new to the 4runner forum. I just bought a 2003 sr5 and the 4h and 4l system will not engage.it just flashes. was told it could be the front differential sensor part # 84222-35070. also the locking rear does not work either. is the sensor part of the same system or something else?? any input on this subject will be great. it has 91,000 miles on it. any thing else I should look for while under the hood or preventive maintnance I should look for??
engaging 4x4 system
- Thread starter keith64
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Sporin
New member
Only the 2009 Trail edition has a locking rear diff. you are probably thinking of the Locking Center Diff. That won't lock unless it's already in 4WD.
I'll let someone else more versed in the intricacies talk about what might be wrong, but I wanted to help clarify that info for you.
BlackWorksInc
New member
Have someone take a hammer or preferably a mallet and TAP on the actuator/transfer case firmly while trying to shift into 4WD. They get stuck from lack of use and usually you can work them loose this way.
If you search "Stuck 4WD Actuator" on the forum you should find a healthy amount of solutions/threads on the issue.
If you search "Stuck 4WD Actuator" on the forum you should find a healthy amount of solutions/threads on the issue.
yes, your are correct with locking rear. it is the V S C OFF switch , center differential lock switch . could it be the 4wd actuator sensor that I mentioned in my first post or it may be the fuse. I will check the fuses today. are there any low rear diff. oil sensors that could cause the system not to work. thank you keith
9494runner
New member
You mean always....:typing:
Martinjmpr
New member
Wait...
Before you start hammering anything, how are you trying to engage the 4wd?
What, exactly, are you doing? Particularly in the case of 4lo there is a very specific method of doing this, and most people do it wrong the first time because they haven't taken the time to read the manual or even the little card that's on the visor.
I'm presuming the vehicle is now in 2hi. To engage 4hi, you should be moving with the transmission in gear (I know you can put it in 4hi in P or N but my experience has been that it will go in more quickly if you are moving.) With the vehicle driving slowly forward, turn the dial from 2h to 4h. Both the green and yellow 4wd diagrams on the dash should be flashing. They should flash for a few seconds and then the yellow one should go out and the green one should go solid, not flashing. If that is happening, you are in 4hi. If you get a constant flashing of both yellow and green, try stopping, shifting into reverse and going back a short distance, then shift back to D and go forward again.
To go into 4lo, you must first come to a COMPLETE STOP. Then you must put the transmission in NEUTRAL. Not park, not Drive, not Reverse. NEUTRAL. Once the vehicle is stopped and the transmission is in neutral, turn the dial from 4h to 4l. You should hear/feel the t-case shifting and the green 4lo light on the dash will come on.
Going from 4lo to 4hi is the reverse of the above procedure, i.e. you have to come to a COMPLETE STOP and put the transmission in NEUTRAL.
If the transmission is not in neutral when you are trying to shift from 4h to 4l or 4l to 4h, you will just hear a loud angry beeping noise.
If none of the above work, then I would do the tapping-on-the-actuator bit. But I always say before you start messing around under the truck make sure you are activating the 4wd system correctly because otherwise it could be that you're simply doing something out of sequence and knowing the right way to activate 4wd can save you a lot of time and a lot of headaches.
Before you start hammering anything, how are you trying to engage the 4wd?
What, exactly, are you doing? Particularly in the case of 4lo there is a very specific method of doing this, and most people do it wrong the first time because they haven't taken the time to read the manual or even the little card that's on the visor.
I'm presuming the vehicle is now in 2hi. To engage 4hi, you should be moving with the transmission in gear (I know you can put it in 4hi in P or N but my experience has been that it will go in more quickly if you are moving.) With the vehicle driving slowly forward, turn the dial from 2h to 4h. Both the green and yellow 4wd diagrams on the dash should be flashing. They should flash for a few seconds and then the yellow one should go out and the green one should go solid, not flashing. If that is happening, you are in 4hi. If you get a constant flashing of both yellow and green, try stopping, shifting into reverse and going back a short distance, then shift back to D and go forward again.
To go into 4lo, you must first come to a COMPLETE STOP. Then you must put the transmission in NEUTRAL. Not park, not Drive, not Reverse. NEUTRAL. Once the vehicle is stopped and the transmission is in neutral, turn the dial from 4h to 4l. You should hear/feel the t-case shifting and the green 4lo light on the dash will come on.
Going from 4lo to 4hi is the reverse of the above procedure, i.e. you have to come to a COMPLETE STOP and put the transmission in NEUTRAL.
If the transmission is not in neutral when you are trying to shift from 4h to 4l or 4l to 4h, you will just hear a loud angry beeping noise.
If none of the above work, then I would do the tapping-on-the-actuator bit. But I always say before you start messing around under the truck make sure you are activating the 4wd system correctly because otherwise it could be that you're simply doing something out of sequence and knowing the right way to activate 4wd can save you a lot of time and a lot of headaches.
The OP describes the symptoms I had when I first tried 4WD on our used 4Runner (Yes, I bought a used 4wd truck and didn't test the 4wd first, and I'm still beating myself up over that). After reading all these threads on stuck actuators I got underneath with engine off while someone moved the switch back and forth. I could hear the actuators in the center diff trying to work but heard nothing from the front actuator. I bought a replacement front actuator ($310) and just connected it to the front actuator electrical harness. Repeated above test and everything 'worked' and the dash showed it going in to 4HI, 4LO, and diff lock. I drained the front diff fluid, removed the actuator (a little tight in there but was able to reach the 4 bolts) and took it apart. The electric motor had seized. I actually fixed and tested it, soldered the connections based on another post, and reinstalled it. I later confirmed it was working when on a friend's hoist and all tires were off the ground. We now drive the truck each month in 4wd. I still have that new front actuator if the original fails again.
My advice to the OP is to listen with the engine off (key on, obviously) and try to determine which actuator is not working and go from there.
My advice to the OP is to listen with the engine off (key on, obviously) and try to determine which actuator is not working and go from there.
