Another 4WD broken thread

[chattyT4R]

Recently got some snow in Colorado, so it was 4wd time.

Went to a parking lot with some friends and decided to mess around with some donuts and such. Drove pretty aggressively.

Ended up getting stuck a couple times, and used 4wd to get out, shifting in and out for a minute or two and it worked well and smooth, even went to 4lo to lock the diff and do a circle spin.

However, now the issue is the entire 4wd system seems to be broken. I am familiar with 4wd issues on these cars, and had to replace the entire transfer case last time it broke.

BTW - 2000 limited with m/m shifter and rear diff lock

I watched this video - YouTube
and noticed he had somewhat of the same issue

Symptoms - locked into 4wd, light blinking no matter what position shifter/button is in. I can go into 4low and can feel the low gearing when driving.

However, unlike the video, my light is constantly blinking. As mentioned before, I have had 4wd issues before but not like this one. I can move the transfer case lever in and out of 2hi and 4hiL, push the button, whatever but the light doesn't change, specifically what bothers me is there is no hesitation like the one in the video, just consistent blinking. I tested the switch that I believe is the 4wd position indicator? not sure the name, but the one where the connector is by the cat, on the passenger side.

If anyone has any suggestions or info that could help. I haven't tried jumping the actuator yet but will soon and see what happens.

I am currently driving around just with the vacuum lines switched on the front VSV thing, so the wheels are at least not binding

I was at one point able to get the 4wd light to stay solid by messing with the sensors (plugging unplugging and physically completing the circuit) and not sure what did it but it stayed solid when the lever was in 4hiL and then would begin to blink when I shifted back out. I went back out recently to try and get it to shift into 2wd since the light seemed to be working, but it is once again stuck into just blinking, regardless of shifter input.

I am not sure where to go - I feel if it was one of the sensors not working shifting would as least cause the light to hesitate and change, or I would be able to detect some change but there is no sign that shifting currently has any effect. I tested the switch as I said, and when I shifted into 4wd and 2wd, there was a change in continuity so I believe that is still working.

Is this possibly a bad 4wd computer? Something else? Any suggestions welcome.

 

[BrianSD_42]

In future don't put the locker on then try to do donuts.

I am familiar with 4wd issues on these cars, and had to replace the entire transfer case last time it broke.

How did it break the last time before you had to replace the whole transfer case, what caused that?

In terms of reliability these 4wd systems are Rock solid when used properly. I don't have MM but still, everything is working great after countless 4wd trips and 260K miles.

One thing that was recommended to me the one time years ago when my 4wd was acting strange is to open the 4Runner year user manual (for real) and properly go through the exact steps from going 2WD to 4WD HI, test it, then return to 2WD. Key is to follow the exact exact steps for your model year.
.

 

[chattyT4R]

UPDATE: Did some more messing around, trying to figure out what is going on. I tested all the switches/sensors I could get to, front one was a little iffy but after some cleaning it works fine now. 4WD position switch and the two by the actuator both work.

I am able to engage the front diff by switching the vacuum lines, and the tires will either spin in opposite directions or just one will spin (hand spinning) so I am guessing that the front vacuum actuator is fine

The front driveshaft is locked, as in I can't spin it by hand

I am getting a bit worried now because I have a feeling there might be internal damage with the T-case or the actuator is broken, neither option is going to be a cheap or easy repair.

Right now, I have the front wheels locked by the diff (when one is turned the other wheel spins the opposite way) and the front driveshaft is locked (does not spin by hand) however when driving on the snow I am pretty obviously in 2WD. So is it possible that the transfer case just isn't engaged to the front driveshaft and that's why there is no power being sent to the front?

I am hoping it's not something like the front diff being stripped, but I think I would be able to hear noise from the front if it was spinning around.

Going to try and jumper the actuator on the transfer case, see if that works and I am praying it does.

Got stuck twice today, once in my driveway and once in a snowpile, could have easily gotten out of both wild 4WD

If anyone has any experience with symptoms like there or has any ideas what is wrong please let me know!

 

[chattyT4R]

In future don't put the locker on then try to do donuts.



How did it break the last time before you had to replace the whole transfer case, what caused that?

In terms of reliability these 4wd systems are Rock solid when used properly. I don't have MM but still, everything is working great after countless 4wd trips and 260K miles.

