Won't engage in 4 hi, But will in 4 low....

Okay guys I got a dosie here. First off quick intro I've been lurking around these forums fixing my 99 Tacoma 3.4l v6. I'm from the sunny Canada, British Columbia to be exact, where logging roads are aplenty and the mountain passes are high.

My issue to day has me stumped. I've been reading all about actuators and loose connections but in my mind these don't fit. Everyone else's 4x4 systems seem to have not worked at all. Mine does not work in 4 hi but does in 4 low.

When I put the transfer case in 4 hi the front axel is engaged but the front wheels spin freely when raised.

4 low is all good to go though.

From my understanding putting the truck into 4x4 automatically engages the electronic components, while switching from 4 high to low only affects your gear ratios.

Has anyone else had this problem?

Any suggestions on where to start would be greatly appreciated.

Cheers

Llama_Duck

 

It's not clear to me how you're testing. I'd suggest to put all 4 wheels up on jack stands, put it in 4 high, and put it in drive and see how many wheels are spinning. You should have at least one spinning in front and 1 in the rear.

 

I've tried this, neither of the front wheels spin in 4 hi, but one does spin in 4 low.

 

Do you have manual hubs?

 

Is the front driveshaft spinning in high?

 

I'm guessing you have the j shift variant? Vacuum or electric actuator?

 

If hes ADD, I'm wondering if something's wrong with the 4wd push button. It has a switch that auto engages 4wd when you put it in 4 Lo. That would explain why. Does the light on the dash for 4wd come on when you try to put it in 4Hi?

 

No they're ADD

Yes it does and yes it's j shift. There is no push button to go into 4wd. I think Vacuum Actuator because of the year.

It doesnt have a push button for 4wd and unfortunately the guy before me tried to wire in a switch but all he did was f*ck with the light on the dash so it never turns on

 

Wonder if something's wrong with the wiring...

 

Sounds like something is wrong with the wiring for the ADD. I'm not familiar with the vacuum setup but if it's electric, pins 2 and 6 should briefly see voltage when it's shifted into high.