes it goes right in/out, sometimes it doesn't.

 

[ehuesman]

Ok, your starting to go in circles here...

I do feel a little bit that way...then again, everyone keeps telling me to drive in circles...

Test #1-
Do you hear ANY clunking at all when you push the buttons? There should be a slight (but audible) clunk when pushing the buttons. If needed, have someone else push the buttons while you listen underneath.

This has been done, nothing heard when either the diff lock or 4wd button are pushed.

Test #2-
Drive in tight circles on dry pavement... Does the front end drag considerably? If so, its in 4WD. If not, it still could be in AWD.

I just did this. Drove around in tight circles several times, in both directions. Everything felt normal to me, and there was no noticeable dragging. I thought 4WD (at least in 4H) and AWD were the same thing though. What is the difference?

Test #3-
Get all 4 tires off the ground, and have a friend help you start spinning tires. When you turn both of the back tires, does the front driveshaft turn? If so, it is in AWD.

I'll have to wait until later today to do this test. Does it mean anything that I can't rotate the front driveshaft by hand, while it is parked with the engine off and all tires still on the ground? I can rotate my Tacoma's front driveshaft when it is in this same condition. I don't understand the difference between the two vehicles' 4WD systems. I thought the only difference was the T4R has the center diff lock, and the Tacoma has the rear diff lock.

And thanks for the additional clarification on the grinding while changing gears with the 4WD shifter.

 

[Run 4 Fun]

I do feel a little bit that way...then again, everyone keeps telling me to drive in circles...



This has been done, nothing heard when either the diff lock or 4wd button are pushed.



I just did this. Drove around in tight circles several times, in both directions. Everything felt normal to me, and there was no noticeable dragging. I thought 4WD (at least in 4H) and AWD were the same thing though. What is the difference?



I'll have to wait until later today to do this test. Does it mean anything that I can't rotate the front driveshaft by hand, while it is parked with the engine off and all tires still on the ground? I can rotate my Tacoma's front driveshaft when it is in this same condition. I don't understand the difference between the two vehicles' 4WD systems. I thought the only difference was the T4R has the center diff lock, and the Tacoma has the rear diff lock.

And thanks for the additional clarification on the grinding while changing gears with the 4WD shifter.

From the information that I have gathered and someone correct if I am wrong, AWD mode allows power to be distributed to both axles differently which is usually used on snow covered or rainy roads, or hard packed dirt. Because it is not locked it does not create binding on hard surfaces. Essentially if one tire loses traction all power goes to that tire thus only have 1 wheel drive. Center lock or 4wd distributes power equally to both axles regardless of slippage which essentially makes your vehicle a true 2wd (or what most say when they put their vehicle in "4wd") because now one tire on each axle has to lose traction before your stuck. The rear axle isn't dependent on the front axle. If a tire loses traction in the rear your front axle will still get 50% of the power distributed to it, unlike AWD which wouldn't receive any.

A locking diff in the axle allows both tires on an axle to rotate the same so if you had one in the rear than you essentially have a true 3wd vehicle because regardless if one of your rear tires loses traction, both tires will rotate the same plus one wheel in the front axle. A true 4x4 would have two lockers, one in the front and and one in the rear axle with the transfer case distrusting power to both axles equally or "center diff lock" engaged.

You can't tell the difference from turning and making circles between 2wd and AWD because the power gets disturbed differently and does not create any binding. You can though if your "center diff" is locked which means its in 4wd. Only on a hard surface do you feel the binding in 4wd which is why it's not recommend to do often.

This is the basic understanding of how it works, different vehicles utilize different distribution scenarios for AWD though and that would be another discussion that doesn't need to go into. Again correct me if I'm wrong, but this is how I interpreted from what I've come across.

 

[concordcarlos]

Maybe I have even less of an understanding than I thought. I believe the 4WD shift only has three positions, from top to bottom: 4L --> N --> H.

The shifter is in the same position for 4H and 2H. So you're right, it's not like the two positions are 1/8" away from each other. They are the same exact position.



Does it also grind when going back into the "H" position from the "4L" position?

No,only when going into 4L.

 

[Andy in Pa]

I do feel a little bit that way...then again, everyone keeps telling me to drive in circles....

Lol... very true!!!

This has been done, nothing heard when either the diff lock or 4wd button are pushed..

Ok, that's bad. Something is not engaging/dis-engaging. Where did you buy this truck? Dealer or private person? My feeling is your going to need to take it to a Toyota dealer or mechanic to figure out whats happening.

I just did this. Drove around in tight circles several times, in both directions. Everything felt normal to me, and there was no noticeable dragging. I thought 4WD (at least in 4H) and AWD were the same thing though. What is the difference?.

Good... its not stuck in 4WD, which means its driveable on-road.
4WD and AWD are NOT the same.
4WD = 50/50 split of power from front to rear.
AWD = 60/40 split of power (or similar ratio, basically more power going to rear, less to front. If rear tires slip, front tires will provide traction.

I'll have to wait until later today to do this test. Does it mean anything that I can't rotate the front driveshaft by hand, while it is parked with the engine off and all tires still on the ground? I can rotate my Tacoma's front driveshaft when it is in this same condition. I don't understand the difference between the two vehicles' 4WD systems. I thought the only difference was the T4R has the center diff lock, and the Tacoma has the rear diff lock..

Not sure, I have not messed with mine to know if the front driveshaft turns freely until put into AWD mode. I can't be much help with understanding the differences between a Taco and a T4R 4WD system. Do you have manuals for both? Maybe use that as a reference?

And thanks for the additional clarification on the grinding while changing gears with the 4WD shifter.

No problem... I think you can drive it most anywhere, the only unknown is if its in 2WD or AWD. Maybe try to do some more digging on this site for answers, but I think your going to need a Toy mechanic/dealership figure it out from here though.

 

[ehuesman]

No more replies needed, truck is a fraud

Unfortunately, when I registered the truck on Toyota.com, the service history was displayed. There was record showing the truck was serviced last August, and the mileage at that time was 342,544 miles....and my odometer currently reads a little over 101,000! So now I am trying to go after the seller.

Thanks for everyone's time and input.