One thing that was recommended to me the one time years ago when my 4wd was acting strange is to open the 4Runner year user manual (for real) and properly go through the exact steps from going 2WD to 4WD HI, test it, then return to 2WD. Key is to follow the exact exact steps for your model year.
.

The last time it broke was because the actuator went bad, and I swapped in the new one because the car was new to me and that is what the shop recommended

I know locking the diff for donuts probably isn't the best idea, but it was on plenty of snow so I didn't see any risks of binding, and for the record it worked pretty well

Also, I did try the exact steps, and I have tried about every method that other users have recommended. There was one point in a snowy parking lot that I got the light to stay solid and then stay off by just kinda rocking back in forth in and out of 4WD, but it didn't last long.

Drove home from that parking lot in 2Hi then when I got to my street that was unplowed I tried switching into 4WD but it just started flashing the light again and has been since.

The weird problem I see is that shifting in and out with the lever, button and whatever doesn't seem to have an effect on the 4WD computer, judging from the light blinking not being altered. I did check the 4WD position switch, and it's working properly. Maybe there is a problem with the wiring? But I don't know I haven't really heard of issues like that.

 

[chattyT4R]

So basically I realized after thinking about it that I think the problem is that the center diff is not locking, if anyone has knowledge on why everything else seems to be working but this doesn't.

Also if it even possible for the front driveshaft to become locked (not hand turnable) and yet the center diff not to be locked so the front driveshaft isn't getting power.

 

[spartacus]

Here is a pretty good thread might help.
Won't go into 4 wheel drive

 

[Tinigunner11]

Dude! reading this is crazy, Im up by Fort Collins and I am having the EXACT, and I mean EXACT, same issue with my 2000 limited. I have tested everything that you stated above, bought and tried a new 4wd computer, a new Ecu for the truck, installed a new transfer case. and I still haven't found the issue. I can get it to go in to 4wd by switching the hoses on the VSV. I can jumper the actuator but the 4wd Ecu will switch it back right after I turn the truck on. Ive tested and replaced switches, jumpered both actuators on both transfer cases and both work. But I can't figure out what the heck is going on.

Mine worked fine until I swapped transmissions, once I hooked up my old transfer case to the new(used) trans nothing worked. I've been studying the writing diagrams and have all the 4wd FSM pages if you need them, I've been studying them like crazy. Here is some of the links that I have been looking at: 27. VF3AM TRANSFER - Google Drive

Possible 5 speed swap input appreciated - Page 3 - Toyota 4Runner Forum - Largest 4Runner Forum

1999 Limited 4WD issues (multi-mode transfer case)

4WD won't disengage on 99 4Runner LTD

4WD lights are flashing...HELP!

this link the guy fixed his by replacing the vsv. This will be my next step.
4wd flashes in 2wd.


Have you checked you vsv on the fender well? does the blue one have power but the brown was doesn't? If you need help I'm close-ish and dealing with the same issue. And if you need a good multi mode transfer case, or 4wd Ecu I've got one of each handy

 

[Tinigunner11]

Here is also a link to a 2000 FSM:

2000 4Runner FSM - Printable - Google Drive

 

[TheDurk]

The last time it broke was because the actuator went bad, and I swapped in the new one because the car was new to me and that is what the shop recommended

I know locking the diff for donuts probably isn't the best idea, but it was on plenty of snow so I didn't see any risks of binding, and for the record it worked pretty well

Also, I did try the exact steps, and I have tried about every method that other users have recommended. There was one point in a snowy parking lot that I got the light to stay solid and then stay off by just kinda rocking back in forth in and out of 4WD, but it didn't last long.

Drove home from that parking lot in 2Hi then when I got to my street that was unplowed I tried switching into 4WD but it just started flashing the light again and has been since.

The weird problem I see is that shifting in and out with the lever, button and whatever doesn't seem to have an effect on the 4WD computer, judging from the light blinking not being altered. I did check the 4WD position switch, and it's working properly. Maybe there is a problem with the wiring? But I don't know I haven't really heard of issues like that.

Oh it happens. A few years ago the mice got to the wires on top of the trans on mine. More recently the wire to the 4WD position switch broke right at the connector. It's a very thin wire, and it stayed right where it was, but no longer passed current. It was hard to spot, but I knew I had a wiring fail between the relay and the switch.

