CARspec had the opportunity to diagnose and repair a 2007 4Runner recently that wouldn't engage 4WD high or depression – the shift indicator would but blink and the car remained rear-wheel/2WD.  Hither are our notes on the diagnostics and the repair:

Toyota provides petty documentation and diagnostic aid when it comes to their temporary 4WD systems.  The 4WD module has no self-diagnostics and the repair manual is little help in the way of diagnosing transfer case actuator/front differential automatic disconnecting systems.  The wiring diagrams for the systems also don't signal when the monitoring switches (which track the internal location of the actuators) should exist open or closed.  Getting a skilful diagnosis on a failed actuator, either at the transfer or the forepart differential, is difficult.

After confirming the harness continuity from the 4WD module to the transfer actuator, the 2/4WD select switch, and checking all ability and grounds for the system (including some calorie-free taps of the hammer on the transfer actuator), the actuator itself was condemned as the root failure of the 4WD arrangement.  Hither'due south the actuator installed on the back of the transfer:

Transfer Case Actuator

Transfer Instance Actuator

Replacing the actuator, which houses both control motors and all the switches, is a complicated procedure if you've never tackled it earlier.  Information technology requires transfer case removal and partial disassembly.  Here'south what it looks similar opened upwardly, actuator still installed:

Transfer Case Open

Transfer Instance Open

The to a higher place is the transfer case open with the rear gear cluster installed.  Highlighted is the high/low select gear as well as the dog teeth that engages the eye differential lock.  The above is pictured afterward the new actuator was installed in the 4WD loftier position (the actuator itself includes the rods that are attached to each select fork pictured).  A sharp eyed technician will likewise note that the actuator shaft clips aren't installed – they were after the photograph was taken (there are three full on this transfer).

TOYOTA SHIPS THE ACTUATORS IN 4WD High POSITION.  MOVING THE ACTUATOR SHIFT RODS MANUALLY Whatsoever AMOUNT Will MISTIME THE NEW ACTUATOR, NECESSITATING A 2d NEW ACTUATOR.  DO Not MOVE THE ACTUATOR SHIFT RODS.  Information technology is OK to move the select forks and gears to get everything to line up, simply don't move the rods less y'all destroy the actuator and y'all'll have to buy another one.

Transfer Center Diff Lock

Transfer Heart Diff Lock

The leftmost gear sleeve in the above photo moves to the left when actuated to engage depression gear, rightward to engage high hear.  The rightmost sleeve in the photograph moves one step right to engine 4WD, and some other stride to the right to engage the center differential lock (two steps back left puts the vehicle dorsum into 2WD).  The to a higher place is currently in 4WD high.  Here's a closeup of the lockout shaft that prevents gear clash every bit well:

Transfer Closeup

Transfer Closeup

Noted are the hidden detent assurance that engine the lockout shaft.  They are minor and pill shaped and are inside the highlighted Fifty-shaped catches.

After the new actuator was installed and the FIPG gasket was allowed to sit overnight, the transfer example was filled with gear lube and returned to service, now with functioning 4WD High/Low and center differential lock.

CARspec is one of the few independent shops that offers transfer case repair and rebuilding on belatedly model Toyota and Lexus models, and one of the few shops in the Minneapolis area that has the expertise to diagnose Toyota and Lexus 4WD issues exterior of the dealership.  As Minnesota's independent Toyota, Lexus and Scion repair specialist we pride ourselves both our fast turnaround, expertise and quality that is unmatched in the manufacture.

If you have 4WD problems or questions, don't hesitate to phone call united states at (952)426-4798 today!