A.D.D issues?

I am looking at a truck that the seller says will not shift into four-wheel-drive unless you turn the truck off select four high and then turn it back on. He saying ADD. Does this sound legitimate?

 

His truck has attention deficit disorder?

 

The front diff actuator

 

So if I replace the actuator all together it should fix it?

 

Typically these are the symptoms of the front Diff actuator yes. Not a garenteed fix, but they typically get water inside and fail.

Also, the motor is not soldered onto the leads, it's kind of press fit. So eventually the leads don't make good contact anymore. You can pull the actuator out, open it up, resold er the leads, and try that before spending the money on a new one.

 

Awesome. Just wanted to make sure that worst case I could replace it and know that it would fix it

 

Going to look at it today so I will see. What should I expect to see

 

There are other things it could be. 4wd computer failed, limit switches on the transfer case failed, bent axle tube, the add collar sticking for whatever reason, etc

 

The truck does have 250,000 miles so I think what you said about not being soldered could be a likely cause

 

Does the transfer case cycle when you flip the switch? The add will not Cy Le until the transfer case is finished

 

I am going to look at the truck today. Should I expect hear the transfer case shift into 4hi? Or how do I know if the transfer case is cycling?

 

My last truck was a Prerunner so I know nothing about the 4x4's

 

Yeah try this. Don't start the truck, just turn the key to battery. Put the truck in 4wd and you should hear the transfer case shift underneath you. After that finishes the front Diff actuator cycles. Can't really hear that one since it's small and far away. You can have someone else flip the switch while you lay under the front and hear it that way.

 

So if the transfer case shifts no problem but the actuator doesn't engage the front end then the actuator is the culprit?

 

Most likely. The front Diff won't shift until the limit switch in the transfer case is hit so there is a small chance it could be the limit switch.

But most likely the front actuator. They fail all the time in these trucks.

 

Ok thanks.