95 toyota t100 5 speed 4x4

[Layeredeye975]

4x4 ain't working on my 95 t100 I put it in 4 wheel drive and the light don't come on but u can hear it kick in and the front drive shaft locks and spins with the transfer case but the front wheels don't pull

 

[2ndGenToyotaFan]

You may have the "ADD" front differential. There is a mechanical disconnect on the drivers side of the front differential. It is vacuum actuated. Do some searching on how to diagnose this. It is a messy system that is prone to causing problems.

If you don't have the "ADD" front end then I would suspect the locking hubs next.

 

[Layeredeye975]

Yeah its automatic lock hubs and yeah I know I've been all over the vacuum system and its a pain

 

[Layeredeye975]

Cause

 

[Layeredeye975]

The 4x4 worked last year but like I said the 4x4 light don't come on now

 

[KLF]

There is a switch on the sliding cog in the front differential, if it's not sliding into place then that is why the light is not coming on.

 

[Layeredeye975]

Ok thanks

 

[pappy]

There is a switch on the sliding cog in the front differential, if it's not sliding into place then that is why the light is not coming on.

My knowledge of ADD is nil. So, you are saying on an ADD truck the 4WD light is triggered at the diff and not at the transfer case.

 

[cruiserdan]

There is an actuator on the front diff similar to a diff-lock actuator on an 80 (vacuum operated as opposed to electric however). It has a position switch on it.

 

[KLF]

There are actually 2 switches. One on the transfer, one on the front diff (like C-Dan confirmed). Both have to be closed in order for the 4WD light to turn on.

 

[Layeredeye975]

Ok that's good to know

 

[KliersLC]

The ADD actuator is notorious for failing. They are relatively easy to fix or replace though. I pulled mine and replaced with a pre ADD stub shaft anf housing and swapped in the manual locking hubs.

 

[Layeredeye975]

So how can u fix the actuator without buying a new where they are pricey

 

[KLF]

It's usually not the actuator, it's the VSV valves on the pass side inner fender.

 

[Layeredeye975]

Ok he vsv is sucking air but but not as hard. As if u take the vacuum hose of its self