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Discussion Starter #1
Hey guys,

To start with, I'm talking about an 03 Taco, 3.4L, with AT and auto hubs....

Last winter I needed to go into 4wd at an iced over street intersection, and normally you hit the button, the T case thinks about it for a minute, then it engages and you're off. You can do this while rolling too, but under a certain speed - it think 88 mph or you'll see some serious crap...

Anyway, that day I hit the button and a strange, high speed grinding noise happened. It's been happening ever since, unless I am at a complete stop.

Anyone heard this before? Any tips for me to start diagnosing this problem. Running a search for transfer case grinding is not very helpful!

Thanks all,

Bryan
 

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Discussion Starter #4
push button t case?

Probably need a new actuator on the tcase. common problem on the 4runner push button tcase, not sure if yours is the same.
Yes, it is a push button.

Is the actuator vacuum? Would I just replace that one part on the T case then?

Thanks
 

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Discussion Starter #6
So the problem is getting bigger... here's what I have found:
There are two actuators for ADD 4WD trucks, the first is on the back of the T-case and it's the 4WD actuator that transmits driveline power to the front diff - we'll refer to that one as the 4WD actuator.
The second is the ADD actuator and it sits on the passenger side of the front diff; this one locks the right axle to engage the front end when you are in 4WD - we'll call this one the ADD actuator.

Both have small motors with worm gears that turn other gears and make the magic happen. The motors are rather delicate and seem to have a rather short life honestly.

The other day I went to engage 4WD and it was slow to engage. I was barely rolling to lessen the T case grinding sound I experience, and so I hit the gas and heard something of a bang int he front end and no 4WD at all. I've confirmed that the 4WD actuator is working since it's icy outside. All you do is have someone else hit the button and give the truck gas on ice. If you see the front drive shaft spinning, then the 4WD actuator is working (although mine causes grinding if you are rolling). Have them hit the bottom again (to disengage the 4WD) and the front shaft will not turn while the rear tires spin on the ice.
So it seems that my front ADD actuator is not working. I'm planning to replace both and see if that corrects both the lack of 4WD as well as the grinding in the T Case. Updates to come....
 

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check the vacuum lines if yours has them. they have caused mine not to work once when they came unhooked. Also as a temp fix you can slide the sleeve in the jack shaft tube over to be engaged and block off the vacuum lines to bypass the motor.
 

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I don't mean to jack the thread but my 4wd in my 02 Tacoma seems to be having problems. I sometimes cant get it out of 4wd, and when its in it feels like something is dragging. My steering gets a little tough too. Thoughts? I just noticed it a few weeks ago. Its an 2002 3.4 manual. Its my plan to drain the front diff and transfer case this weekend and check the driveshaft. Any other thoughts would be great.
 

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Discussion Starter #10
check the vacuum lines if yours has them.
- Don't have them. There are vent tubes, but mine is all electric like Dick says:

Toyota uses a failure prone POS electric actuator on them, ...and they all suck.
- That sums it up, but if I can replace them and get good use out of them for another 11 years, eh, why not?

I sometimes cant get it out of 4wd
My research shows that this is an ADD actuator problem, but I don't know any other way to verify than testing the electrical. If the actuator motor is getting weak, then maybe that's all there is to it. It just isn't strong enough to move the fork. Read this and this. Good trouble shooting in those links...
 
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