I have a 2002 4Runner and my 4wd light is flashing like a Christmas tree all the time. I had someone replace the front differential and it sheared the ring and pinion twice. (Now they will not do anything more to fix it).

What happened the last time was I got stuck in some snow and shifted it into 4hi and it sounded like a war was breaking out, then no 4wd and flashing 4wd light. The lo gearing still goes into effect when it is put into 4lo, but the front wheels do not engage. When I drive, I hear a slight tapping noise that sounds like it is coming from the front.

Does anyone have any ideas, what it is, or what I should check?

 

Maybe your t-case grenaded. Start there with checking fluid, (i.e. drain it and check for metal shavings), then look at putting the front end up on jack stands and seeing if you can turn the front wheels with the front shaft taken loose from the case.

 

If I drain it, I assume I am going to need to have new fluid on hand? This is all new to me so I don't want to screw something up even worse than it already is

 

Yes, you are gonna need to refill it...

 

sounds like whoever worked on your front end doesn't know what they were doing...I would get your money back from them and go somewhere else to get it fixed.

 

There's likely a problem with the ADD system(front axle), not with the transfer case.
https://www.yotatech.com/forums/f2/4...er-ltd-131201/

If you'd searched/googled "4WD light flashing" you'd have probably stumbled upon the right thread fairly easily.