Jeremy11

Ok... Last week my 4WD was working fine. Took my truck out tonight and all of a sudden my dash 4WD light is not turning on and my 4WD itself is not engaging. When i put it into 4H shortly after you can hear a click in the dash. My 4L is working. But not in 4WD. Im going to check my gear oil tomorrow. Any other suggestions?

This is in a 1990 4Runner 3.0 V6 automatic with auto-locking hubs


Any Help is Appreciated!! THANKS!

drew303

Check the vaccum lines at the front differential. Wouldnt surprise me if you had a vac leak. The auto-hub system ... doesnt actually have anything to do with the hubs as they're basically spooled.. Theirs a vaccum driven mechanism on the driver side of the differential that basically engages the axles.

Engage the 4wd and check around bet you find a leak

drew303

Then start thinking about converting to manual hubs. Theres threads on here that detail how to do it. Warn hubs are cheap and will work just fine, hell i got Aisin and Warn sets just sitting here, bout ready to chuck em. It's a cheap and not so hard modification

annoyingrob

Check that the 4wd shift linkage itself didn't actually come off. The A340H auto transmission (which you might have) uses an electric solenoid for low range, and a manual shift linkage rod for 4wd. Also, if the transmission fluid is low, or too cold, it may not shift into 4wd.

Jeremy11

So how would i go about checking for the vacuum leak.

Where would i find this. Or what does it look like?

RobD

http://www.off-road.com/trucks4x4/ar....jsp?id=399612

jrobertson4runnner

would you be willing to sell one of those sets of hubs? if so i might be interested.

Jeremy11

i cheked my vacuum lines atthe top and there was no vacuum. i checked the lines at my front differential and there was no vacuum either. is there some sort of hose diagram where the hoses should go on the passenger side of the TB that are numbered 1-6.

NO Money

hey drew befor you throw the hubs away any chance of you mailing them to me.. i need a set for a 94 ifs 4runner... hook a 4runner up!!!!!!!!!!!

annoyingrob

Look underneath the truck, from what I can remember, there's a little metal rod that goes from the shifter, back to a little pivot, then forward to the side of the transmission.

2DoorRunner

Im pretty sure i have the same problem. Either that, or im just paranoid.

Jeremy11

I followed this diagram for my ADD vacuum lines and it fixed everything.
Except i dont know where the hose goes for the first insert in the first cluster of 3 at the top.

Logan R. Daugherty

I know this thread is old, but i have an automatic 1993 4runner 4wd and my 4wd either seems weak or is not engaging..i have a small leak coming from tcase but only shows itself when i engaged 4wd. Any ideas? Im at a loss and just think i need a new tcase.

scope103

Oh, I dunno, you could start by reading how the original poster fixed his problem. At least check those items.

Why?

Logan R. Daugherty

im thinking t case because the front drive shaft still locks in but wont pull me up a hill