4WD not engaging

[Leonard 1979]

Hello all. New to the page. 2017 RAM 6.4 HEMI 4WD not engaging while engine is running. I have the dial. 4WD LOCK flashes on the dash when dialed to 4wd and never engages. I replaced the front axle actuator and transfer case motor and still the same problem. Pulled up the carpet and no corrosion on the module. Now when the truck is off and the key is in the run position the 4WD will engage. It will also engage if I dial it within the first 5 seconds of starting my truck. The disengage works fine and will disengage whenever I want. It just will not engage under normal operations. Fluid level looks fine in the transfer case. This has me puzzled. Thank you.

 

[dunney]

Do you get the SERV 4WD alarm? Dows it have any codes? I’m just curious as I’m having a similar issue with an older truck.

Could be knob/switch, TPIM, ECM.
I wish I had better suggestions but I’m looking for answers myself!

 

[62Blazer]

When the engine is running and the 4wd light flashes, do you have it in gear (drive) and sitting there with the brakes on? Have you tried putting in gear and letting it roll forward or reverse?

 

[Dean2]

Hello all. New to the page. 2017 RAM 6.4 HEMI 4WD not engaging while engine is running. I have the dial. 4WD LOCK flashes on the dash when dialed to 4wd and never engages. I replaced the front axle actuator and transfer case motor and still the same problem. Pulled up the carpet and no corrosion on the module. Now when the truck is off and the key is in the run position the 4WD will engage. It will also engage if I dial it within the first 5 seconds of starting my truck. The disengage works fine and will disengage whenever I want. It just will not engage under normal operations. Fluid level looks fine in the transfer case. This has me puzzled. Thank you.

Read your owners manual. There is a list of things that must be true for 4Hi to engage and a separate list to engage 4LO. Start there then come back and tell us if there is still a problem.

 

[markabby]

Read your owners manual. There is a list of things that must be true for 4Hi to engage and a separate list to engage 4LO. Start there then come back and tell us if there is still a problem.

read the owners manual??

 

[Dean2]

read the owners manual??

Ya I know. Radical advice in this day and age.

 

[turkeybird56]

Ya I know. Radical advice in this day and age.

Wat U get for common sense approach. Not think any of our leaders either side possess any.

 

[dunney]

When the engine is running and the 4wd light flashes, do you have it in gear (drive) and sitting there with the brakes on? Have you tried putting in gear and letting it roll forward or reverse?

I tried getting it to go in drive, neutral, and reverse , both running and off, key on/off. I think it’s something electric, like the TPIM or ECM. I reseated all the fuses in the fuse block and that got me into 4WD the first time. The second time it failed last night I just had to manually keep resetting the individual codes.