stuck in 4wd

sprie · Dec 5, 2024

I have a feeling i am well b******ed.

Having rebuilt the gearbox and it now sitting in an almost complete car, i find that the gearbox is stuck in 4wd ( i have tested this with the car on 4 axle stands, if i wedge something under both front wheels, the wedge gets pushed back).

The high/low level operates OK - pretty sure i have high and low.
The really key symptom is that i can push and pull the yellow knob regardless of whether the high/low is pushed forward or pulled back.
I have checked under the car, and the yellow knob level is pushing the pin in/out OK - it goes in regardless of position of the high/low.

So, this is very wrong.
When i rebuilt the gearbox, i tested it when it was sitting on a pallet and it appeared to operate fine - in and out of 4wd etc.
However, having done a couple of miles of test drives, that appears to not be the case any more.

I think this means there is something wrong inside the front output box - i am wondering if the cross-shaft piece has come off. Or maybe i am missing a spring (which would be odd, given that it worked on the pallet but not impossible).

Given how difficult it is to build a gearbox on a pallet, i am not sure if it is possible to fix this without removing the whole gearbox from the car (the only saving grace is that my new chassis had the bolted cross member option).

My understanding is that whilst 4wd is fine off-road, it is not a good thing to have engaged for long on-road.

Questions:
1) Is there anything i can do that could fix this without removing the gearbox?
2) could i mitigate the issue (at least in the short term) by buying/installing free wheel hubs - i presume they are designed to stop the drive from the wheels to the prop shaft, but i wonder if they also stop the drive in the other direction i.e. from the shaft to the wheels?

kermit_rr · Dec 5, 2024

just to be clear, in high, you should be in 2wd, press the yellow lever and its 4wd
you must select low for the yellow lever to release and pop back up, then return to high - have you got the spring in place on the lever? is it popping back up on its own?
correct, you dont want to be driving on tarmac in 4wd

ear! wots all dem levers for?

http://www.landyzone.co.uk/lz/attachments/f6/3285d1190106022-daft-question-about-gear-selection-what-all-levers-then.zip

www.landyzone.co.uk

https://www.landyzone.co.uk/attachments/what-are-all-the-levers-for-then-zip.3285/

kermit_rr · Dec 5, 2024

you're not supposed to run freewheeling hubs disengaged while in 4wd - you're better off removing the prop until you fix the problem.
the shaft for 4wd is probably just stuck - if i recall you can take the cap off and apply some lube and 'help it along'

tottot · Dec 5, 2024

Just a repeat of @kermit-rr above, do you have that spring between yellow knob and tunnel that makes yellow knob popup?
It is also possible you may have to drive the vehicle a little bit for the gear dog to release and it to go into two wheel drive.

sprie · Dec 6, 2024

tottot said:
Just a repeat of @kermit-rr above, do you have that spring between box and tunnel that makes yellow knob popup?
It is also possible you may have to drive the vehicle a little bit for the gear dog to release and it to go into two wheel drive.

I have the issue when i try the car on axle stands. Tried forward/reverse/high/low/everything, and it is clearly still stuck in 4wd.

Leaving aside the yellow knob for the moment, my understanding is that when the high/low lever is moved forward by the driver, it moves the shifter backward. This acts via 233407 Shaft Coupling on the 4wd dog, moving that backward, which would move it out of 4wd. I remember 233407 was not easy to get in place when i built the gearbox (you had to have the various shafts in line before they were fed into their respective bearings/holes). It obviously was in place, as when i tested the mechanism on the pallet it worked ok, but i am thinking this must now have slipped out-of-place.

I am thinking that even if i had weak (or missing) springs anywhere, the above is a direct mechanism that doesn't rely on the springs.

The yellow knob lever also acts via this shaft coupling.

Given all the postings above, i can't leave this issue unresolved. I think i am resigned to trying to remove this front output box from under the car, investigating the issue and then seeing if it is possible to refit without removing the whole gearbox. What worries me is if i can't see the cause and/or how to avoid a repeat.

sprie · Dec 6, 2024

sprie said:
I have the issue when i try the car on axle stands. Tried forward/reverse/high/low/everything, and it is clearly still stuck in 4wd.

Leaving aside the yellow knob for the moment, my understanding is that when the high/low lever is moved forward by the driver, it moves the shifter backward. This acts via 233407 Shaft Coupling on the 4wd dog, moving that backward, which would move it out of 4wd. I remember 233407 was not easy to get in place when i built the gearbox (you had to have the various shafts in line before they were fed into their respective bearings/holes). It obviously was in place, as when i tested the mechanism on the pallet it worked ok, but i am thinking this must now have slipped out-of-place.

