[zipastro]

I have a 95 t100 and just noticed that 4wd will not engage(worked fine last sping). I located the vacuum lines on the acuator and firewall and they same to be intact with no cracks.

Here is the strange thing, while trouble shooting I reversed the lines on the acuator and then 4wd engaged as soon as I shifted into 4wd?

My first thought was a bad line so I switched them back to std on the actuator and reversed them at the electric switches, same thing instant on?


anyone have diagram for the system?

[KliersLC]

I am not exactly sure what your problem is from your description, but I hope these will help.



Dan

[zipastro]

Thanks, anyone know how the vac system works? Does it keed vac applied to each port at all times? Or only to activate

[KliersLC]

I would check for you, but I took the ADD out of my rig....

I'll take a look through the manual tho...

Try the tests above. They should be able to isolate the problem.

[tntoyota]

Originally Posted by KliersLC

I took the ADD out of my rig....

I'd have to say I did the same. WAY easier, shafts don't rotate all the time (sling grease, MPG slight loss, wear), simply find some Asins bolt them on. I pulled a vac on my actuator vac hose crimped it in my fingers and blocked the line and let go, works/ed like a charm!


FFT

[zipastro]

Turns out one of the vac solenoids is bad, $400 for new from Toyota.

[KliersLC]

That should be the same solenoid as on a mid 90s pickup, or maybe even a taco. I'd send you one of mine, but my pickup is on vacation in CA.....

See if you can pull it off and take it to a junkyard to compare.