1991 Surf Transfer motor problem

[Grantnz]

Hi to everybody, you have a good forum here!

I have a 1991 Surf that has problems with 4WD. I have extensively trawled this site and the Australian one along with Google and have found no posts that deal with my specific problem.

My transfer case was not engaging properly either on the switch or from the lever going into low. I have successfully sorted the ADD vacuum issues and the selector switch on the lever. I took the transfer case motor off and inspected and tested it. It works well and there is no sign of corrosion. The disc that the electrical contacts wipe on was not removed so I cant see how I could have changed its timing.
The selector rod in the transfer case can be pushed in and out by hand.

Having reattched the transfer motor (several times) I find it will engage 4WD but although the motor operates in both directions, it will not disengage fully which is confirmed by viewing the gears and rod behind the four bolt plate on the side of the motor.

When reinstalling the motor I have had the rod fully retracted with the motor in its fully retracted position, then fitted the large gear that has the pinion on it.
I have also tried it with the opposite setting with the rod in.

Can somebody who has direct experience with transfer case motor fitment please point me in the right direction.

My apologies for a lengthy first post.

Thanks.

I

[Grantnz]

How I fixed it. A long story.

I am posting this because I hope it may help someone else in the future.

I had taken the actuator motor off the vehicle and found that it was OK.

I use the term 'retracted' with regards to the actuator rod being in the disengaged position,withdrawn from the transfer case.

The actuator rod that goes into the transfer case was quite stiff but freed up after being pushed in and out many times. I noticed there was quite a bit of sideways slop in that shaft once the motor was removed.

I had extended the wires to the 4WD engagement switch so I could operate it while I was under the vehicle with the ignition on and watch.. This switch gives only full travel either way. I had also set up a 12V supply to rotate the motor partially by connecting to the two bottom points in the connector with the plug out.( It looks like a 6 point plug but there are only 5 contacts in it.) The lower two are the ones you use.
Reverse polarity to make it run the other way. This is not really necessary but is a good way to test the motor without removing it.

I had the rod in its fully retracted position, and after putting a spot of paint on the small pinion so I could see what it was doing, set the pinion to the fully retracted position and inserted the driven gear and put the cover plate on.

I turned the ignition on and switched to engage.
It went in fine, but wouldnt disengage when I switched the other way.

It was at this point I experimented with having the pinion in various positions and had the actuator motor off and on lots! It needs to be at the limit of its travel. Reassemble with the rod at its matching limit and insert the driven gear

It was now Sunday and I was due to pick up a second hand transfer motor from our local wrecker the next day.

I had reinstalled the motor with the rod (which is spring loaded towards the retracted position) fully retracted. As I pressed the body of the motor assembly over the rod it pushed it in a little and I tightened it up and then fitted the cover over the gears. I tested it in both in and out positions and it still wouldnt fully disengage.

I Took the gear cover off yet again and removed the large gear with some difficulty. As I removed the large gear, the pinion sprung back to its fully retracted position but the rod stayed the same, not quite fully retracted.
I then proceeded to unbolt the motor from the transfer case for the umpteenth time.

EUREKA As I started unbolting the motor there was a click and the spring loaded rod fully retracted. I then tightened the bolts and it started binding again.
After much wriggling of the motor I determined that the rod was binding in the housing as the bolts were tightened. I dont know why it would go in but not retract.
By much experimentation I found that by inserting shim washers between the motor and the transfer case where the top bolt is I could eliminate the binding. I made the shims by punching the appropriate sized hole through a piece of aluminium drink can and cutting to make a washer. As I was trying to fit it I would do up the bolts and see if I could still move the rod with a screwdriver. A bit of trial and error and it was working with four shims on the top hole.

Up into the cab, and I started the engine to ensure vacuum and tried it several times. The 4WD light came on and off at the appropriate times.

It seems to be working fine! Tough luck for the wrecker this time!