As to the shaft, it needs to be locked at both the TC and the diff. Just one is not good enough. In your case, I'd put it up on front and rear stands and idle it in 4wd. Then you can see if the front D/S is turning or not, and know for sure if the problem is in the TC or the diff.

 

[chattyT4R]

Dude! reading this is crazy, Im up by Fort Collins and I am having the EXACT, and I mean EXACT, same issue with my 2000 limited. I have tested everything that you stated above, bought and tried a new 4wd computer, a new Ecu for the truck, installed a new transfer case. and I still haven't found the issue. I can get it to go in to 4wd by switching the hoses on the VSV. I can jumper the actuator but the 4wd Ecu will switch it back right after I turn the truck on. Ive tested and replaced switches, jumpered both actuators on both transfer cases and both work. But I can't figure out what the heck is going on.

Mine worked fine until I swapped transmissions, once I hooked up my old transfer case to the new(used) trans nothing worked. I've been studying the writing diagrams and have all the 4wd FSM pages if you need them, I've been studying them like crazy. Here is some of the links that I have been looking at: 27. VF3AM TRANSFER - Google Drive

Possible 5 speed swap input appreciated - Page 3 - Toyota 4Runner Forum - Largest 4Runner Forum

1999 Limited 4WD issues (multi-mode transfer case)

4WD won't disengage on 99 4Runner LTD

4WD lights are flashing...HELP!

this link the guy fixed his by replacing the vsv. This will be my next step.
4wd flashes in 2wd.


Have you checked you vsv on the fender well? does the blue one have power but the brown was doesn't? If you need help I'm close-ish and dealing with the same issue. And if you need a good multi mode transfer case, or 4wd Ecu I've got one of each handy

Good to know I am not the only one with this issue right now haha. I was actually up in Foco a couple days ago too (not in my car). I'll check into those links you posted thanks.

When you jumped the transfer case actuator, what exactly did you use to do it? I am going to try that next even though I am pretty sure it's working but it doesn't hurt to check, although I am a bit iffy on electrically jumping it so I just want to be safe.

I did check the vsv's, and it doesn't switch sides right when I shift the lever but I know that both are working and they will switch occasionally, but that hasn't solved my issue yet.

Let me know if you solve your issue!

 

[chattyT4R]

Oh it happens. A few years ago the mice got to the wires on top of the trans on mine. More recently the wire to the 4WD position switch broke right at the connector. It's a very thin wire, and it stayed right where it was, but no longer passed current. It was hard to spot, but I knew I had a wiring fail between the relay and the switch.

As to the shaft, it needs to be locked at both the TC and the diff. Just one is not good enough. In your case, I'd put it up on front and rear stands and idle it in 4wd. Then you can see if the front D/S is turning or not, and know for sure if the problem is in the TC or the diff.

Hmm interesting, that could be the issue. Do you know any way to check the wiring and see if there is a break in the wiring? I know where the plug is, and I checked the switch by having someone shift the lever in the car and testing the continuity w a multimeter, it checks out.

I got a chance to put it on a lift today, and when in drive it does spin the front wheels

HOWEVER, I am 100% sure that real "power" is not being sent to the front, as I was also able to test it on some ice and found that my back wheels will spin but the front's will not get power. Seems like the "center diff" is running like an open diff (if that's a thing for these) and it's not like a locked diff if that helps

 

[chattyT4R]

Dude! reading this is crazy, Im up by Fort Collins and I am having the EXACT, and I mean EXACT, same issue with my 2000 limited. I have tested everything that you stated above, bought and tried a new 4wd computer, a new Ecu for the truck, installed a new transfer case. and I still haven't found the issue. I can get it to go in to 4wd by switching the hoses on the VSV. I can jumper the actuator but the 4wd Ecu will switch it back right after I turn the truck on. Ive tested and replaced switches, jumpered both actuators on both transfer cases and both work. But I can't figure out what the heck is going on.

