So I engaged and disengaged the 4Lo a few times and then pressed the Center Diff lock button. I got the flashing center diff light and no engagement. So I tried to go back to 4HI. The 4Lo light went out, but it stayed in 4Lo, and the center diff light stayed flashing. I had actually had this problem once before but it reset after a restart and I was able to go back to 4HI. But this time, no dice. Ugh!!
I tried everything; drove around in 4low to warm everything up, trying all the gear combos, driving in circles, backwards and forwards, I actually drove a couple miles in 4lo and had the vehicle running for at least 30 minutes, multiple restarts, disconnecting battery, recharged battery, disconnecting and cleaning the actuator harnesses on the Tcase itself. I even ordered and replaced the main Tcase ground wire because it looked a little frayed. No luck.
Unfortunately the actuators can not be removed without removing the Tcase and splitting it open. At least, thats what the FSM says.
So I have to give credit for this fix to the great TROLLHOLE! Marshall Shepherd of Trollhole's Cruisers in Simpsonville, SC. Many of you know him, he's a great guy and does great work. Ive worked with him for years and he's worked on many of my Cruisers. I called and asked him if he knew of any tricks to fix this. Asked if I tapped on it with a mallet, and I hadn't and also suggested I set a heater up underneath the truck to warm it all up. (He also mentioned he had freed up the center diff on an FJ Cruiser by getting it in an off camber position and twisting it up a little and hitting the switch.)
So I jacked up the left rear and right front tire to tweak it all a little bit. I removed the balancer/dampener thingy, the heat shield and the skid plate/Tcase exoskeleton and disconnected the harness. Set up the space heater pointing right at the actuator assembly for a couple hours. I tapped on it with a rubber mallet several times, and finally took a heat gun to it.
Then I crossed my fingers and pressed the start button to ACC without starting it. Not sure why I didnt start it all the way, maybe because I was still on jack stands, but thats what I did and VOILA! No flashing diff light and 4Lo light back ON! I dropped it down, took it out and switched to 4Hi and bingo! It worked.
I guess if that center diff actuator gets jammed, it sends a fault code to the 4WD ECU and prevents any switching between Hi-Lo.
The actuators themselves are plastic gears inside a plastic housing all caked in grease. It reminds me of the infamous power seat motors and gears on the 80 series. Over time, that grease congeals and gets really sticky, almost like glue. I think cold temperature just makes this problem worse. Maybe its best to just leave that heat shield off, especially if you live in a colder climate.
If you are ever stuck in 4Lo, the first thing I would do is remove the four bolts for the heat shield, that bolts onto the exoskeleton. The actuator assembly sits in between the two exhaust pipes where they come together, so if you were in a jam, maybe the heat from the exhaust would be enough to soften the grease inside the actuator and free it up.
I also learned from the FSM that the temp sensor inside the actuator will alter the amount of current to the actuator depending on the temp. Evidently, it still wasnt enough juice to free it up with that sticky grease inside, it needed some extra heat.
Anyway, maybe this keeps someone from getting stuck in 4Lo miles from home, or keeps them from having to take it in to the dealer for a hefty repair bill.
Pic of Tcase with balancer/dampener removed, the heat shield removed, skid plate/exoskeleton in place, and the black plastic center diff actuator and Hi-Lo range actuator in the middle.....
I tried everything; drove around in 4low to warm everything up, trying all the gear combos, driving in circles, backwards and forwards, I actually drove a couple miles in 4lo and had the vehicle running for at least 30 minutes, multiple restarts, disconnecting battery, recharged battery, disconnecting and cleaning the actuator harnesses on the Tcase itself. I even ordered and replaced the main Tcase ground wire because it looked a little frayed. No luck.
Unfortunately the actuators can not be removed without removing the Tcase and splitting it open. At least, thats what the FSM says.
So I have to give credit for this fix to the great TROLLHOLE! Marshall Shepherd of Trollhole's Cruisers in Simpsonville, SC. Many of you know him, he's a great guy and does great work. Ive worked with him for years and he's worked on many of my Cruisers. I called and asked him if he knew of any tricks to fix this. Asked if I tapped on it with a mallet, and I hadn't and also suggested I set a heater up underneath the truck to warm it all up. (He also mentioned he had freed up the center diff on an FJ Cruiser by getting it in an off camber position and twisting it up a little and hitting the switch.)
So I jacked up the left rear and right front tire to tweak it all a little bit. I removed the balancer/dampener thingy, the heat shield and the skid plate/Tcase exoskeleton and disconnected the harness. Set up the space heater pointing right at the actuator assembly for a couple hours. I tapped on it with a rubber mallet several times, and finally took a heat gun to it.
Then I crossed my fingers and pressed the start button to ACC without starting it. Not sure why I didnt start it all the way, maybe because I was still on jack stands, but thats what I did and VOILA! No flashing diff light and 4Lo light back ON! I dropped it down, took it out and switched to 4Hi and bingo! It worked.
I guess if that center diff actuator gets jammed, it sends a fault code to the 4WD ECU and prevents any switching between Hi-Lo.
The actuators themselves are plastic gears inside a plastic housing all caked in grease. It reminds me of the infamous power seat motors and gears on the 80 series. Over time, that grease congeals and gets really sticky, almost like glue. I think cold temperature just makes this problem worse. Maybe its best to just leave that heat shield off, especially if you live in a colder climate.
If you are ever stuck in 4Lo, the first thing I would do is remove the four bolts for the heat shield, that bolts onto the exoskeleton. The actuator assembly sits in between the two exhaust pipes where they come together, so if you were in a jam, maybe the heat from the exhaust would be enough to soften the grease inside the actuator and free it up.
I also learned from the FSM that the temp sensor inside the actuator will alter the amount of current to the actuator depending on the temp. Evidently, it still wasnt enough juice to free it up with that sticky grease inside, it needed some extra heat.
Anyway, maybe this keeps someone from getting stuck in 4Lo miles from home, or keeps them from having to take it in to the dealer for a hefty repair bill.
Pic of Tcase with balancer/dampener removed, the heat shield removed, skid plate/exoskeleton in place, and the black plastic center diff actuator and Hi-Lo range actuator in the middle.....