Zuke76
08-10-2009, 09:48 AM
When I shift into 4H and 4L the dash light does not come on and I do not "feel" the front wheels pulling. Its worked fine about 2 months ago. Since then I have had the front shocks replaced by local mechanic. Also I have changed the plugs and cleaned the TB. In changing the plugs and cleaning the TB I unplugged a lot of vacuum hoses. :headbang: In reading some of the similar threads on this site I noticed a lot of the same issues I am having are caused from bad vac lines.
Can anyone advised me where to start looking to check the 4wd system. Photos and diagrams would be a big help. (looks at Bam :D)
Thanks all.
fourwd1
08-10-2009, 03:16 PM
The vac lines only come into play if you have the ADD system, which it sounds like you have.
Here are a few articles that may help.
here (http://www.4x4wire.com/toyota/tech/add/)
and here (http://www.off-road.com/trucks4x4/article/articleDetail.jsp?id=399612)
Zuke76
08-12-2009, 08:39 AM
Looks like all the vac lines are in place... I as hoping for something easy...
fourwd1
08-12-2009, 09:18 AM
Next check to see if the VSV's are getting actually getting vacuum and supplying it to the actuator.
Make sure there is no leak in a vac line or the vac tank.
Zuke76
08-12-2009, 09:44 AM
I will check this weekend since I have to drop the wheel well wall. Whats the best way to check the vac lines?
It almost seems worth the work and $$ on hubs to lock the front diff sleeve and convert to manual hubs.
fourwd1
08-12-2009, 12:12 PM
One of those links has some instructions.
I also have a PDF of the FSM chapter on ADD.
JMF94T100
08-12-2009, 08:47 PM
The same thing happened to me a few weeks ago. It turned out to be a relay under the dash right above the brake pedal. Repalced it and 4wd works again. Could go to dealer and pay 75.00 for it or go on Ebay like I did and got it for 30.00 shipped.
Hartzog
08-12-2009, 09:41 PM
Zuke, i have had a similiar problem before.
do you park on a slight slope??
the reason i ask, is my truck is usually parked on the slope side of the driveway, and similar problems have happened to me, it seems driving the truck around for a while...still no 4wd....usually i will park the truck on COMPLETELY LEVEL ground....leaving the truck in what should be 4wd. a few times i have came out next day....started the truck.......shifted back into 2wd...then back into 4wd without moving...and it worked, but then again, i have had to leave it sittin atleast 24hrs on level grounds to get this to work.
You may be facing a different problem...but then again... maybe this could be somethin to try, as it dont cost $$, lol what can i say...im cheap....but i dont see what i'd put money into the ADD system when i plan on converting to manual hubs
Zuke76
08-13-2009, 06:09 AM
Odd I do park on a sight slope.... I will give that a shot.
I am really considering locking the ADD sleeve system (shown in links) and converting to manual hubs. Has anyone done this?
wendeln16
08-17-2009, 08:38 PM
it may also be the electrical plug in on the transfer case.
Zuke76
09-05-2009, 08:03 PM
I put manual hubs on last weekend in my first step to defeating the ADD system and removing the issues I am having with it. So today I am coasting to a stop on the street (hubs are free)nand decide to test the ADD 4wd system. I shift the transfer case from 2wd to 4wdH and i hear a few clicks from the relay under the dash and feel the front axle lock in and tada the 4wd light comes on! i shift it back to 2wd and the light turn off. I test it 2 more times before I get home and both times it works!!!!
I did notice a lot of clicking noise from the relay under the dash. it clicks 5-8 times before the front axle locks in and the 4wd light comes on, is that common? Or could it be the source of my issues.