Adjustable 2/3 Fork setup

1941 - 1945, MB, GPW Technical questions and discussions, regarding anything related to the WWII jeep.
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arnob38
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Adjustable 2/3 Fork setup

Post by arnob38 » Fri May 22, 2020 4:18 am

Hello,

i have an adjustable 2/3 Fork, that came with my "reinforced T84 kit"

As per the standard guideline to set it up, I should set a 0.024" gap between the Synchomesh and the 2nd, like this

Image

But with this setup, I end up having the synchro already engaged to 3rd when in neutral position (sorry the comment in is French :) )

Image

I don't think this is right, so i did the setup differently, starting from neutral position, ensuring free play of the 2 synchro rings (that have been properly set after torquing), like this

Image

From here I end up in these positions in 2 and 3

Image

Image

Does it looks OK for you ?

Thanks in advance


Wolfman
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Re: Adjustable 2/3 Fork setup

Post by Wolfman » Fri May 22, 2020 5:36 am

Up front, I am not familiar with the adjustable 2/3 shift fork.
With that said,
If I had not read the instructions and was setting this fork up, I would place the 2/3 shift rail, into normal neutral detent position. Center the fork and synchronizer collar in the center of the synchronizer hub and lock it in place.
See what results you get from trying this.
In second, with the original fork, I am thinking if the synchronizer hub is not up against second gear, it is really close. It all turns together so I don't see any problem with physical contact between the hub and gear.
Mike Wolford
CJ-2A
VEP GPW
Comm./Inst. SEL
AOPA ( 46 yrs)
EAA ( 46 yrs)
4th Inf. Div. - 5th Inf. Div. - 2nd Armor Div. - CIB

dinof
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Re: Adjustable 2/3 Fork setup

Post by dinof » Fri May 22, 2020 6:46 am

Your last photo shows it in 3rd gear. Do you see the "dimple" of the shift plates? And, what markings are on the outside of the transmission case?

Never heard of an adjustable shift fork. That might of come in handy when setting up my transmission.
Dino Falabrino
On the "G" since 1998.
1943 GPW 102310 DOD 3-3-43

arnob38
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Re: Adjustable 2/3 Fork setup

Post by arnob38 » Fri May 22, 2020 9:19 am

Hi,

I can adjust it so that the dimple stays below the synchro

Image

This is what is on the Transmission case.

Image

And you can find the adjustable fork in all the French jeep parts dealers, like these 2

https://jeepest.com/gb/transmission-t-8 ... e-net.html

https://www.jeepvillage.com/index.php?m ... &pid=15705

dinof
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Re: Adjustable 2/3 Fork setup

Post by dinof » Fri May 22, 2020 10:48 am

Yes, adjust the synchro to hide the dimple. Make sure that it's for hiding it in both 2nd & 3rd. Very important. Dam, wish I had that option as I have the dreaded fake French WOF repo case. I had to insert a washer between the fork and the case so that when you shift to 3rd, it would not travel too far and lock in gear.
Dino Falabrino
On the "G" since 1998.
1943 GPW 102310 DOD 3-3-43

Chuck Lutz
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Re: Adjustable 2/3 Fork setup

Post by Chuck Lutz » Fri May 22, 2020 11:07 am

When you assembled the main shaft, you added or subtracted shims where the snap ring is at the rear of the main shaft, right?

By adding or subtracting shims you move the main shaft assembly (including 2nd gear) forward or rearward.
The idea being that you want to set the SLOP on 3rd gear/synchro to match that of the 2nd gear/synchro.
Adding shims reduces the slop on 3rd gear to try to match the slop on 2nd gear.
Removing shims adds slop on the 3rd gear to try to match the slop on 2nd gear.

I believe that if you have TOO MUCH slop and you try to adjust the 2/3rd fork to equally span the synchro plates, you run the risk of exposing the "bump" on the shift plates in either 2nd or 3rd or both.

Assembling the T84 so that the bumps are visible when you are I 2nd or 3rd will eventually cause one or more of the shift plates on the synchro hub to stand UP and you will then not be able to shift into that gear.

