Ln130 surf ADD help

[Cass]

hey all, iv got a wee problem and cant figure out where to start lookin at to fix it.
when i push the 4wd button the 4wd light comes up on the dash and everything is fine, but when i start moving i can hear it clicking in an out an the light flickers and clicks in and out of 4wd all the time, and when i put it in low range it comes out of 4wd all together.
any ideas on how i can fix this as its really annoying.
also, i dont no if this is would have any effect on it but it had a 2lt in but has been replaced with a 3l.
any help will be much appreciated

[mike]

hey all, iv got a wee problem and cant figure out where to start lookin at to fix it.
when i push the 4wd button the 4wd light comes up on the dash and everything is fine, but when i start moving i can hear it clicking in an out an the light flickers and clicks in and out of 4wd all the time, and when i put it in low range it comes out of 4wd all together.
any ideas on how i can fix this as its really annoying.
also, i dont no if this is would have any effect on it but it had a 2lt in but has been replaced with a 3l.
any help will be much appreciated

I believe its vacuum operated if i remember rightly so check that the lines are ok, failing that check the servo unit is ok and the throwing arm is working ok. it moves a collar over and when the collar is engaged thats when the switch mounted beside the vacuum, which detects engagement, lights up the dash. My light doesnt even come on anymore but everything is still engaged and working fine, but then i've done a lot of water work and suspect the switch is dirty or crapped out.

These bits are located on the front of the diff. youll see a little black tube and a couple of wires, one to the front and one to the rear i think.

hope this helps a little

[taz01]

try looking at vacum solanoids drivers side hoses connect to alternator?

[UBZ]

Sounds like a vacuum issue to me. If you are getting the 4wd light onthe dash 4wd must br activating in transfer and front diff , but under load thier is no vacuum to hold it in 4wd.

Put the truck up on jack stands and check that the front drive shaft is engaging and that front diff is has engaged passenger side axle.
This should tell you if the transfer or front diff is at fault. Solinoids in engine bay are for front diff , transfer had a vacuum pump on the back