Newbie Tech Section Often asked technical questions can be asked here

4x4 will not engage

Thread Tools
 
Search this Thread
 
Old 10-25-2009, 07:22 AM
  #1  
Registered User
Thread Starter
 
craigory1983's Avatar
 
Join Date: Oct 2009
Location: ottawa,ontario,canada
Posts: 8
Likes: 0
Received 0 Likes on 0 Posts
4x4 will not engage

Hey I'm new here and i just bought a 1990 Toyota pickup 4x4 5spd 22re
i tried the 4x4 and thought it worked because when i shift from 2h to 4h i can hear a click in the dash but the 4x4 light does not come on, so i tried 4l and it felt like it was working because the gear ratio was so low so i figure the transfer case is ok. so i tried using 4h to get out of a little jam and the front wheels were not spinning.
what are the things i should check first
please help
Old 10-25-2009, 07:40 AM
  #2  
Registered User
 
Kiroshu's Avatar
 
Join Date: Oct 2007
Location: NC
Posts: 2,747
Likes: 0
Received 3 Likes on 3 Posts
Connectors on transmisson. Any hanging off or not in the right place? Wheel hubs locked?
Old 10-25-2009, 07:47 AM
  #3  
Registered User
Thread Starter
 
craigory1983's Avatar
 
Join Date: Oct 2009
Location: ottawa,ontario,canada
Posts: 8
Likes: 0
Received 0 Likes on 0 Posts
Well I looked underneath and didn't see anything hanging or anything and if I'm not mistaken the front hubs are always engaged I think the diff has something engage the axles
Old 10-25-2009, 07:51 AM
  #4  
Registered User
 
Kiroshu's Avatar
 
Join Date: Oct 2007
Location: NC
Posts: 2,747
Likes: 0
Received 3 Likes on 3 Posts
Do you manual lockers or auto? if namual you have to get out and turn them.... if auto then no.... you could jack the rear off the ground and put it in 4wd and see if it pulls the truck off the jack lol. Or jack it all up on stands and see..... if the front wheels are not turning and the light is off.... then something is disconnected.... look hard... i hard the same issue after i did a clutch in a buddys truck i forgot to reconnect one lil connector and it kept the 4wd from working......
Old 10-25-2009, 08:46 AM
  #5  
Registered User
 
Team420's Avatar
 
Join Date: Feb 2008
Location: the great Maine wilderness
Posts: 2,048
Likes: 0
Received 4 Likes on 4 Posts
vacuum lines, or electrical connectors to the front diff.
Old 10-25-2009, 06:20 PM
  #6  
Contributing Member
 
eric-the-red's Avatar
 
Join Date: Oct 2003
Location: Port Coquitlam, BC
Posts: 2,593
Likes: 0
Received 6 Likes on 6 Posts
If it's got ADD read this.
http://www.off-road.com/trucks4x4/ar....jsp?id=399612
Old 10-26-2009, 01:49 AM
  #7  
Registered User
 
Yorkie's Avatar
 
Join Date: Aug 2008
Location: Keswick, ON
Posts: 29
Likes: 0
Received 0 Likes on 0 Posts
I had exactly the same problem. It was a vacuum line the got connected incorrectly the last time it was in the shop. Follow the vacuum line up from the ADD up to the passenger side of the engine bay. It goes into a small black box and comes out the other end. With the engine running, pull the line and see if there is any vacuum there.
Old 10-26-2009, 02:23 AM
  #8  
Registered User
 
thook's Avatar
 
Join Date: Sep 2005
Location: NW Ark on wooded ten acres...Ozarks at large!
Posts: 8,656
Received 15 Likes on 13 Posts
Originally Posted by craigory1983
Hey I'm new here and i just bought a 1990 Toyota pickup 4x4 5spd 22re
i tried the 4x4 and thought it worked because when i shift from 2h to 4h i can hear a click in the dash but the 4x4 light does not come on, so i tried 4l and it felt like it was working because the gear ratio was so low so i figure the transfer case is ok. so i tried using 4h to get out of a little jam and the front wheels were not spinning.
what are the things i should check first
please help

The click in the dash means the switch at the t-case works, but the light not coming on means the actuator is not moving over to engage the diff w/ the axle. So, somehow you are not getting vacuum or the actuator itself is not working right.

