4wd Wont Engage

For those interested, a few years back I had this issue. What worked for me was cycling the switch back and forth in rapid succession. After a minute or so of cycling the switch, it finally popped.

Also, I left my truck for 7mo untouched, and it shifted into 4hi and lo with no issues.
 
c_mack9 said:
When it's in 4hi with the center diff unlocked, should the center diff light blink and the VSC light be on? Everything is mechanically working, we just don't know what these lights are doing?
Click to expand...

Don't know if you ever got an answer to your question, but here it is:

In 4wd with the center diff UNLOCKED (i.e., OPEN), the only light that is lit up on the dash should be the green 4wd light (the one that looks like a schematic of the two axles and wheels.) It should be solid and not blinking.

When you LOCK the center diff, both the green and the yellow 4wd schematic will blink briefly and then the green one should go out and the yellow one (with the "X" in the place of the transfer case) should light up solidly. In addition, the ABS and VSC lights should also be on, solid, as the center diff lock disables these features.
 
Thank you but mine is all fixed up now. They replaced the actuators, and 4wd in hi and lo both worked but hte lights were flashing in 4hi open center diff. Turns out the front diff was busted and needed to be replaced. So the front actuator, transfer case actuator, and front diff has all been replaced. It costs a fortune, but we just got a fresh snow dump and it's AWESOME!
 
I did this repair recently on my 06 4.0 based on scw1991's posts. Yes you can get to this from the front of the truck after you remove the skid plates. It's a tight fit and you'll need to get creative with your socket wrenches.

My symptoms were the blinking 4WD and diff lock lights on the dash when trying to engage 4Hi. I'd have to cycle the ignition to get the lights to quit flashing. Obviously no 4Lo either as the former must happen first. Further troubleshooting with the help of my kid confirmed that with engine off and truck in N, when trying to engage 4Hi I could hear motors buzzing in the transfer case but nothing happening at the front actuator.

I drained the front diff fluid (make sure you can loosen the fill bolt first). Then I jacked up the front end and unplugged the electrical connector and vacuum line from the actuator. 4 bolts later and the thing was off. There's a frame crossmember right there but it did fit (barely). I then took it apart and sure enough the motor had siezed but was otherwise very clean inside. A couple drops of gun oil and it was spinning fine. While apart I also soldered the motor leads. After reassembling the actuator (it only goes back together one way) I didn't install it but plugged it back in under the truck (left it hanging by the connector). We did the engine off test and lo and behold it 'went' into 4Hi. I held my breath and tried 4Lo and it also worked (as did the diff lock). Woohoo!

Then I practiced reinstalling this which is the tough part. You need to make sure the diff collar is pushed to the correct side (you'll understand this when you see inside the diff housing) and it obviously goes in at an angle. I'm not sure but I don't think it will go on without the arm properly fitting into the collar, there's just not enough room otherwise. When I had my procedure figured out (mainly holding my tongue right) I dabbed some gasket sealant on and put it on. There are two alignment nibs, so when it's on at least the bolt holes line up.

Before refilling the diff fluid I tested everything and it still worked. I could feel it engage. This was quite a relieving feeling.
 
mb66 said:
I did this repair recently on my 06 4.0 based on scw1991's posts. Yes you can get to this from the front of the truck after you remove the skid plates. It's a tight fit and you'll need to get creative with your socket wrenches.

My symptoms were the blinking 4WD and diff lock lights on the dash when trying to engage 4Hi. I'd have to cycle the ignition to get the lights to quit flashing. Obviously no 4Lo either as the former must happen first. Further troubleshooting with the help of my kid confirmed that with engine off and truck in N, when trying to engage 4Hi I could hear motors buzzing in the transfer case but nothing happening at the front actuator.

I drained the front diff fluid (make sure you can loosen the fill bolt first). Then I jacked up the front end and unplugged the electrical connector and vacuum line from the actuator. 4 bolts later and the thing was off. There's a frame crossmember right there but it did fit (barely). I then took it apart and sure enough the motor had siezed but was otherwise very clean inside. A couple drops of gun oil and it was spinning fine. While apart I also soldered the motor leads. After reassembling the actuator (it only goes back together one way) I didn't install it but plugged it back in under the truck (left it hanging by the connector). We did the engine off test and lo and behold it 'went' into 4Hi. I held my breath and tried 4Lo and it also worked (as did the diff lock). Woohoo!

Then I practiced reinstalling this which is the tough part. You need to make sure the diff collar is pushed to the correct side (you'll understand this when you see inside the diff housing) and it obviously goes in at an angle. I'm not sure but I don't think it will go on without the arm properly fitting into the collar, there's just not enough room otherwise. When I had my procedure figured out (mainly holding my tongue right) I dabbed some gasket sealant on and put it on. There are two alignment nibs, so when it's on at least the bolt holes line up.

Before refilling the diff fluid I tested everything and it still worked. I could feel it engage. This was quite a relieving feeling.
Click to expand...



do you absolutely have to drain the differential fluid?
 
4WD not engaged and light does not lid up on dash

I had the same problem with my '98 LTD with E-locker. Preliminary test show that at "Park" 4W HI pressed, the transfer case actuator engage but not the front ADD. Further, diagnosis, with good vacuum source @ 20in, I discovered there is only one vacuum present at the actuator the other has none. I checked the vacuum line from the solenoid to the actuator, it's good. I unplugged both of the solenoids and with ignition key on, I found that one has power (brown solenoid) while the other solenoid (blue) does NOT have power with the "4WD" pressed.

Any suggestions where I should look for, beside trace the wire without power.
Keep in mine the 20 am fuse in the fuse box is good.

Thanks in advance.

Dave
 
I am working on a friends 2006 4Runner. When you try to put in in 4H, it blinks/beeps and never engages. I layed underneath and could not hear either the front ADD or the t-case motor engaging. I removed the front ADD and opened it up. It's clean and the gears/motor move freely. I connected a new one and as soon as the key was turned on, it moved to the 2H location. I put the old unit in the 4H location and plugged it back in and it moved to the 2H location. I'm out of ideas, I tried tapping on the t-case motor with no luck. Before I button this all back up, I'd appreciate any other suggestions. Thanks-Jason
 
I soldered the terminals in the ADD and reinstalled it. I'm waiting on the sealant to setup before adding oil back in the diff. I've crawled under, spun the front driveshaft while the selector was in 4H, still nothing but beeping/blinking. According to the diagnostic manual, the system engages the tcase before the ADD so I'm leaning towards that. I don't have time to mess with that this weekend and probably won't since it looks like the tcase has to come out. I was hoping to get this fixed for her before this ice storm hit :confused:
 
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