4WD Problems
#1
Registered User
Thread Starter
4WD Problems
Hello,
I am having problems with the ADD system lately. My 4runner has manual hubs but I have not disabled ADD completely yet. When I put the shifter (automatic trans) in H4 or L4 the t-case always engages but the front axle (pass side) does not. If I try it a few times sometimes it works eventually, sometimes not at all. I have noticed if I can coast down a hill in 1st gear and then shift into 4WD it will engage sometimes. I think it is a vacuum problem but I am not sure what to look for. I've taken the vacuum lines off and there does appear to be vacuum coming from the engine (where it goes into the check valve). Any help is appreciated so I can still use my 4WD before I tear all the ADD stuff out.
Thanks,
Bryan
I am having problems with the ADD system lately. My 4runner has manual hubs but I have not disabled ADD completely yet. When I put the shifter (automatic trans) in H4 or L4 the t-case always engages but the front axle (pass side) does not. If I try it a few times sometimes it works eventually, sometimes not at all. I have noticed if I can coast down a hill in 1st gear and then shift into 4WD it will engage sometimes. I think it is a vacuum problem but I am not sure what to look for. I've taken the vacuum lines off and there does appear to be vacuum coming from the engine (where it goes into the check valve). Any help is appreciated so I can still use my 4WD before I tear all the ADD stuff out.
Thanks,
Bryan
#2
Contributing Member
Join Date: Oct 2002
Location: NM
Posts: 1,843
Likes: 0
Received 0 Likes
on
0 Posts
Do you hav a manual for your rig? I would look at the vacuum check valves. Seems not enough vacuum is being produced to make the change. Or the fork is getting stuck, and it not being allowed to smoothly slide.....
#3
Registered User
Thread Starter
I've checked the vacuum check valve against the passenger side fender. Actually I replaced it and it didn't help.
If I pull the hose off the vac side of the valve and suck on it, the shift fork seems to have no problem moving the sleeve, and the front locks up fine.
Maybe my engine is not producing enough vacuum for some reason? What about that multiport valve that the vac line plugs into?
If I pull the hose off the vac side of the valve and suck on it, the shift fork seems to have no problem moving the sleeve, and the front locks up fine.
Maybe my engine is not producing enough vacuum for some reason? What about that multiport valve that the vac line plugs into?
#4
Contributing Member
Join Date: Oct 2002
Location: NM
Posts: 1,843
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by az4x4runner
I've checked the vacuum check valve against the passenger side fender. Actually I replaced it and it didn't help.
If I pull the hose off the vac side of the valve and suck on it, the shift fork seems to have no problem moving the sleeve, and the front locks up fine.
Maybe my engine is not producing enough vacuum for some reason? What about that multiport valve that the vac line plugs into?
If I pull the hose off the vac side of the valve and suck on it, the shift fork seems to have no problem moving the sleeve, and the front locks up fine.
Maybe my engine is not producing enough vacuum for some reason? What about that multiport valve that the vac line plugs into?
#5
Registered User
Thread Starter
I am thinking as soon as it's not 12 degrees outside and I have some spare time I am just going to tear out all the ADD stuff. The vac lines don't seem to be plugged with anything.
I'll check out the possibility of an electrical problem later on today, if I don't find anything I guess I'll continue to suck it into 4WD until I can remove all the ADD vac/electronics, I have to get out to lock the hubs anyway...
Thank you for all your input SteveO.
I'll check out the possibility of an electrical problem later on today, if I don't find anything I guess I'll continue to suck it into 4WD until I can remove all the ADD vac/electronics, I have to get out to lock the hubs anyway...
Thank you for all your input SteveO.
#6
Contributing Member
Join Date: Oct 2002
Location: NM
Posts: 1,843
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by az4x4runner
I am thinking as soon as it's not 12 degrees outside ....
#7
Registered User
Thread Starter
Originally Posted by SteveO
Is it really that cold over there? Have you heard of the ACW there in Prescott?
Hmm, I don't think I've heard of the ACW, or I just can't figure out what it stands for. What is it?
Last edited by az4x4runner; 01-20-2006 at 06:52 AM.
Trending Topics
#8
Contributing Member
Join Date: Oct 2002
Location: NM
Posts: 1,843
Likes: 0
Received 0 Likes
on
0 Posts
#9
Registered User
Thread Starter
Ah ok. I hadn't heard of them. I recognize that SAS Tacoma in some of the pics, seen it around town. I only viewed the pics from Alto OHV, having dialup is a drag.
Kind of makes me want to go up there again, it's only about 10-15 mins from my house.
I am surprized they don't have any runs on the local FS roads listed. There are some good trails around here, from easy 2WD to lift and lockers.
Kind of makes me want to go up there again, it's only about 10-15 mins from my house.
I am surprized they don't have any runs on the local FS roads listed. There are some good trails around here, from easy 2WD to lift and lockers.
Last edited by az4x4runner; 01-20-2006 at 07:06 AM.
Thread
Thread Starter
Forum
Replies
Last Post
djpg2000
Tires & Wheels
11
11-11-2020 04:56 AM
TokyoD23
95.5-2004 Tacomas & 96-2002 4Runners
4
07-12-2015 06:01 AM