JDM Transmission

[fuel]

I'm thinking 90% sure they are compatible but I wouldn't say they are identical - there would be a reason the 1.8 4WD seems to have a different gearbox to the 2.0 4WD. The 4G37 is another whole different family of engines too, so it's not like the engine is simply just a smaller displacement version of the 4G63 like the 4G62 (SOHC) and 4G67 (DOHC) is.

 

[fuel]

I checked in ASA the part number for the E37A gearbox and it came back as this

You can see the KM221-1-BNH corresponds with the C11BNH stamped on the gearbox, which would explain why the C50 and C51 JDM gearboxes come from the earlier cars with KM225-0-xxx and KM225-1-xxx codes.

The early JDM E39A 4WD non-turbo cars also had a KM221 gearbox just the end code is different, as seen here

Now finding out the difference between BNH and BPH may be the hard part.. I'm hoping it's just a gear ratio difference.

 

[fuel]

I just checked the gear ratios listed for the GGSX on vfaq.com against the brochure above and the gear ratios are identical so I guess that eliminates one possible difference. I would guess that this gearbox would indeed be a replacement for the GGSX box assuming it actually physically bolts on fine.

 

[GSTwithPSI]

Phil, Rich, thanks so much for your input on this. I appreciate your time, and can't say thanks enough!

I can actually confirm the bolt pattern on the bell housing matches that of a standard DSM/VR4 transmission, as it is identical to another the transmission sitting in my garage.

 

[fuel]

oh yeah bell housing bolt pattern is the same through just about all the Mitsubishi engines pre 1990s. I've played around with a few 4G37s before (I had an '89 Galant with one that had 400,000kms on the clock and it was still going like a trooper) and while there are some similarities you can see there are some differences too, with the main one being the size of the flywheel and clutch/pressure plate combo - but in this instance it appears the 4WD 1.8 shares the larger unit of the 2.0 which is unlike that of the FWD 1.8.

 

[mitsuturbo]

Quoting misterfixit:


If you were to swap a 2.846 ratio into a W5M33 you would have to swap the ring gears and the primary reduction set. I do not know if this is possible, but would suspect the differing construction of the centre diff would prevent this.

Rich


You can put in the transmission, and swap out the rear diff for a 2.846 to match, OR you can swap some transmission internals and keep your rear diff.

I would not suggest either one.

I traded a machinist friend of mine a GGSX for a bunch of machine work to be done for myself and some customers i had at the time. Well, shortly after getting the GGSX from me, his little brother grenaded the transmission in his VR4. He decided to get his lil bro back on the road by donating his GGSX trans to the cause. We swapped in the output shaft and front diff from the VR4 trans and had a ridiculously low geared box with a GGSX 1.68 primary drive, combined with the VR4 3.866 secondary. The W5M31 internals and intermediate shaft still drove a GGSX CD, but this CD now drove an output shaft and front diff matched the 3.545 rearend (For noobs, the 3.866 secondary divided by 1.090 tcase reduction = 3.545 rearend)

1.275 * 3.866 = 4.929 final (stock vr4)
1.680 * 3.866 = 6.494 final


It didn't last more than a couple of months of abuse from the mildly modified 4g63, but as i understand it, the kid had a blast driving it around town until the teeth all ripped off of 2nd gear.

 

[misterfixit]

Quoting GSTwithPSI:
Phil, Rich, thanks so much for your input on this. I appreciate your time, and can't say thanks enough!

I can actually confirm the bolt pattern on the bell housing matches that of a standard DSM/VR4 transmission, as it is identical to another the transmission sitting in my garage.



The bolt pattern was one of the points I was making. If you actually have another trans out of the car you could confirm or refute the second.
Can you stand both trans up on their bell housing and measure the height to compare? That would clear it up for all if the bellhousings are the same. Pay particular attention to the position of the trans mount holes.

Yes the 4G3x is a different family from the 4G6x series and they will have a different block length.

Rich

 

[decathect]

you have PM, mitsuturbo

 

[mitsuturbo]

I do know The w5m31 and w5m33 use the same first two pieces of case. I'm sure of that much. The adapter plate and end cover I can't quite recollect with 100% certainty. It's been over 5 years since I had them both apart next to one another but I believe they're the same. There may be a difference in the adapter plate because of the different center diff and vcu. Quoting misterfixit:
Quoting GSTwithPSI:
Phil, Rich, thanks so much for your input on this. I appreciate your time, and can't say thanks enough!