NOTE: the adjustable fork will work for adjusting small amounts of slop perhaps, but if the main shaft is too far to the REAR, you will be trying to span too large a gap.
Chuck Lutz

GPW 17963 4/24/42 Chester, PA. USA 20113473 (USA est./Tom W.)
Bantam T3-C 1947

arnob38
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Re: Adjustable 2/3 Fork setup

Post by arnob38 » Fri May 22, 2020 12:56 pm

Hello Chuck,

I strictly followed the various and precious guidelines from this forum , and added shims so that I exactly have the same slop on 3rd gear and on 2nd gear once everything (T-case on transmission + main castle nut) is torqued to specs.
Took me a few attempts to find the right setting, and it is really a pain to torque the main nut...

It is only once this was done that I started to look at adjusting the 2/3 fork.

I was pleased with the adjustable one, as with the standard one (non-adjustable), I was having the bump too much visible on 3rd.

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Re: Adjustable 2/3 Fork setup

Post by Chuck Lutz » Fri May 22, 2020 1:54 pm

If you assembled the main shaft and shimmed it so that 2nd & 3rd had the same slop then the sleeve would not uncover the "bump" unless the shift plates or something else was not the correct length. Are the two circular WIRE springs that hold the shift plates installed UNDER the lip on the bottom of the shift plates?

If the shift rails you use are CORRECT and if you installed both new poppet balls and new springs, you should be able to FEEL when the shift rails are moved forward and rearward. You can feel the shift rail click into 3rd, back into neutral and back further into 2nd gear.
Chuck Lutz

GPW 17963 4/24/42 Chester, PA. USA 20113473 (USA est./Tom W.)
Bantam T3-C 1947

arnob38
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Re: Adjustable 2/3 Fork setup

Post by arnob38 » Sat May 23, 2020 10:09 am

Well... considering that none of the new parts I got had the proper dimensions, and that I had to grind most of them, I am not surprised that this finally does not perfectly fit either :cry:

Anyway, final adjustment is now done.

Ready to close it and put it back in place.

Thanks for ll the advise ! Was super useful :wink:

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Re: Adjustable 2/3 Fork setup

Post by Chuck Lutz » Sat May 23, 2020 11:13 am

Wow....

As long as this assembly does NOT show any of the "bump" on the shift plates when in 2nd or 3rd when you are in either gear, then they won't pop-up and jam the trans. If you can see them in either gear then sooner or later I suspect one or more WILL come loose, stand up and make it impossible to get into that corresponding gear.

I am VERY interested in hearing if the assembly of parts you ground down actually WORKS and for how long. While there was some "fitting" together of parts at the factory, that referred mainly to getting the main shaft positioned so the 2nd & 3rd gear slop was equal.

Please let us know how this all works out.
Chuck Lutz

GPW 17963 4/24/42 Chester, PA. USA 20113473 (USA est./Tom W.)
Bantam T3-C 1947

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Re: Adjustable 2/3 Fork setup

Post by Bluebell » Mon Feb 22, 2021 9:34 pm

Hi Guys, I was wondering who sells the splined shims for behins 2nd gear (mainshaft) Thanks in advance.

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Re: Adjustable 2/3 Fork setup

Post by Wolfman » Tue Feb 23, 2021 9:05 am

RFJP Jeep Parts would be a good first stop.
I think you mean in front of the synchronizer hub ??
That area on the mainshaft is splined.
The area on the shaft between second gear and the step on the mainshaft is not.
Put shims in front of the synchronizer hub, before installing the front snap ring to set the second gear to synchro. clearance.
Then shim the mainshaft forward on final assembly by installing shims between the rear snap ring & spacer and rear mainshaft bearing inner race to move the mainshaft assembly forward in the case, to adjust the third gear synchronizer clearance.
Have all the parts on the rear of the mainshaft, behind the rear bearing in place and the nut is tight.
Also be sure the rear bearing is held tight in the rear of the case while checking the 3rd gear clearance.
Mike Wolford
CJ-2A
VEP GPW
Comm./Inst. SEL
AOPA ( 46 yrs)
EAA ( 46 yrs)
4th Inf. Div. - 5th Inf. Div. - 2nd Armor Div. - CIB

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Re: Adjustable 2/3 Fork setup

Post by Bluebell » Wed Feb 24, 2021 12:21 pm

I have just ordered a quantity of parts from Ron, however he does not list those shims. Who else sells them please?


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