ADD 4wd problems

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ADD 4wd problems #844846 11/02/07 07:43 PM

Joined: Aug 2004

Posts: 20

South Dakota

CMH

Need a Spot

I have a 95 t100 and just noticed that 4wd will not engage(worked fine last sping). I located the vacuum lines on the acuator and firewall and they same to be intact with no cracks.

Here is the strange thing, while trouble shooting I reversed the lines on the acuator and then 4wd engaged as soon as I shifted into 4wd?

My first thought was a bad line so I switched them back to std on the actuator and reversed them at the electric switches, same thing instant on?

89 ext cab 22re 4x4 267K miles (for sale)
94 Land Cruiser Factory lockers
95 T100 4x4 ext cab

Re: ADD 4wd problems [Re: CMH] #844847 11/03/07 01:48 AM

Joined: Aug 2003

Posts: 676

Oregon

garym

Rock Warrior

Seems like if you don't put it into 4wd for a while either the switch, the relays, or something else does not always make contact. When you put in in the second time it either freed up or the corrosion was rubbed off the contact. Mine was doing the same thing and now I try to shift it in at least 1x a month and no problems since.

1997 T-100 4X4 Xcab,Warn Hubs
02 Camry LE
2008 Yaris

Re: ADD 4wd problems [Re: CMH] #844848 11/04/07 12:21 AM

Joined: Apr 2006

Posts: 658

Honeoye NY

wsquaredodie Offline

Rock Warrior

follow factory recommendations. Run the 4wd every month for a few miles. Run the low as well

trafdlo

Re: ADD 4wd problems [Re: CMH] #844849 11/04/07 03:18 AM

Joined: Aug 2004

Posts: 20

South Dakota

CMH

Need a Spot

Thanks...but mine still dos not work unless I swap the vac lines.

My guess is that when I swap lines it leaves the add system engaged (kind of like leaving the hubs locked in a non add truck). Technicaly 2wd till I shift to 4wd but the axles and diff are spinning.

To troubleshoot the system I need to know what ports should have vac applied in 2wd and in 4wd.

89 ext cab 22re 4x4 267K miles (for sale)
94 Land Cruiser Factory lockers
95 T100 4x4 ext cab

Re: ADD 4wd problems [Re: CMH] #844850 11/04/07 08:14 PM

Joined: Apr 2006

Posts: 658

Honeoye NY

wsquaredodie Offline

Rock Warrior

I have the pdf files for my 93T from the factory service manual. Can find everything for the tranny ops except for vacuum systems. Perhaps someone out there can help on where to look. Spent about 30 minutes looking through stuff and it must be hidden. Do not see anything in my Haynes manual either.

trafdlo