Newbie Tech Section Often asked technical questions can be asked here
Sponsored by:
Sponsored by: CARiD

problem with ADD

Thread Tools
 
Search this Thread
 
Old Feb 23, 2009 | 03:19 PM
  #1  
Joshua4507's Avatar
Thread Starter
Registered User
 
Joined: Feb 2009
Posts: 98
Likes: 1
From: Califorina
problem with ADD

I just bought a 1991 toyota because it has a 22 re and a five speed the down fall is the auto locking hubs are not locking in i suspect a bad switch the problem. but i don't know where the swich is located. is it on the t-case or on the shift lever?

any help is apreed

Last edited by waskillywabbit; Feb 23, 2009 at 03:30 PM.
Reply
Old Feb 23, 2009 | 03:25 PM
  #2  
904_runner's Avatar
Registered User
 
Joined: Mar 2008
Posts: 3,870
Likes: 4
From: Chico, California
does it have auto lockign hubs or the ADD

Automatic differential disconnect...
Is there a bunch of vacuum lines on the front diff?
Reply
Old Feb 23, 2009 | 03:27 PM
  #3  
Joshua4507's Avatar
Thread Starter
Registered User
 
Joined: Feb 2009
Posts: 98
Likes: 1
From: Califorina
how can you tell the differance?
Reply
Old Feb 23, 2009 | 03:28 PM
  #4  
waskillywabbit's Avatar
Banned
iTrader: (-1)
 
Joined: Jul 2003
Posts: 3
Likes: 20
This will help you see what is going on, not necessarily your solution:
http://www.4x4wire.com/toyota/tech/add/

Auto hubs and ADD are NOT the same thing.

Reply
Old Feb 23, 2009 | 03:29 PM
  #5  
Joshua4507's Avatar
Thread Starter
Registered User
 
Joined: Feb 2009
Posts: 98
Likes: 1
From: Califorina
yes there are vacuum line on the front of the diff
Reply
Old Feb 23, 2009 | 03:29 PM
  #6  
904_runner's Avatar
Registered User
 
Joined: Mar 2008
Posts: 3,870
Likes: 4
From: Chico, California
EDIT" nvm

Thanks wabbit.


I had a problem with my ADD system, it was no longer getting vacuum to keep the shift fork locked, which wouldn't allow the front wheels to put the power to the ground.
I ended up bypassing the VSV's and ran a vacuum line directly from the ADD shift tube to the engine, this kept constant vacuum on my shift fork.
Before that i added manual locking hubs so i could unlock them and not have the cv's spin.

If you are going to do this you will need manual locking hubs.

Last edited by 904_runner; Feb 23, 2009 at 03:31 PM.
Reply
Old Feb 23, 2009 | 03:31 PM
  #7  
waskillywabbit's Avatar
Banned
iTrader: (-1)
 
Joined: Jul 2003
Posts: 3
Likes: 20
Auto hubs were 84-89 only I believe, so he has ADD.

Some more info:
http://www.4x4wire.com/toyota/tech/autohub/

Reply
Old Feb 23, 2009 | 03:31 PM
  #8  
toyota4x4907's Avatar
Registered User
 
Joined: Sep 2008
Posts: 4,355
Likes: 2
From: middle of no where Alaska
Werent auto locking hubs phased out/replaced by ADD in like '87..'88 or so?

so it has to be ADD

EDIT: Wabbit said it before i did

Last edited by toyota4x4907; Feb 23, 2009 at 03:33 PM.
Reply
Old Feb 23, 2009 | 03:35 PM
  #9  
Joshua4507's Avatar
Thread Starter
Registered User
 
Joined: Feb 2009
Posts: 98
Likes: 1
From: Califorina
in my eyes the cure would come in the form of a solid axle swap. but untill then i want to see if i can make what i have work. also my 4 wheel drive light does not come on. any idea where the swich is ?
Reply
Old Feb 23, 2009 | 03:37 PM
  #10  
904_runner's Avatar
Registered User
 
Joined: Mar 2008
Posts: 3,870
Likes: 4
From: Chico, California
Well when you throw the TC in 4wd it sends a signal to the vsv to creat vacuum.

Your light will only come on if that shift fork is locked
Reply
Old Feb 23, 2009 | 03:39 PM
  #11  
Joshua4507's Avatar
Thread Starter
Registered User
 
Joined: Feb 2009
Posts: 98
Likes: 1
From: Califorina
is there a switch that is trigered when you put it in 4 ?
Reply
Old Feb 23, 2009 | 04:33 PM
  #12  
4Crawler's Avatar
Contributing Member
20 Year Member
iTrader: (3)
 
Joined: Jun 2002
Posts: 10,821
Likes: 34
From: SF Bay Area, CA
Originally Posted by Joshua4507
is there a switch that is trigered when you put it in 4 ?
Yes:
- http://www.off-road.com/trucks4x4/ar....jsp?id=399612
Reply
Old Feb 23, 2009 | 05:01 PM
  #13  
Joshua4507's Avatar
Thread Starter
Registered User
 
Joined: Feb 2009
Posts: 98
Likes: 1
From: Califorina
thanks for the help. now i understand my truck better. and what i need to do next
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
cars-guy
Pre 84 Trucks
7
Aug 16, 2020 06:59 AM
jasonty
Pre 84 Trucks (Build-Up Section)
41
Dec 23, 2018 01:00 PM
dumpster84
84-85 Trucks & 4Runners
25
Apr 30, 2016 06:03 AM
Ladythump
95.5-2004 Tacomas & 96-2002 4Runners
22
Nov 9, 2015 08:53 AM
Michael oaks
86-95 Trucks & 4Runners
18
Jul 27, 2015 11:47 AM




All times are GMT -8. The time now is 05:25 AM.