4wd Not Engaging

Been a lurking member for a while, lots of great stuff on here. I have a problem with my 4wd not engaging. Its a 2001 auto tranny with the j shifter. Last year I had to have the flywheel replaced and after that the 4wd light did not come on again, although I took it back and they rechecked all of the connections and it was good, but 4wd DID work. I have used 4wd an uncountable amount of times since then. However, yesterday I got into a tight spot and put it in and nothing. I did have to replace the battery last week and already checked the 20 amp fuse under the dash and all is good. Just don't know where to look next. Thanks!

 

Anybody? I pulled off the skid plates to get to the axle and 4wd actuator yesterday and am going to start checking wires and all today. Just don't know where to start throwing parts at it. thanks

 

I'd jack up the front end, turn the wheels or axles and look/listen for anything unusual. There isn't a clean cut way to diagnose this issue, you just need to get under there and get after it.

 

I traced and tracked wires yesterday and could not see anyting broken or out of sort. I'll put her on stands in a bit. I figure the 4wd actuator may be a good place to start replacing given the age of the truck.

 

Did you try turning the axles manually with your hands? I'd just follow the torque and see where it's not carrying through and start diagnosing there.

 

I have a brand new 4x4 switch sitting here if you need it....when my 4wd went out I bought it from Toyota...turns out my ADD had gone out.

PM me if intrested

 

Thanks, but I've got a new actuator coming.

 

Did you check the integrity of the vacuum line going to the actuator? "If the ADD system does not properly engage the front drive mechanism, the first items to check are the vacuum supply hoses. " Via this link http://www.off-road.com/trucks-4x4/tech/the-automatic-disconnecting-differential-system-19259.html

 

It was my understanding that my 01 is an electric actuator without any vacuum lines. Upon inspection I could not see an inlet for any vacuum.

 

New actuator in and running right now. Thanks

 

I found out today that my 4wd is not working on the truck I recently bought. 2001 double cab, auto like the OP's. My bro in law came over and checked it out. After running through a few checks he thinks it's the actuator. Transfer case and everything seems to be working fine. My diff light does not come on either. Does this sound like the actuator to you? If so, is it a pricey fix? How bad of a DIY?

 

I took it to the dealer to have them look it over and do an inspection. He said the computer wouldn't tell him anything since check engine light isn't on. Anyway, regarding the 4wd. Mechanic said he believed it to be the ADD actuator. The dealership said it would be $705 to replace. $380 for part plus labor. I looked online and ordered the actuator for $170 and will install myself.