1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

1991 sambar 4wd activation question - please help!

Discussion in 'Subaru Sambar' started by My58, Nov 22, 2022.

  1. My58

    My58 New Member

    I have gone through all 70 pages of the sambar section of the forum looking for answers on the operation of the sambar 4wd function and I have the manual that's available and have studied the JDM parts catalogs and still do not have a clear understanding of its operation.

    I have been working on my 1991 ks4 and have been struggling with the transmission setup.

    Presently I have the 2 vacuum diaphragm ports on the transaxle tied together. I have done this for both the front and rear transaxle. I believe this keeps it in RWD only.

    When in this setup the drive shaft is spinning even though the front transaxle is supposedly not being used, is this correct? Should it be spinning?

    I have 2 solenoids 1 in the back above the engine access hatch and 1 in the front under the rear of the cab.

    I have the 2 vacuum Diaphragm ports on each transaxle

    I have a vacuum port of some sort on the front transaxle that has a spring (maybe drive lockout?)

    I have the 4wd switch on the steering column

    When the switch is activated I believe the solenoids manipulate vacuum and 4wd is enabled.

    Can anyone please help me and tell me what should get vacuum when activating 4wd and what should not?

    Can someone please explain the process for engaging and disengaging 4wd so I can figure out what's working and what is not?

    Anyone know how much vacuum is needed at those ports ?

    If no-one has info on this stuff can someone please recommend a direction to possibly find someplace that I can get some help with this. Thanks

    Any help and assistance will be greatly appreciated.

  2. Diezelnut

    Diezelnut New Member

    Maybe this will help. Transmission manual page 13 shows vacuum diaphragm for transfer case. That one should engage 4wd.

    http://jdmfsm.info/Auto/Japan/Subaru/--Old Models--/Subaru Sambar KS-KV English Service Manual/
  3. My58

    My58 New Member


    Thanks for the reply. Unfortunately the link doesn't work.

    Are you saying that you believe that vacuum to just that 1 diaphragm activates it? Is the one you were looking at on the front or back transaxle? Do you think both ports on the diaphragm gets Vacuum?

    Thanks for giving this some thoughts.
  4. Drain

    Drain New Member Supporting Member

  5. My58

    My58 New Member

    Thanks Drain,

    That link worked. I have those files but unfortunately it does not explain (to me at least) how things work together.

    I believe the 2 solenoids the 2 diaphragm (2 vacuum ports on each) the 1 vacuum switch(?) With 1 vacuum port on it And the 1 electric switch on the shifter are all involved. But am not sure how to tie everything together.

    Thanks for the link and the effort.
  6. Diezelnut

    Diezelnut New Member

    Perhaps you jack the vehicle, spin the transmission in gear, and apply vacuum to the various servos with a hand vacuum pump. See what happens....maybe post results?

    You should be able to test axle locks by jacking the axle, apply vacuum, spin wheels by hand.

Share This Page