Thread: 4wd selector pin is driving me crazy

I cannot see any way you can have something wrongly assembled to get this effect - I did have a thought that the sliding dog for front wheel drive could be the wrong way round, but I don't think that is possible, and if it was, would put things a lot further out. You need to remember though, that for the pin to drop into the hole, the transfer hi-lo lever (red knob) needs to be right back. And if the gears engaging low range are not engaging properly, due to the teeth being lined up, the lever can't move right back , and the pin can't drop in.

Thanks John.

I had another look this morning before work.

The selector shaft is moving all the way back (red knob backward) as I have tried it without the dog clutch fitted and also without the shaft spring. Confirmed correct position as the detent plunger is in the forward-most detent notch.

Playing with it today I have noticed the following:

1. Some play in the collar that is the forward-end of the selector shaft spring (#15 in diagram). The internal bore may have worn relative to the shaft
2. Some play in the pinch block in front of #15 above (#16 in diagram). Hole through shaft/block may be a little worn.
3. Link #21 may have wear inside forks but I don't know what the nominal gap should be.

I think that the stack-up of all this wear, even though slight, may be causing a 4mm error in the position of the hole. The play isn't purely fore-aft, it causes the rod (#20) to go on an angle, but I think this translates to the hole location when the rod is guided by the hole in the output housing casing.

I cant see what else it can be.

I'm not sure I will be able to source new parts for #21, #19 and # 16.

A possible fix may be to make a spacer to go on the shaft between parts #15 and #16 to shim the rod back the 4mm it needs accounting for the play. I might do that and then test the whole mechanism to see if it operates reliably.

How about simply boring the hole in the shaft out a bit? And/or taper the end of the pin a little so it will help it go in even if a little misaligned?

I had not thought of the possibility of accumulated wear - this mechanism does not usually get an enormous amount of movement.

I've got some G/Bs and GB parts sitting on the floor. The only way I can replicate your problem is when I remove
part no 27,28,29and 30 on the drawing in post #3
.W.

Originally Posted by B.S.F.

I've got some G/Bs and GB parts sitting on the floor. The only way I can replicate your problem is when I remove
part no 27,28,29and 30 on the drawing in post #1
.W.

So you think it could be a detent alignment issue?

I checked the the fork in the transfer case is aligned with the groove in the shaft - but I could try removing this fork and see what changes.

When the selector shaft #9 is fully rearward, is the detent plunger support to sit in the forward-most groove?

Originally Posted by JDNSW

How about simply boring the hole in the shaft out a bit? And/or taper the end of the pin a little so it will help it go in even if a little misaligned?

I had not thought of the possibility of accumulated wear - this mechanism does not usually get an enormous amount of movement.

I think it's a bit too far out for that if I want the pin to reliably drop-down

Originally Posted by B.S.F.

I've got some G/Bs and GB parts sitting on the floor. The only way I can replicate your problem is when I remove
part no 27,28,29and 30 on the drawing in post #3
.W.

B.S.F, from memory the diameter of the selector shaft is 16mm. Are you able to please take a measurement of the internal diameter of part #15? That way I will know if mine is excessively worn.

Sorry, I'm not prepared to dismantle the assembly to take measurements, but I can assure you that no.15 is a very loose fit on the shaft.
.W.