4wd not engaging ! !

[glennyboy]

Hi to all its been a while since ive been on but am having issues with my 4wd not engaging and wondered if anyone has any ideas what my problem could be ??

I havnt used the 4wd for a few months and was helping my dad spraying the other day and was getting a bit slippy down the track so i went to engage the 4wd hi by the button but nothing happened no 4wd light nothing so i tried 4wd low and still no 4wd , tried moving backwards and forwards in both hi and low and not a thing so carried on and just made it where we needed to be . on the way home as i was driving at about 5-10 mph i pushed the 4wd button in and it just started beeping at me with the 4wd light just flashing but not engaging tried stopping and starting but still nothing
started having a look today so here is where i am

tested 4wd button works fine
fuses tested all ok
ADD relay under footwell not clicking when engaging 4wd button and no light on dash
good vacuum from engine and pipes to both VSVs and down to ADD unit on front diff are in good condition
swapped vsv hoses round and ADD unit engages and disengages when swapped back
had a quick test of the relay and working correctly but 4wd button has no influence on relay either on or off
when driving and engaging 4wd button 4wd light just flashes and beeps at me

im thinking it may be an ecu controller fault within the 4wd unit itself or maybe the transfer box motor on the back maybe but not sure just wondered if anyone has had the same symptoms before on there surf ?

any help or pointers will be gratefully received !

[glennyboy]

Ok so I think it's the 4wd ecu itself it has power down to it and the 4wd switch earth's the unit but nothing coming from the ecu to the add relay or vsvs so have sourced a second hand unit and try that first
Fingers crossed!

[NiftyNev]

Does front tail shaft lock when button is on?

Nev.

[glennyboy]

Hi nev
No the front shaft does not lock when the button is pressed or in 4L and it doesn't seam there is any power going to the transfer case shift motor either
Also just been out testing again and the ecu is now clicking when the button is pressed but not the add relay lol
Also noticed the transfer motor felt quite warm after I started her up for a few mins
This is driving me crazy

[glennyboy]

so I was bored tonight and decided to remove the transfer case motor as it wasn't doing anything when I powered it up separately and here's what I found
Removed the 4bolts from passenger side cover and removed small gear wheel then removed wiring and 3 mounting bolts from the housing itself, it didn't wanna budge so after a bit of wiggling and turning back and forth
Whilst spraying wd40 at it it finally came free off the shaft
(Which I guess shouldn't have been so tight as the shaft should move freely under operation) Once I had it on the bench and marked all the location of the gear wheels etc I took it apart to find it full of gunky mess and the 4 magnets for the motor had spun inside the motor end cap and the glue had come away from the housing which I guess is why it wasn't working!!
Cleaned everything out re-glued the magnets back in place really greased all the components and put it all back together and hey presto the motor turns freely when operated via a battery and rotates fully in both directions
Not convinced this is all of my problem but will refit in the morning and see what happens as when I was testing earlier there was no power the the motor anyway but atleast I know the motor now works as it should

[glennyboy]

Some pics of what I found

[NiftyNev]

The Shift Motor has a vent hose on it so when it perishes, or you go too deep in water, the motor fills up. If it works ok now, install a new hose and route it somewhere high and safe.

Nev.

[glennyboy]

SUCCESS!!!! 4wd is now fully operational after refitting the shift motor!
Refitted it this morning and hey presto it all works like a treat!!
It's strange nev as inspected the vent hose and it's still like new no perishing or anything maybe it's been changed before but changed it anyway so fingers crossed it will be ok now!!

[Paff]

Result

[yorta2]

Nice photos, glennyboy. I found them quite interesting. Well done and good luck.

[glennyboy]

Thanks guys! it was good to finally get it sorted without costing me anything, and I thought the pics might help anyone else out who comes across this issue

[danielsprague]

Good to hear that. My actuator popped itself out of the T-case while testing with the bolts taken out (on a 3rd Gen, but the design is very similar) and I'm not so sure how it all goes back together.

I assume when the shift rod is fully disengaged from the T-case (i.e. it is in 2WD), the clam shell gear is fully wound up and on the limit switch?

As far as I can tell, the engaging motion of the actuator (i.e. pushing the shift shaft into the T-case) is halted by one of the transfer switches recognising that 4WD has been engaged....

Any ideas??

Thanks!

[glennyboy]

Hi m8 when I installed mine the shift rod from the transfer box was fully out (2wd) and I just powered the motor up so it was hard over (ie pulling the shift rod out) then installed the idler gear and tested that it made full travel into 4wd and back into 2wd and works fine every time not sure if it's correct but works a treat so far lol