Mine worked fine until I swapped transmissions, once I hooked up my old transfer case to the new(used) trans nothing worked. I've been studying the writing diagrams and have all the 4wd FSM pages if you need them, I've been studying them like crazy. Here is some of the links that I have been looking at: 27. VF3AM TRANSFER - Google Drive

Possible 5 speed swap input appreciated - Page 3 - Toyota 4Runner Forum - Largest 4Runner Forum

1999 Limited 4WD issues (multi-mode transfer case)

4WD won't disengage on 99 4Runner LTD

4WD lights are flashing...HELP!

this link the guy fixed his by replacing the vsv. This will be my next step.
4wd flashes in 2wd.


Have you checked you vsv on the fender well? does the blue one have power but the brown was doesn't? If you need help I'm close-ish and dealing with the same issue. And if you need a good multi mode transfer case, or 4wd Ecu I've got one of each handy

https://drive.google.com/drive/folders/1B-tNyCa4dwijcRQDv8pL1cUgjMdncW0A

I think that this one is a good place to look as far as testing the actuator switch. It'll be interesting to see if any of the steps aren't working, but it doesn't really say much as far as what to do if they don't work (or maybe I'm just missing something)

 

[TheDurk]

Hmm interesting, that could be the issue. Do you know any way to check the wiring and see if there is a break in the wiring? I know where the plug is, and I checked the switch by having someone shift the lever in the car and testing the continuity w a multimeter, it checks out.

I got a chance to put it on a lift today, and when in drive it does spin the front wheels

HOWEVER, I am 100% sure that real "power" is not being sent to the front, as I was also able to test it on some ice and found that my back wheels will spin but the front's will not get power. Seems like the "center diff" is running like an open diff (if that's a thing for these) and it's not like a locked diff if that helps

Well, I used backprobes on my multi-meter to diagnose my wiring issue from the 4wd relay. I knew my position switch was responding at the TC, but the wire pair at the relay was always open. (5-speeds have relays, not ECUs.)

As far as the center diff issue, that's off my reservation. I don't do slushboxes.

But, are you sure you are not in multi-mode AWD? Because that's how that would work. Rear wheels would just spin. You need to be in H4L or L4L, but I assume you know that.

 

[chattyT4R]

Well, I used backprobes on my multi-meter to diagnose my wiring issue from the 4wd relay. I knew my position switch was responding at the TC, but the wire pair at the relay was always open. (5-speeds have relays, not ECUs.)

As far as the center diff issue, that's off my reservation. I don't do slushboxes.

But, are you sure you are not in multi-mode AWD? Because that's how that would work. Rear wheels would just spin. You need to be in H4L or L4L, but I assume you know that.

Yeah it seems kinda like it might be multimode. Maybe something is not locking into 4L and it's in multimode limbo or something. Do you know where the difference comes from in multimode? Is it the front diff being unlocked or is it something in the T-case?

Also, if I try to test the 4wd computer plug, it's a big plug in with a bunch of wires that I have seen before but basically would it would to just test it by unplugging it and poking into the holes with a multimeter, or does it need to be like plugged in and somehow find a way to test it that way.

And lastly what's the slushbox thing haha

Btw I have seen you in almost every 4wd thread that I have looked at and I am glad you are getting on to mine, your experience and knowledge is valued

Edit: just adding more thoughts I am having.

Like I asked above, where does awd for these come from. I cannot 100% confirm that the actuator is working yet, so maybe it is the actuator? If you or anyone else could provide like a reasonably detailed explanation on how to test it that would be great.

I am thinking just use a battery charger on 12v 2amp but then how do I run wires for power to the actuator?

Thanks again, sorry for all these long posts but personally when I try to find info on issues I like as many details as possible.

 

[phattyduck]

Like I asked above, where does awd for these come from. I cannot 100% confirm that the actuator is working yet, so maybe it is the actuator?

At first blush, I would guess something is up with the actuator... whether the motor or the position switches are bad - who knows?

The transfer case on the multi-mode 4Runners has a differential in it that can lock, and it is 'open' when unlocked (no limited slip capabilities). I would still expect a front wheel to get power and spin in some situations if you are in 4H-unlocked (AWD) though.

The same actuator engages the center differential (2WD to 4WD-unlocked) as locks the center differential (true 4WD). If it is stuck in-between modes *or* one of the position sensing switches for the actuator (all on the same plug on the transfer case - the motor/actuator on the back) is bad, it would act like what you are seeing.

