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BigJimnyMeet (North) 2024 (12 Jan 2024)


BigJimnyMeet 2024

14th July 2024
Parkwood Nr. Leeds

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Transfer lever jumping back into 4WD

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29 Nov 2023 18:42 #252486 by moadi
When you say I need a diff, do you mean I have to replace the whole thing or I can keep what I have and just swap the crown wheel with one from the years and model you mentioned?

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29 Nov 2023 19:20 #252489 by Busta
You only need the ring gear and pinion, but in practice it's easier to buy a whole diff than just those parts.
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30 Nov 2023 13:27 #252496 by fordem

When you say I need a diff, do you mean I have to replace the whole thing or I can keep what I have and just swap the crown wheel with one from the years and model you mentioned?


The crown wheel & pinion should be kept together as a set, I'm tempted to phrase that as MUST be kept together as a set, but, in a life or death scenario you can certainly swap one with out the other, just be aware that you will destroy both and in a very short space of time.  The last step in manufacturing the gear set is to lap the crown wheel & pinion as a matched pair, after which they should never be separated.

It's also important that you recognize that you can NOT swap the pinions between the different ratios, they might be both eight tooth pinions, but the angle & size of the teeth are going to vary, what I've said above is specific to swapping the crown wheel or pinion between identical gear sets.
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30 Nov 2023 13:53 - 30 Nov 2023 13:53 #252499 by moadi
I see, thanks alot for explaining, I’ll have to find a whole diff with 10 bolts and a ratio that matches my rear diff then transfer the e-locker into it.
Last edit: 30 Nov 2023 13:53 by moadi.

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01 Dec 2023 15:59 - 01 Dec 2023 16:15 #252546 by moadi
Ok so I managed to count crown wheel & pinion teeth in the rear diff and also the crown wheel teeth in the front diff through the holes (I couldn’t see the front diff pinion tho, only the crown wheel) and here’s what I found

Rear diff
Crown wheel - 43 teeth
Pinion - 10 teeth
Ratio: 4.3

Front diff
Crown wheel - 45 teeth
Pinion - I’m guessing 11
Ratio : 4.090

Using what I learned from the amazing people on this thread:

4.3/4.090 = 1.05

So this means for every full rear wheel rotation I get 1.05 front wheel rotation.
And this is the reason that when I put it back into 2WD after driving in 4WD it doesn’t disengage and I have to reverse, correct? 
Last edit: 01 Dec 2023 16:15 by moadi.

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01 Dec 2023 18:45 - 01 Dec 2023 18:49 #252551 by facade

Ok so I managed to count crown wheel & pinion teeth in the rear diff and also the crown wheel teeth in the front diff through the holes (I couldn’t see the front diff pinion tho, only the crown wheel) and here’s what I found

Rear diff
Crown wheel - 43 teeth
Pinion - 10 teeth
Ratio: 4.3

Front diff
Crown wheel - 45 teeth
Pinion - I’m guessing 11
Ratio : 4.090

Using what I learned from the amazing people on this thread:

4.3/4.090 = 1.05

So this means for every full rear wheel rotation I get 1.05 front wheel rotation.
And this is the reason that when I put it back into 2WD after driving in 4WD it doesn’t disengage and I have to reverse, correct? 


 
Correct, so 5 rotations of the rear puts the front out (it moves further) by 5 x .05 = .25 turns.

You don't have to reverse. you could just jack up one wheel, and there will be a "twang" and the wheel will flick round to relieve the tension.

Or you could bounce it over a kerb like an Alvis Stalwart/Saladin/Saracen/Salamander- when the wheel leaves the ground it unwinds..

Or just do nothing and soon there will be a "bang" as something breaks and you won't have the wind up any more.


It needs matching diffs before you use 4wd or you are going to break something.   I wonder if the front one was broken, because it didn't match the rear and the mechanic matched the broken one that he took out.

If it suddenly breaks, go back to the last thing that you did before it broke and start looking there :)
Last edit: 01 Dec 2023 18:49 by facade.
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01 Dec 2023 18:51 #252552 by moadi
I see, thanks.
Yes I already took out the prop shaft until I sort this out.

I doubt the old one was broken because of this as I never had issues with it for years and it always disengaged 4WD with no issues, never had to reverse.

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02 Dec 2023 09:41 #252573 by Busta
Just to confuse matters slightly, if you are using 4wd as intended e.g. in situations where the tyres can easily slip, the difference in axle speed from having the wrong diffs actually makes very little difference and won't cause any harm. There is a far bigger discrepancy between axle speeds when you turn a corner, even if you have exactly the same diff ratios. The transmission is designed to be able to cope with this as long as you are driving in appropriate conditions.
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03 Dec 2023 19:35 #252595 by moadi
I see, well right now it stays in 4WD even when I’m offroading (slippery surface) unless I reverse

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