I am thinking that even if i had weak (or missing) springs anywhere, the above is a direct mechanism that doesn't rely on the springs.

The yellow knob lever also acts via this shaft coupling.

Given all the postings above, i can't leave this issue unresolved. I think i am resigned to trying to remove this front output box from under the car, investigating the issue and then seeing if it is possible to refit without removing the whole gearbox. What worries me is if i can't see the cause and/or how to avoid a repeat.

ps. ref the yellow knob "popping up". Mine has never done this, so i have something else wrong. I have spring 561221 on the yellow knob shaft but it does nothing, so i must be missing something. At its bottom, it sits just above the bend in the lever, but the top doesn't act on anything - and i think that is wrong. What should the top of the spring push against?

kermit_rr · Dec 6, 2024

The yellow knob should be straight to push up and down. Pull the yellow knob up as you pull the red knob into low, the yellow knob should pop up. Hold onto it and push the red knob all the way forward. Then you should be in high 2

sprie · Dec 6, 2024

kermit_rr said:
The yellow knob should be straight to push up and down. Pull the yellow knob up as you pull the red knob into low, the yellow knob should pop up. Hold onto it and push the red knob all the way forward. Then you should be in high 2

I have tried holding the yellow knob up as I push the red lever forward, but it stays in 4wd.
From under the car I can move the pin in and out of the shaft a) when red lever forward and b) when red lever back.
So something very wrong.

tottot · Dec 6, 2024

Amended my post above to clarify, The spring on the yellow knob goes between the knob itself and the top of the gear tunnel, there is a bracket with a little cup for it to locate.
It does sound like the pin is not doing its job of holding the dog in 2wd position which is what it should be doing when popped up and in high ratio.

kermit_rr · Dec 6, 2024

It's also likely that the shaft is seized and not moving when the yellow knob goes up. Some lube and a helping hand can sort it.
Otherwise it's not hard to take the lot off the front of the transfer case and give it a clean. If i recall

boguing · Dec 6, 2024

I don't think this is relevant, but it caught me out. Have you got the bulkhead on?

I fitted this piece the obvious way around. That's wrong and moves the pivot so that the high/low lever can't go forwards properly.

steve2286w · Dec 6, 2024

Not seen Blackburn for ages but he had a good download here

Series 3 - Transfer box question - turning wheels by hand with vehicle raised

When one rear wheel is raised off the ground and turned by hand, the front propshaft also moves. To be able to rotate the rear wheel by hand, I also have to raise one front wheel. This is with the transfer box set to 2WD (yellow lever in the up position). It does the same with the red lever...

www.landyzone.co.uk

Should be able to see what’s going on or not using his measurements

sprie · Dec 6, 2024

Interesting. I have jacked the car up and have output box part off (looks like I need to take the oil seal/housing off in order to get the box off). I am worried I won't find what the cause of the issue is.

sprie · Dec 7, 2024

boguing said:
I don't think this is relevant, but it caught me out. Have you got the bulkhead on?

I fitted this piece the obvious way around. That's wrong and moves the pivot so that the high/low lever can't go forwards properly.

View attachment 331308

i think i have got it on the right way around, the horizontal part of the bracket is towards the rear

sprie · Dec 7, 2024

Having now got the box off, and had a brief look, i cannot see anything obviously wrong.

Here is what i think i know: The pin goes in/out regardless of the position of the high/low gear lever. The H/L gear lever is engaging high gear and low gears ok. When it is in low gear, it should push the 4wd selector rod forward, and the pin wouldn't be able to go back in.

My theory is that the Coupling (part no 233407) has come off the H/L rod. I think that would explain why the H/L lever still engages gears ok, but the 4WD rod is not moving (and the pin goes in and out)

The coupling engages 233409 Selector pin on the H/L rod and the same on the 4wd selector shaft. When rebuilding the gearbox, i did not touch these. I am wondering if, for some reason, they need adjustment. The coupling rests against them ok, but there is quite a lot of movement. The workshop manual doesn't say anything about this.