Moving the shift lever from 2H/4H-u to 4H-l is still only operating a switch inside the transfer case (not a mechanical link) and uses the actuator to shift. The shift from high range to low range is mechanical, which is why that is still working for you.

That's about as far as I can go with diagnosis from here though...

-Charlie

 

[chattyT4R]

At first blush, I would guess something is up with the actuator... whether the motor or the position switches are bad - who knows?

The transfer case on the multi-mode 4Runners has a differential in it that can lock, and it is 'open' when unlocked (no limited slip capabilities). I would still expect a front wheel to get power and spin in some situations if you are in 4H-unlocked (AWD) though.

The same actuator engages the center differential (2WD to 4WD-unlocked) as locks the center differential (true 4WD). If it is stuck in-between modes *or* one of the position sensing switches for the actuator (all on the same plug on the transfer case - the motor/actuator on the back) is bad, it would act like what you are seeing.

Moving the shift lever from 2H/4H-u to 4H-l is still only operating a switch inside the transfer case (not a mechanical link) and uses the actuator to shift. The shift from high range to low range is mechanical, which is why that is still working for you.

That's about as far as I can go with diagnosis from here though...

-Charlie

Thanks for the info. Today I jumped the rear actuator which was probably the sketchiest thing I have done while laying in snow, and the motor works. When I yurned the car back on though (engine running) it kinda freaked out and sounded like it was spinning crazy whenever I tried to put it in gear. That happened a couple times then it stopped doing that, and now it is in full locked 4wd, spinning the front wheels with power.

I can get the 4wd light to stay solid all around when I use wires to fake the front switch being pressed in, but it still won’t shift at all. I cleaned the front sensor and confirmed it was indeed working, and even swapped it with the one on the tcase that has the same connector, both work.

I am going to check the front actuator later to make sure that is working, but it’s still being weird. When I had the 4wd light solid then tried to shift, it would wait a second then just start blinking but as far as I could tell it wasn’t actually attempting to shift.

Could it be a bad 4wd computer? All the electrical wires seem to be intact and working just something isn’t sending or receiving a signal. Going to trouble shoot more and come back with updates

 

[chattyT4R]

It seems like the 4wd actuator can shift, it’s just not because something isn’t telling it to. Both the switches on the actuator seems to be functioning fine , anything else to check?

 

[chattyT4R]

Here are all the things I have checked and are operating - let me know if there is anything you think I am missing

-2 Actuator positions switches
-4WD shifter position switch
-VSV's - checked for resistance and operation
-Front diff operation - unlocks and locks
-Front switch on front diff
-Acuator - works when jumped - full range from locked to unlocked

Everything seems to be working, but for some reason the light just doesn't stop blinking, and nothing will "shift" without me physically jumping it or switching the vacuum valves. I am pretty lost here folks

One thing I did notice that was odd is that the two sensors on the actuator seems really sensitive. They allow continuity when just barely pressed. Like pressing a button on your phone distance, but the one on the front diff doesn't open unless you press it about a quarter to half inch maybe. I tried swapping it with the one one the actuator as mentioned above, but that didn't help either.

Heeelllllpppp

 

[phattyduck]

Pull the 4WD computer and open it up... look for burned components or leaking capacitors.

I normally wouldn't suggest that the computer is bad, but you are getting there. Might be worth checking prices on ebay for one...

There still is a chance of something broken inside the transfer case since you mentioned some weird sounds when you put it in gear when you may have been in an odd spot for the actuator.

Keep going!

-Charlie

 

[chattyT4R]

Pull the 4WD computer and open it up... look for burned components or leaking capacitors.

I normally wouldn't suggest that the computer is bad, but you are getting there. Might be worth checking prices on ebay for one...

There still is a chance of something broken inside the transfer case since you mentioned some weird sounds when you put it in gear when you may have been in an odd spot for the actuator.

Keep going!

-Charlie

When I jumped the actuator again, it went in and out and both times did not make the weird noise again

Is there a way to clean inside the actuator? I was thining of opening the little panel kinda on the top of it and spraying electric parts cleaner or WD-40 in there and then letting it dry out or something. I know taking the actuator on and off is a pain in the ass and I would like to avoid that considering that right now it seems to be working fine, but I imagine cleaning wouldn’t hurt