no 4wd

[3bears]

tonight I went for a drive, put it in 4wd high and no light or indicator came on and it did not feel like it was in 4wd. I stomped on it in gravel and only the rears kicked rocks.I have no check engine lights either.
ive only owned this for about 6 weeks and this is only the third time I have tried to use the 4wd and it has worked in the past
however one day my son drove it , and for fun he tried it and he said it did not work

where do I start ?



2000 v6 sr5

 

[TheDurk]

This is where you start:

VSV’s/ADD
Don't guess at it, troubleshoot! Start at the twin VSV's (Vacuum Switching Valves) on the driver fender wall. There are two long vacuum hoses that come up from the diff, one goes to each VSV. Check to see that one of the two hose nipples on the VSV’s has vacuum (engine running, 4WD NOT engaged. If no vacuum either side, check the check valve going to the intake manifold and look for loose hoses or a hole in the reservoir. If there is vacuum going to one hose, then put it in 4WD. See if the vacuum switches to the other hose. If it does, and no 4WD, problem is the diff actuator or the line to the diff. If it does not, then just switch the hoses and you should go into 4WD. This confirms diff is okay. (Mark the hoses first so you know which belongs where!)

OK, switch them back. Then use a test light to see if electrical signal from the TC also switches sides of the VSV. If it does not, problem is the TC, the switch on the TC, or the TC actuator, or its wiring back to the button (last two for non-J shift only). If it does, but the vacuum does not, the problem is the VSV itself.

I start troubleshooting at the VSV's because you can figure out where the trouble is without having to climb under the truck. [None of this applies to '01-'02 which have an electric actuator.]

 

[NWFLBowhunter]

Crawl under and check for wires unhooked from the top of the transfer case/transmission area. When I bought mine I had similar issues And got it cheap because the 4wheel wouldn't work. After doing the above test, it turned out to be the wiring harness has not been hooked back up after a clutch install.

 

[3bears]

This is where you start:

excellent

 

[3bears]

Crawl under and check for wires unhooked from the top of the transfer case/transmission area. When I bought mine I had similar issues And got it cheap because the 4wheel wouldn't work. After doing the above test, it turned out to be the wiring harness has not been hooked back up after a clutch install.

thanks

 

[3bears]

This is where you start:

can you direct me back to the original thread that had this information

seems I need to go deeper

thanks

josh

 

[3bears]

I can only find one hose from diff...the other large hose going to the box is the fuel evap hose I believe because it smells like gas.

on the one side that has a big hose going to diff, the other is going to the airfilter housing

on the other side is a hose going to to the intake manifold to a valve. I have suction coming from the intake, but nothing on the out side of check valve

if I take that large hose form intake and go to the hose going directly to the diff...nothing happens

I guess Ill crawl under and see if ther eis another hose and where it goes

 

[3bears]

k
now I feel stupid

so I tried backing it up etc, no 4 wheel drive
put it in forward....nothing. put the ramps under it, went to pull onto it, and my light came on
drove around the farm turning it off and on, works

don't get it

 

[3bears]

is there a relay right near shifters ( automatic with jshifter 4wd) cause now I have a clicking sound every time I shift in and out of 4 wheel and the sound is coming fomr just below the shifters
and all is working

 

[3bears]

maybe the vacuum on the diff was stuck, and going direct form intake to the hose to solenoid unstuck it ????

 

[TheDurk]

can you direct me back to the original thread that had this information

seems I need to go deeper

thanks

josh

Sorry, I wrote it several years ago after diagnosing my own rig (broken wire on T-Case sender) and have posted it dozens of times. The best thread on this to go deeper is on YotaTech; it goes 20 pages:

4WD won't disengage on 99 4Runner LTD - YotaTech Forums

 

[3bears]

thanks for your help
its working

 

[TheDurk]

k
now I feel stupid

so I tried backing it up etc, no 4 wheel drive
put it in forward....nothing. put the ramps under it, went to pull onto it, and my light came on
drove around the farm turning it off and on, works

don't get it

Sounds to me like your check valve was stuck, and effing with it opened it up. Swap it, 'cuz it will probably gunk up again. Any generic check valve from NAPA for $4 will work fine.

No relay on the J-shift T-case--it's all mechanical. Maybe something on the slush box, I don't have one so I can't say.

 

[3bears]

Sounds to me like your check valve was stuck, and effing with it opened it up. Swap it, 'cuz it will probably gunk up again. Any generic check valve from NAPA for $4 will work fine.

No relay on the J-shift T-case--it's all mechanical. Maybe something on the slush box, I don't have one so I can't say.

I guess I did not see a check valve anyplace, at least one that would look like I could place with a generic. the only things that looked like check valves came off the intake manifold hose, and it had an electrical connection to it

but thanks again for your help

 

[3bears]

after 4 days off playing in the woods on forest service and old logging roads, my 4wd gave me no issues
so what ever I did seems to have fixed it

 

[3bears]

soooooooo :mad2:
my 4wd is not working again....and of course just when I needed it as it was snowing

symptoms, no lights on dash, no 4wd not 4H or 4L

with help from TheDurk, I found I can switch hoses and get the 4wd to work
the hoses to the front diff.
what I have found is that I have power all the time at the brown plug ( 2 wheel drive) but when switch to 4 wheel drive the power and vacuum does not switch to the blue valve, nor does the light on the dash come on.
Thedurk thinks it might be the switches on the transfer case

however, is one switch a Low switch and one a high switch, ? why would both be dead unless one feeds the other with power

I checked and rechecked the fuse and its ok.
but if the wire had gone bad or disconnected from the back fo the fuse box, would I still have power to the 2wd valve
im calling it a 2wd valve as its the one that is active in 2wd

 

[3bears]

Its alive .....
a loose wire plug connection at transfer case
was cheking things out....again...and climbed underneath and checked the plugs at the transfer case, hit one and heard that "click". I said...I know what that sound is.....slid out from under, fired it up...and its alive

Special thanks to The Durk, RCastle for offering to come help, and Tracy at Lithia Toyota for his offer to help

next week when I get to my sons, ill put it up on ramps so I can reach better, pull the plugs, clean them and put back together

crossing my fingers