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Converting a W55 4x2 transmission into a W56 4x4

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25K views 9 replies 4 participants last post by  inmyownsummerami  
#1 ·
Some have asked here on the PBB how to convert a 4x2 tranny into a 4x4. It's a bitch and not worth the time unless you already have both transmissions and want to use one as a parts donor.

What you need is:
4x2 tranny
Rear case from a 4x4 tranny
Output shaft from a 4x4
Counter shaft from a 4x4


What you do is swap all the gears, syncros and bearings from the 4x2 output shaft onto the 4x4 output shaft.

Make sure both donors are from the same year. These are D series because it is what I had laying around.

Internally, they are almost the same shiet. All the bearings on both transmissions had identical numbers and matched each other. All but 1st and 2nd gears are also identical.

So here's how you do it...

Remove transmission first dummy!
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Remove bellhousing, it's dirty in there.
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unbolt this
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then this
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Remove the main casing bolts, pretty easy so far.
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Go take a leak and drink a beer because it's all downhill from here
 

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#2 · (Edited)
Split the cases with a rubber mallet. A dead blow has metal inside and will knock off bungs, ask how I know...
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This is the reason I dove into this in the first place. This can't be good.
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Remove as shown and use rubber mallet to knock off the front case.
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Yikes! old and new. This is what happens when you don't rebuild it right the first time. The 4th gear syncro didn't go into it's notch when putting the cases back together. I didn't notice and put the cases together anyhow; it didn't want to close up. I backed it out and it had ruined the syncro. Put a new syncro in but I didn't think I damaged the bearing, guess what? It ran a few hundred miles with the damaged input bearing. It made a loud winding noise in any gear but 4th. It finally lost all but 4th gear and I limped home 40 miles in first low and 4th gear, haha that was fun.
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Now do the same to the 4x2 transmission; same steps. This is what they look like side by side
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#3 · (Edited)
A clean work bench and vise makes this job a hell easier. Use bolts through the bottom of the plate so you won't damage the steel. If you don't use bolts at least use wood otherwise it won't seal.
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Now start taking these guys off. This one was stripped so I got my handy dandy welder to attach a bolt. Worked like a charm.
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Remove all the caps, springs and balls
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Remove first and second forks, and reverse idler gear; use a sharpie to mark all of these. In earliar years I believe the reverse was located in the front housing. At any rate, the D series has them in the rear casing.
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Here's what it looks like at this point
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#4 · (Edited)
Remove the reverse fork and assembly. This has a couple of smaller pieces that work together. Don't lose them! You can see the ball and there is also a small pin.
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Almost bare.
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Remove 5th counter gear, bearing and spacer. This puller is bitchen; Harbor Freight 5" special.
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Remove this hub and don't lose the small spacer next to the roller bearing.
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This is the only special tool that you will need to buy or make. I made each side with two 1/4" plates welded together, drilled and notched. This pushes against the reverse gear to force the 5th gear, bearing and coupler off. My tip here is to turn each bolt 1/4 to 1/2 before turning the opposite bolt. It is a slow process but you do not want to cock the 5th gear. It will not come off and will either bend the plates or strip the bolts/nuts.
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#5 · (Edited)
Currently at this stage..
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Now take the rear gear off. I have always been able to take this off using only my hands; no puller.
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Now take the bearing cover and snap rings off. You will need a heavy duty snap ring plier to get this tranny job done. Don't waste your money on cheapies here; they will bend like mine. Invest in this one that Marlin sells.
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Clean as a whistle. Now slide them out at the same time. Make sure you cradle them so they don't get damaged.

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Finally out; beer break.
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Now do the same for the other transmission
 

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#6 · (Edited)
From left to right:
4x2 Counter, 4x4 counter (carnage!), 4x2 output shaft, 4x4 output shaft
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My batteries died and I didn't feel like walking to buy more, this being my dd. So no more pics. From here you decide if you want the lower 1st and 2nd gearing 4x4 offers or the higher gearing in 4x2. My 4x4 parts are toast so I used my 4x2 internals in the 4x4; i now have the higher gearing. Honestly i have used both in the same truck weeks apart and I didn't notice a thing.

You will need a press (20 ton HF works very well) and a bearing seperator (again HF; I'm a harbor freight ho).
Remove first gear assembly, flip around and remove 3rd gear assembly, then 2nd gear assembly. These are straight forward and at most will need 2x4 and 4x4 pieces of wood. Now remember the order you took them out and assemble them onto the 4x4 output shaft. Keep track of the 4x4 and 4x2 1st and 2nd gears as these will be different sizes. Dont' mix and match these and use them with the appropriate counter shaft. Now put everything back together and use blue locktite along with a torque wrench.

Print out the toyota fsm when you are going to do this. I left out some of the smaller steps like checking for straightness and oil clearances. I checked them when I rebuilt this the first time around.

http://personal.utulsa.edu/~nathan-buchanan/93fsm/manualtrans.html

The only reason I did the conversion was because I couldn't get parts to fix the 4x4 during the 3 day weekend. I knew the 4x2 was in good condition and needed to get to work in a few days so I went for it.
 

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#7 ·
Differences in 4x2 fly and clutch (left) and 4x4 (right). The 4x4 is a bit larger in diameter, the 4x4 flywheelhas a w ider step to accomodate. You can use the 4x4 fly wheel and clutch (as a set) on a 4x2 or vice versa.
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And this is how I fit a w56 and dual cases in a 2wd with a 3" body lift. This is my on going junk. Full write up once I am done in a few months..
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