1990 Toyota Pickup. I just put new manual hubs (was automatic) on my truck and the 4 wheel drive still isn't working. How can i get the 4x4 working again?

 

did you do anything with the diff? you have to somehow engage the front diff, with vacuum and properly working add, or something mechanical like a hose clamp. do a search on how to convert add to manual

 

All i did was replace the old automatic hubs with manaul ones.

 

if your 4x4 wasnt working before then it wont work now. you need to either bypass the automatic disconnect in the diff or make it work correctly again. try seaching on google, i found a good article about it but didnt save it

 

You didn't have Automatic Hubs. You had/have Automatic Differential Disconnect. There's nothing more yo the hubs than just a plate to keep CV axles fixed onto the spindle. Your front differential has a separation on the drivers side inner axle with a sleeve that joins the two ends via vacuum actuator. Those actuators like to not work over time. Or there's a vacuum leak. Or electrical problem.

 

should i buy some new actuators?

 

I wouldnt. you can mechanically lock the disconnect. have you tried searching the forum?

 

when you put the hubs on ... did you put them on while there were in the free position??

 

i think the best question is did your 4wd work before you started?

 

yes, i did

 

no, the 4 wheel drive didnt work before i started

 

did you try looking up how to defeat the system on google?

http://www.4x4wire.com/toyota/tech/add/

 

how with that help me?

 

why doesnt the 4wd work?? what is it doing??

 

it allows you to bypass the vacuum actuator and makes it work basically the same way as a truck that came equipped with manual hubs... which i assume is what you want since you installed manual hubs

 

i dont know. its seems like the front diff isnt kicking in

 

ok. ill have to try it

 

Is your 4WD light turning on?
If it is turning on then your front diff is engaging and you need to set both hubs to "lock"
If the light is not coming on you have a problem with your ADD system (most likely a bad Vac line or Vac lines to the VSS actuators put on backwards (They're color coded))

 

My light does not go on. So it must be one of the vaccum lines? Maybe

 

if you are adding manual hubs, then you are most likely trying to bypass the ADD system - otherwise why do it at all?

if this is the case you need to do as the ADD removal process states, and permanently lock the ADD mechanism to the engaged position. i did mine with a hose clamp. all you need to do is pop the cover off, slide the geared sleeve over the stub shaft to the engaged position. when the sleeve is engaged, there is a ~1/2" of shaft exposed where the slide mechanism is attached - just enough room for a hose clamp around the shaft. once installed, it is literally impossible for the sleeve to slide back unless the hose clamp self destructs. as for the vacuum system - plug it off. done.

if your light doesn't come on, it's probably vacuum related. my truck wasn't ADD, but I installed a 4.88 ADD diff - so I can't help there. read the swap guide, your answer should be in there. at the least it will let you know what vac lines to look at - or just trace them up from diff to engine compartment and look at your vac diagram under hood/FSM