4Hi & 4Lo Actuator Questions

Hello everyone,

I would like to start off by saying I have searched hi and lo (pun intended) before asking for help on this one. I am familiar for the most part with how the 4x4 engages and disengages. At the moment if I put the truck into 4hi all I get is the typical flashing and it never engages. With the truck off and the key in the on position (hadn't tried for a few months) I heard what sounded like something binding metal wise and now I have a permanent humming coming from the 4x4 actuator on the TC. Next step would be to open up the actuator however the screws are completely shot. They have rusted so bad that unfortunately I do not think they will ever turn due to the lack of a Philips head profile to bite to.

2 questions....

1) Has anyone dealt with the rusted screws and if so how did you get them out? I did see one guy mention he just chiseled off the heads and then removed the assembly once the motor gears no longer had contact with the 4hi and 4 lo forks and then replaced with a new actuator.

2) Although all I hear is consistent humming from the TC could it be that it has worked and the actuator on the front diff has failed? If so, is there a rebuild process for it or a way to confirm it is doing its job.

Thank you guys!

 

I’m in the same situation! I just attempted to open mine up last week and they’re complete rusted shut, hardly identifiable… and my truck only has 70k miles. I hate the North East

 

The ADD goes first. If successful, then it’s the TC’s turn to move. If not successful, then the TC doesn’t do shit.

 

I managed to get the TC Actuator housing opened after drilling out the heads of the screws and found it to be immaculate inside. I bench tested the motor and it works just fine. Plugged the assembly back in without entering the housing to test if it would operate when putting it into 4HI and nothing happens, same with when I switch it back to 2wd. The 4hi light will stay flashing regardless of the selection until I turn the truck off and start it again.

Can anyone else confirm the ADD goes first? I have always seen on the documentation that the TC is the first step in the process.

Thanks for any and all help!

 

Looks like you are right. TC first then ADD.
I re-watched this video and the guy does say TC first.
https://www.youtube.com/watch?v=47m7QAPrpsI&list=PL1dqFNXG1wm1kg1Jkthb5vL433OjYohM8&index=2&t=560s

 

Thank you! Next step would be checking voltages coming from the Module harness to TC correct? I believe I should see 12-14v on TM1 either TM2 when selecting 4HI, correct?

 

With the plug disconnected, yes, you should see 10-14v.

 

Success that I now have power and when the motor is plugged into the harness it will switch to the 4wd position. That being said the 4hi light flashes. Checked the front actuator and I don't hear a peep from it when trying to engage. Probably just going to replace it and flush the front diff.

 

Did you check the voltages on the ADD plug?

 

I did not yet. The last time I used my 4x4 it had a tough time coming out and ended in a very loud bang in the front diff. I ordered the parts to have on hand but ill be sure to double check before I start.