DIY: Gearbox Disassembly

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shiggz
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DIY: Gearbox Disassembly

Post by shiggz » Mon Mar 13, 2017 3:02 am

Below outlines the step by step process of disassembling the FTO gearbox (F5M42) if you plan to replace any bearings, or perform a gearbox rebuild.
This guide only shows the disassembly of the gearbox, excluding the methods of removing it from the car and replacing bearings/gears/synchros.

Firstly, remove the gearbox from the car, and obtain all necessary tools.
The disassembly is very straight-forward and only requires basic tools.
Sealant is required for the assembly of the gearbox. The recommended Mitsubishi sealant is the "Threebond High Temp RTV Silicone".
In addition, the counter-shaft seal/cap is also needed (Part number: MD746157), as the original cap needs to be broken to be removed.


Step 1: Remove the throw-out bearing and retaining spring. Then place gearbox in the position shown below:


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Step 2: Remove the inspection cover (6x 10mm bolts). Use a rubber mallet to hit the edge and seperate the cover from the gearbox to expose the reverse idler gear.


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Step 3: Remove the single bolt as shown, which holds the reverse idler gear in place. Hold the idler gear as the bolt is removed, and take the idler gear out of the gearbox from the inspection hole. The blue arrow shows where the bolt protrudes to hold the gear.


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Step 4: Flip the gearbox to the position shown below, and remove the two sensors (Reverse and Speedo sensor). The reverse sensor is held in by the attached nut, and the speedo sensor is held in by the single bolt. The speedo sensor needs a little wiggle to be removed once the bolt is taken off.


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Step 5: Using a deep socket, remove the 4 nuts holding the gearbox mount/bush onto the gearbox


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Step 6: Remove the 3, 17mm bolts as shown


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Step 7: Remove the 2 bolts as pointed to release the first section of the shifter. Check this for any stiffness/play.


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Step 8: Remove the 4 bolts holding the actual shifter unit in the gearbox, including the 1 retaining bolt.


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Step 9: Break the seal by using a rubber mallet, and wiggle the control housing / shifting unit out of the gearbox.


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Step 10: Flip the gearbox back onto the bell housing, and remove all the outer case bolts as illustrated. There are 14 bolts surrounding the perimeter of the case, and 2 additional bolts which hold the entire case together. The 2 bolts are located here, inside the bell housing.
Note: All 16 bolts are completely identical.


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Step 11: Remove the counter-shaft seal/cap. Mitsubishi's recommended procedure is to hammer a flathead screwdriver into the cap, and to pry the cap off. This is not difficult to do, but do not drive the flathead too far into the cap, only enough to pry the cap off, otherwise you'll run the risk of damaging the internals. See the below pictures to reference how much depth you have to drive the screwdriver into the cap. Also note that the best place to drive the screwdriver isn't in the centre of the cap, but towards the sided, as pointed by the arrow (Just incase the screwdriver protrudes the cap too deep).

The new cap will be needed when assembling the gearbox (MD746157)


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Step 12: Using circlip pliers, spread the circlip as demonstrated, to drop the counter-shaft from the gearbox. You will hear a 'clunk' sound as the whole gearbox internals drop to the bell-housing side of the gearbox.


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Step 13: You are now ready to split the case open. Using a pry-bar or large flathead, pry the case from the 2 indents shown, on either side of the box. Break the seal, and then lift the top case off the gearbox. This casing of the gearbox is the lighter section of the entire gearbox.

The internals of the gearbox will now be exposed, as so:


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Step 14: Using a spanner, remove the 3 illustrated bolts and underlying circular plate, which are the only bolts holding the gearing system on the gearbox.


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Step 15: The entire gearing component can now be removed from the gearbox. Using a rag to drape the gears, hold the gearing system, and pull it off the gearbox. The gearing assembly is one of the heavier parts of the gearbox.