Look at the front diff for the two vacuum lines going to the actuator to right (as your facing it) of the diff. If they aren't disconnected there and/or have no holes in them, trace them back all the way to the two vacuum switches they go to. Not sure where they are on your truck. They're under the hood on top of the pass. side wheelwell in a 2nd gen 4rnr. Anyway, make sure they are connected there and that the switches function = creating vacuum. If all appears well, the hoses may just be switched around.
Old 10-26-2009, 02:15 PM
  #9  
Registered User
Thread Starter
 
craigory1983's Avatar
 
Join Date: Oct 2009
Location: ottawa,ontario,canada
Posts: 8
Likes: 0
Received 0 Likes on 0 Posts
thanks for all the help guys. It seems the steel connector for the vacuum line rotted away so now i just have to figure out if i can fix it or if i have to replace the add
Old 10-27-2009, 04:28 AM
  #10  
Registered User
 
thook's Avatar
 
Join Date: Sep 2005
Location: NW Ark on wooded ten acres...Ozarks at large!
Posts: 8,656
Received 15 Likes on 13 Posts
How badly? Can you get a pic?
Old 10-27-2009, 06:10 AM
  #11  
Registered User
 
JShaffer0525's Avatar
 
Join Date: Dec 2008
Location: Winston Salem
Posts: 329
Likes: 0
Received 0 Likes on 0 Posts
not really sure exactly how add works but would just switching to manual hubs fix this and negate the need for the vacuum lines? probably a noob question but im just trying to learn!
Old 10-27-2009, 06:12 AM
  #12  
Registered User
 
Team420's Avatar
 
Join Date: Feb 2008
Location: the great Maine wilderness
Posts: 2,048
Likes: 0
Received 4 Likes on 4 Posts
no... with the add flanges, your hubs are always locked... the problem u are having is that your front diff is not engaging. Gotta fix thos vacuum lines, or manually lock the diff. then add the manual hubs.
Old 10-28-2009, 06:06 PM
  #13  
Registered User
Thread Starter
 
craigory1983's Avatar
 
Join Date: Oct 2009
Location: ottawa,ontario,canada
Posts: 8
Likes: 0
Received 0 Likes on 0 Posts
i managed to drill out the broken connector and pressed in a piece of 3/16 brake line as a new connector and reconnected the vacuum line now the 4x4 works great. thanks for all the replies and suggestions i really appreciate it
Old 10-28-2009, 06:26 PM
  #14  
Registered User
 
SigEp4Runner's Avatar
 
Join Date: Sep 2006
Location: Portland Oregon
Posts: 309
Likes: 0
Received 0 Likes on 0 Posts
This same dang thing happened to me after my buddy rebuilt my transmission!! Thanks to this thread I can show him where he f-ed up or just do it myself. Since I paid to have the thing fixed to begin with, and I got stuck once, I might as well have him do it.
Old 10-29-2009, 09:07 PM
  #15  
Registered User
 
thook's Avatar
 
Join Date: Sep 2005
Location: NW Ark on wooded ten acres...Ozarks at large!
Posts: 8,656
Received 15 Likes on 13 Posts
Originally Posted by craigory1983
i managed to drill out the broken connector and pressed in a piece of 3/16 brake line as a new connector and reconnected the vacuum line now the 4x4 works great. thanks for all the replies and suggestions i really appreciate it
I was going to suggest something like that. S'why I asked how bad it was broken. Congrats to a DIY'r...
Old 11-03-2009, 10:04 AM
  #16  
Registered User
 
323gtx's Avatar
 
Join Date: Jun 2009
Location: can
Posts: 2
Likes: 0
Received 0 Likes on 0 Posts
hey guys im having a similar problem with my front diff not engaging im getting the light on the dash coming on so im assuming that the actuator is engaging the switch and i have check and do get vacume from the right hoses at the add what else could be wrong if the actuator is engaging the light transfer case is good front drive shaft engages when in 4wd
does there need to be a certian amount of vacume to engage the diff over and less vacume to engage the switch?
help would be nice

cheers
frank

Last edited by 323gtx; 11-03-2009 at 10:06 AM.
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
westonian18
86-95 Trucks & 4Runners
2
05-01-2020 06:38 AM
mussy01
The Classifieds GraveYard
13
12-13-2016 08:20 PM
defrag4
Vehicles - Trailers (Complete)
0
07-31-2015 10:50 AM
tomczaksdiesel
86-95 Trucks & 4Runners
0
07-26-2015 10:35 PM
jgwerth
93-98 T100s
0
07-16-2015 03:23 PM



Quick Reply: 4x4 will not engage



All times are GMT -8. The time now is 05:00 PM.