I can actually confirm the bolt pattern on the bell housing matches that of a standard DSM/VR4 transmission, as it is identical to another the transmission sitting in my garage.



The bolt pattern was one of the points I was making. If you actually have another trans out of the car you could confirm or refute the second.
Can you stand both trans up on their bell housing and measure the height to compare? That would clear it up for all if the bellhousings are the same. Pay particular attention to the position of the trans mount holes.

Yes the 4G3x is a different family from the 4G6x series and they will have a different block length.

Rich

 

[misterfixit]

Hence measure the height first off.

Rich

 

[fuel]

I'm hoping that given that the 4WD 1.8 looks to use the same larger flywheel/clutch/pressure plate combo as the 2.0, that the bellhousing on the 4WD 1.8 C11 box is indeed the same size as the 2.0 4WD box.

I can confirm that both the E37A Galant and E38A/E39A Galant use the same MD731017 transmission bracket and MB436541 chassis to transmission mount, so if there were any difference in length in the box the difference would be made up in the location of the tappings on the transmission case itself.

*edit* because I'm bored at work, both the E37A and E38A/E39A non-turbo trans use the same MD726632 case section where the mounting bolts to it.

 

[misterfixit]

Could you then check if the cam side engine mount is the same for all 4G37 engined cars, and if the cam side mount for all 4G63 engine family cars? I suspect they are and the only difference will be elastomer configuration.

If they are then the back of the block is about an inch different in location between the two engine families.

When I put the incorrect trans in my Sava, I was like 'so thats anonother thing they changed to make some work to keep the drawing office busy' and the first thing I tried was to swap the trans brecket.

Could the O/P measure the two trans he has? I would suggest there is one bellhousing casting for the 4g3x family and one for the 4g6x family.

Rich

 

[GSTwithPSI]

Sure, Rich. I only have the JDM box available to measure currently though. The USDM DSM case I had is back in the car now. I can measure the JDM box, and post up the measurements, so maybe someone who has a spare trans out can compare?

 

[misterfixit]

Sounds like a plan.

can anyone oblige?

Rich

 

[strokin4dr]

I have a couple sitting here. What measurements do you need?

 

[misterfixit]

Stand it on the bell housing, then measure to:
1, Top of the trans (Top of the vctu cover)
2, Centre of the uppermost trans mounting bracket bolt hole.
3, Casing parting line at the top of the bell housing casting.

Is this possible?

Cheers,

Rich

 

[GSTwithPSI]

1G/VR4 starter plate.

1G/VR4 starter plate and JDM Transmission

Mounting points all match up, but the starter seems to locate 1/4 inch further from the firewall.

Starter bolts up fine, but is not located exactly the same as a DSM/VR4. I think this would suggest that the trans may use a different flywheel.

1G clutch disk.

Overall case length is approximately 15.5 inches.

As I said before, the trans will definitely bolt up. I am curious as to why the starter is located differently. I'm pretty sure this means the flywheel would definitely have to be different. So, does the GGSX share the same flywheel as the DSM/VR4? This JDM transmission doesn't seem to. Phil, could you run the part numbers for the flywheel on the USDM GGSX, and this JDM transmission and see if they are the same?

Ryan, could you measure the overall length of the DSM/VR4 trans you have, and post how they compare.

Rich, I didn't see your post until just now. I'll have to remeasure at the points you requested.

Thanks again for all those who have contributed here. It's much appreciated.

 

[misterfixit]

Its because its for a 4g37

Thanks for that... now we need the same for a box for a 4g63

Rich

 

[GSTwithPSI]

I have another box I need help with. Part number W5M312VRXC LT5799. Looks like a GGSX trans (W5M31)

-What's it out of?
-What's the final drive ratio?
-Will it work in a Galant VR4? (looks like no due to a GGSX rear differential ratio of 2.846)

Edit: Found this online. Just thought I'd add it here.
Mistubishi Gearbox Codes

 

[misterfixit]

Did you drop a tape measure across the case of that one?

Rich