After sitting for several months while I was deployed, our 4Runner's transfer case actuator was sticking giving me a pair of flashing lights (the green 4wd light and the yellow center differential lock light). After I trawled the forums looking for ideas here's what I came up with:
- Engaging and disengaging the 4wd repeatedly is a good first step. In my case however, no amount of engage/disengage, rocking, coasting, forward reverse was getting any results.
- Crawling under the car with a buddy in the driver's seat changing the 4wd switch is a good way to see/ hear what the actuator is doing. On my 2008, it turns out there is an inspection port that you can unscrew and view a pointer dial that gives you an idea of what's going on inside the actuator.
- While under the car, grab the front and rear driveshafts and rotate them while the buddy cycles the switch. You can feel if the actuator is binding up / and whether the differential is engaging the front shaft. If it is binding, turning both the driveshafts slightly may help it engage.
- My motor was really frozen so I had to take another step. I removed the actuator bottom plate and was able to rock the motor coupling with a small screwdriver. I marked the gear's position and moved the motor shaft about 1 revolution forward, then back about 3-4 times. The motor felt less bound up after a couple of turns. (Take care opening the case bottom as there are gears that will come off their shafts and rest on the bottom plate. Just keep the bottom plate level as you lower it from the actuator and the gears will stay put. I had to loosen the three actuator attachment bolts and remove the one transfer case guard bolt that was in the way of lowering the bottom plate of the actuator.)
- I then put it back together and had my buddy cycle the 4wd switch again. I could see from the inspection dial that it was moving about 90 degrees at first, engaging the front shaft but still beeping. After a couple of cycles (and a twist of the rear shaft) it went all the way to 4wd hi. A couple more cycles and then to 4wd low. It seems to be shifting much more smoothly now and the lights glow steady when in 4 Hi/Lo, and when I lock the differential. The inspection dial shows it traveling about 240 degrees to the locked mark.
The actuator looked brand-new inside and had lube on the gears. I didn't lubricate the motors at this point since they seem to be much happier now.
BTW, the breather hose on the actuator case was problematic for several of the owners who posted problems. Toyota used a hose that has serrated flare on the end so it will slip over the breather fitting easily. I think these serrations crack over time resulting in a loose fit / falling off the fitting leaving the actuator exposed to water (some of the pictures of failed actuators revealed rust and crud over its components, clearly water had seeped in and made a real mess). I clipped off the end 1/4 inch of the hose to remove the flared end (which looked close to failure) and re-attached it for a nice snug fit.
Transfer Case Actuator
View attachment 104587
Inspection port / pointer dial
View attachment 104589
Inside Actuator to rotate motor coupling to free it up
View attachment 104590
Breather hose flared end removed
View attachment 104591
Thanks to all who have posted, I found it well documented how important it is to "use it or lose it" with these actuators so I'll be sure to use them weekly.
