Rear Diff E-Locker Question

I have used my rear diff locker regularly in the past, last time probably at the end of March. Never had any real engagement issues besides the normal lag. Today I was unable to get the rear diff locked. Tried all the normal tricks( into and out of drive, turning left and right, trying to break the rear end loose on dirt) and just had the flashing red light. Never got it to engage.

I can hear the relay clicking up front and if I shut the truck off in 4-Lo and turn the battery back to accessory, stand outside the truck and reach in to engage the rear locker, I can hear the actuator moving back there.

Any ideas?

Thank you,
Matt

 

Try slightly zigzagging your ground track slightly, that usually does the trick.

 

I will give that a try tomorrow. Thank you.

 

Gave that a try this morning with no luck. In the past it’s only taken 15 seconds at most.

I can hear the motor on the diff engaging just wondering if the small gear is not engaging or I have a bad switch?

I will try to jack the rear up this weekend and see if I can get it to engage by rotating the rear wheels.

 

Doesn't state you tried to backup; engage 4lo, engage locker, back up 10-15 feet.

 

Hi.

Yes, tried all the normal stuff. No luck.

 

Yeah it's possible the locker actuator is engaging but the position switch is bad, so you don't get a solid indicator light in the dash. However, it's one assembly to replace unless you want to open up the actuator casing.

Replacement actuator assembly is about four bills: https://www.rockauto.com/en/moreinfo.php?pk=12213425&cc=3353820&pt=50305&jsn=419

 

So no external switch on the rear diff housing?


I appreciate all the help.

 

I see you're in the NE...how old is your 4R?

 

5 years in July, Wool Waxed since day one.

On a side note, my front ADD died about a year ago from water intrusion, that thin rubber breather line had a tiny split on the nipple.

 

Jacked up the rear with 4 low engaged. Had my wife cycle the switch while rotating the rear wheels, gave a little tap with a mallet on the actuator as well....no luck. Diff stayed opened.

I can hear something going on in the actuator but it is not engaging.

 

^That suggests the actuator is receiving signal/power but not engaging, so replace the actuator.

6th gen owners can look forward to parking brake actuators doing the same thing after 5 years

 

Question on replacing the actuator if anyone knows. Remove old, lock rear diff manually with flat blade or pry bar. Make sure new actuator is indexed at 0-5 degrees.

Do I connect the electrical connection to the new actuator once installed with the diff lock switch in the engaged position? So then turning the key and applying power to the truck, press the diff lock button and that should disengage the diff?

Or does switch position on the overhead not matter if I have the diff locked manually which should activate the plunger style switch in the rear diff itself?