Ok I have a 93 4runner V6 automatic 4x4, the front diff is not engaging and no 4x4 light. We hear the click under that dash when shifting to 4x4, I checked the vacuum lines and did find the red actuator on top of the fender to not pass vacuum but if I bypass that and get vacuum to both lines at the diff it still does not engage. The transfer case does engage and you can see bat driveshaft’s get torch on them, just for some reason the diff in not working, I pulled electrical connector on the on the diff and confirmed it does get power when you shift into 4x4, I did a search on the forum and found some helpful tips to try and chance this down but now I am stumped. Does anyone have any ideas?

 

The vacuum actuator on the front of the front diff is probably fubarred. Easy to remove and diagnose once removed. Could be a cheap part from the junkyard or a good time to switch to manual hubs.

 

I am not against manual hubs, my plan is to SAS this down the road when funds are more available so I hate to much money on this setup now. This is not DD just a trail rig. Is there are good way to just lock the sleeves in place, that are controlled by the vacuum? There are some days it may get driven to the trail, but most of the time I plane to trailer it when I can.

 

My actuator is was so screwed up that I just manually put the sleeve/fork over to the locked side and looped the vacuum line together. Its been stuck in that position without any problem for 2 years, about 25K miles... So you might try that. Others have had success with some kind of hose clamp, keeping the actuator fork from returning to the unlock position.

 

Cool I think I will just do that, the vacuum seems like a liabilaty on the trail to me anyway.

Thanks!