Does anyone know how tight or lose the coupling should be?

steve2286w · Dec 7, 2024

It may be that the shoulder on the coupling bolt keeps some clearance when locknut tightened up, obviously it needs to swivel around without too much play, you need to ensure the coupling is engaged properly with both selector pins when you reassemble, im not even sure if it would go back together if one side was not engaged
looked at my pics when i did mine and cant see any with rods out of housing
looks like you took it apart before checking the measurements on that pdf which might have helped diagnose

you cant adjust the pins as they go through the fixed holes in the high/low and 4WD shafts

tube video here guy explains what happens when the shafts and pin moves around 4mins in, maybe follow this and see if it works ok

sprie · Dec 7, 2024

steve2286w said:
It may be that the shoulder on the coupling bolt keeps some clearance when locknut tightened up, obviously it needs to swivel around without too much play, you need to ensure the coupling is engaged properly with both selector pins when you reassemble, im not even sure if it would go back together if one side was not engaged
looked at my pics when i did mine and cant see any with rods out of housing
looks like you took it apart before checking the measurements on that pdf which might have helped diagnose

you cant adjust the pins as they go through the fixed holes in the high/low and 4WD shafts

tube video here guy explains what happens when the shafts and pin moves around 4mins in, maybe follow this and see if it works ok

I would have done some measuring as per your note but I had started removal process so I was too late.
I am confident that when I rebuilt the box the coupling was in place, and on the pallet it worked ok. But I remember it wasn't easy putting it back together keeping the coupler on. Hence my theory that it was sitting to loosely on bolts, which gives it too much play. Unless I identify anything else, I might try adjusting these so there is a bit of play but only just enough.
Not looking forward to reassembling under the car!

sprie · Dec 8, 2024

what i have found, not sure if anything significant:

First I checked the selector shaft for the 4wd. That slides (the 233416 end) in/out of the transfer casing fine.

I have looked at the two selector pins (233409), one on the selector shaft for 4wd, one on the transfer gear selector shaft. The pins look ok, i can't see any sign of wear. Their shoulders have the same dimensions.

I looked at how the Coupling (233407) was held in place. As you can see in the video, there is some play Obviously it needs to be sufficient lose to be able to easily turn, but i wonder if there is too much play?

The only other aspect i can see if how the connector (538536) sits on the selector shaft. As you can see in this video there is also play here. I wonder if there is too much play (the rod is about 1mm smaller than the width of the hole in the connector). Although I have seen on a youtube video there was some play in this connector. I can't see any obvious signs of wear, it doesn't look mishapen at all.

I still think the Coupling coming off at one end or the other can explain my symptoms in the following scenario:
I can imagine I pushed the H/L lever forwards. The shaft moved forwards. The spring should push the connector (538536) forwards, but if there was a little bit of play, it could snag on the shaft (if it is slightly diagonal on the shaft) even briefly. As the H/L lever is forwards, the Coupling now comes off its pin - never to return.

Obviously i can:
1) refit the selector pins so they fit on the Coupling a bit snugger
2) reattach the Coupling with less play.
and then hope for the best.

I am not sure if it is possible to refit the 4wd box without taking the full gearbox off.

boguing · Dec 8, 2024

It's about five years since I did mine but I don't recall there being anything like as much play as you have in the second clip. Then again, it can hardly be wear.

The only help I can really offer is that I had also run through all the gear permutations perfectly on the bench and I think it was just being unable to get into high once it was in the car. Took it out again, having been convinced by someone who I thought knew better that there was adjustment available inside the box. All fine on the bench. In my case it was that bracket. I'd be looking for something external.

sprie · Dec 9, 2024

steve2286w said:
It may be that the shoulder on the coupling bolt keeps some clearance when locknut tightened up, obviously it needs to swivel around without too much play, you need to ensure the coupling is engaged properly with both selector pins when you reassemble, im not even sure if it would go back together if one side was not engaged
looked at my pics when i did mine and cant see any with rods out of housing
looks like you took it apart before checking the measurements on that pdf which might have helped diagnose

you cant adjust the pins as they go through the fixed holes in the high/low and 4WD shafts

tube video here guy explains what happens when the shafts and pin moves around 4mins in, maybe follow this and see if it works ok

Having taken the parts apart, I now realise i can't "tighten things up": the shoulder on the pins only allow the pins to go in up to a point, and tightening the nuts on the ends of the pins a) has no affect b) i can't even tighten these fully as the little hole for the split pin is covered, so i have to back off a tad.
Unless my pins have stretched (and there is no visible sign of this), i am just going to be putting it back the way it came off/the way it should be.

If/when i get the box back on, i will do the measuring to see if that tells me something else is wrong.

In the meantime, sorry to be stupid but...
I have looked at GrumpyTalks video lots of time, and what is there all makes sense: move that 4wd selection shaft forwards, and it moves the 4wd shaft forwards, moves the dog forwards and engages the 4wd gear. And the opposite.
That all makes sense to me, BUT the red transfer gear level moves forwards for High (/2WD) and back for Low (4WD).

If there was a fulcrum on that lever ahead of where it attaches to the 4wd selection shaft, that would make sense to me i.e. move the top of the lever forwards, moves the bottom of the lever backwards. But there isn't a fulcrum.

Sorry to be stupid but i am obviously missing something.

stuck in 4wd

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