Your gearbox is now successfully disassembled! You can now replace particular parts of the gearing system, or send it to a specialist.



Other General Important Notes:

[*]Use the gearbox manual for assembly procedures

[*]Apply the Threebond sealant to all sections of the gearbox that were disassembled, and apply the sealant as per directions on the manual

[*]Handy Tip: Before sealing and bolting the gearbox case together, perform a test fit to see that the top of the case fits perfectly ontop of the bell-housing case - Spread the circlip as the case is being put together, such that the circlip is spread over the bearing and is close to seating into its groove

[*]If the circlip is sitting on the bearing, but is only a few mm's of its groove, you can turn the gearbox upside down, and give it a shake or drop it lightly onto a plank of wood to get the countershaft to drop into position, allowing the circlip to seat into position



Quick comparison of what the Wavetrack LSD looks like:

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This gearbox disassembly was performed on Rob's gearbox, where both the inner and outer bearings needed to be replaced on the input shaft.
The below video shows the comparison between the old worn inner bearing, and the new Mitsubishi / Koyo Bearing:
https://www.youtube.com/watch?v=y927Lsg ... e=youtu.be
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Rob Furniss
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Re: DIY: Gearbox Disassembly

Post by Rob Furniss » Mon Mar 13, 2017 3:50 pm

That looks like a great guide, are special tools required for replacing any of the internals? (press etc?)

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mezje
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Re: DIY: Gearbox Disassembly

Post by mezje » Mon Mar 13, 2017 8:44 pm

Ripper guide, awesome pics and well written, let's hope the image stay hosted unlike all the old imageshack etc ones :'(

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shiggz
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Re: DIY: Gearbox Disassembly

Post by shiggz » Tue Mar 14, 2017 5:39 pm

Cheers :)
Yeah, well I'm keeping all the photos on my laptop incase that does happen!

No real special tools apart from what the guide states. There may potentially be 1 torx bolt on the box (that holds the reverse idler gear, assuming it hasn't already been replaced with a normal bolt, like this gearbox had)

To remove the bearings/synchros/gears you'd need special tools such as a 3-jaw-gear-puller, but I'm not going to attempt to replace anything major. The 2 bearings we replaced were easy to do. We hammered them off carefully, applying pressure equally across the circumference of the bearing, and to insert a new bearing we used my ball-joint-pressing-kit, to hammer them on. But again, you really need to be careful with this method so that the bearing goes on equally and not at an angle.
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spetz
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Re: DIY: Gearbox Disassembly

Post by spetz » Tue Mar 14, 2017 7:25 pm

Fantastic work there Shiggz, great addition to the DIY knowledge base

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Vectose
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Re: DIY: Gearbox Disassembly

Post by Vectose » Tue Mar 14, 2017 10:46 pm

Great stuff.

Another thing to keep in mind is whenever you replace bearings/internals you should always reshim the box as clearances may not be the same.
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Re: DIY: Gearbox Disassembly

Post by Bennoz » Wed Mar 15, 2017 9:45 am

Where's that video of me doing Dan's box? :lol:
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Re: DIY: Gearbox Disassembly

Post by bjk » Wed Mar 15, 2017 11:16 am

Bennoz wrote:Where's that video of me doing Dan's box? :lol:
Probably on Pornhub somewhere :cheeky:
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Vectose
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Re: DIY: Gearbox Disassembly

Post by Vectose » Wed Mar 15, 2017 11:20 am

In the "I'll edit/upload it when I want to/can be stuffed" pile along with updating my build thread.
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dazjb
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Re: DIY: Gearbox Disassembly

Post by dazjb » Sat Aug 05, 2017 1:04 am

Is there anywhere this guide can be downloaded? None of the pics are showing anymore :(

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shiggz
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Re: DIY: Gearbox Disassembly

Post by shiggz » Mon Aug 07, 2017 10:57 am

I'll have to update the pictures; upload them somewhere else :(
Stoopid photobucket
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