Hi guys,
I installed the e-locker on my 1998 4runner recently. I had a complete parts truck with 4.56 factory gearing, so I swapped the front diff also when doing the e-locker retrofit.


I went wheeling yesterday for the first time since the swap, and after a couple of moderate obstacles I noticed that my front wheels are not getting any power.


I did a quick check over (it was cold and dark) on the trail, didn't notice anything unusual. Went home. Truck drove perfectly fine in RWD.


Now onto the weird part.. The 4WD light on the dash lights up when t-case is shifted to 4WD. The vacuum at the ADD actuator is strong and switching as it should (when the 4wd J-Shifter is moved between RWD and 4WD.) T-case is also working properly (front drive shaft starts spinning when shifted to 4WD).
The usual suspect in this case would be blown CV's, but im 99% sure they are fine also. 4WD worked fine before I swapped the front diff, and I surely didn't do anything hard enough on the trail to snap both CV's at the same time. Only running 32's, 4cyl engine, open front diff. Each front wheel spins freely when the truck is in "4WD".


My only other guess would be broken spider gears in the diff, but i'm doubting that also. For one thing, there is absolutely no unusual noises / resistance coming from the diff when either wheel is spun (with 4wd light on), or when the driveshaft is spinning. Secondly, the parts truck that I got the diff from was owned by a grandma, and has never been off-roaded. Oil in it looked good. The 4wd worked as per dash light (but I never checked if the wheels were getting power though).


What could it be?! It feels like the ADD is not engaging, but it should. The light comes on, the vacuum is there and the actuator is good (I actually used my original one from my truck, which was confirmed working).


Another weird (to me anyway) thing that I noticed is that the 4WD light comes on (or off) INSTANTLY, as soon as the t-case is shifted between RWD and 4WD, even without the engine running! It will do this indefinitely, as long as the vacuum lines are connected. If one is disconnected momentarily, the light will no longer come on until the engine is restarted.




Does anyone have any ideas? Thanks in advance!

 

Do you think it could be in your hubs?

 

Solid hubs on a 98 4Runner. Unless he's done some rare Taco parts swapping.

It really sounds like something is fishy with that ADD diff. I thought (could be wrong) that the 4WD light won't come on and stay on until the ADD engages and a limit switch in there gets closed.

Maybe it's as simple as that limit switch being stuck 'on'?

 

Thanks for reading guys.



I figured out what the problem was today.



I had a very strong suspicion that the issue was ADD related. Luckily I still had my old diff/add mechanism lying around, so I took it apart and started brainstorming. I removed the actuator and looked inside... There is a sleeve that should be moved left/right to unlock/lock the passenger side CV axle. There is a groove in this sleeve for the fork on the actuator that moves it. Turns out if the sleeve is moved all the way to the left (it will move further beyond unlocked position) the actuator will bolt up and the fork will miss the groove. The fork will still have full travel range, thus activating the limit switch which activates the 4wd dash light, but the locking sleeve will never move with it, being stuck in unlocked position.



Sure enough, I took out my ADD actuator and that's exactly what the problem was. The sleeve must've moved out of the way when I was installing the actuator.. I reinstalled the actuator properly and my problem is gone.



Hopefully this post will help someone if they run into a similar issue.

 

Excellent troubleshooting.



Andreas