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Discussion Starter #1
Hi I’ve try to research the differences between JDM tranny not MR and US tranny but I haven’t had a good explanations. So my questions are what are the differences between the two besides gearings. I want to get a complete JDM engine and transmission to put in my VR4, would it be a straightforward swap or would I have to modify some parts? Also is it better to get a rebuilt tranny or buy used one? And is there anyone shop in PA that you guys would trust to work on our cars?
 
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The gearing is the only difference besides some of them have some extra BS on the clutch hydraulics that you can get rid of.
 

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Wibbly-Wobbly~Timey-Wimey
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JDM Transmission= MR transmission... they are the same...


If your car is a USDM Six Speed, and you have a JDM 6 Speed, the swap will not work.. you need the JDM rear Differential as well... the gearing is different.


IF you car is a USDM 5 Speed.. You can replace the stock transmission with a JDM 6 Speed. The Differentials are the same. The only hiccup is the drive shaft is about .5" too short... I have about 15K on my 6 Speed swap using the stock 5 speed drive shaft... no issues though....

hope thats helpful :)
 

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resident evil
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Just swap the front differential with gearing from your old one to the JDM one and you will be fine. If you want, you can get a 5 speed rear diff and install that and leave the JDM transmission and you will also be o.k.. If you do the latter, your car will be geared lower (higher numerical), if you do the former, then you will have the same gearing as you had before.
 

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Discussion Starter #5
Ok thanks a lot guys. Now would anyone be able to tell me, how i can tell for sure that my transmission is bad and not the transfer case? When shifting at around 3k and up, it grinds going into 2nd, also when downshifting into 2nd at about 10mph or above it'll also grinds, so is this means that the transmission is bad?
 

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Always Learning
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Ok thanks a lot guys. Now would anyone be able to tell me, how i can tell for sure that my transmission is bad and not the transfer case? When shifting at around 3k and up, it grinds going into 2nd, also when downshifting into 2nd at about 10mph or above it'll also grinds, so is this means that the transmission is bad?
Can just mean the 2nd gear synchro or even a crapping out clutch. Open that bitch up to see.
 

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Hi I’ve try to research the differences between JDM tranny not MR and US tranny but I haven’t had a good explanations. So my questions are what are the differences between the two besides gearings. I want to get a complete JDM engine and transmission to put in my VR4, would it be a straightforward swap or would I have to modify some parts? Also is it better to get a rebuilt tranny or buy used one? And is there anyone shop in PA that you guys would trust to work on our cars?
What year is your car? 5 speeds are the same, that's what I did bought a low mile JDM engine and transmission
 

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Discussion Starter #9
my vr4 is a 96, just wanted to clarify some stuff out before jumping into and buying a new used transmission or rebuilt one. Thanks a lot guys.
 

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JDM Transmission= MR transmission... they are the same...


If your car is a USDM Six Speed, and you have a JDM 6 Speed, the swap will not work.. you need the JDM rear Differential as well... the gearing is different.


IF you car is a USDM 5 Speed.. You can replace the stock transmission with a JDM 6 Speed. The Differentials are the same. The only hiccup is the drive shaft is about .5" too short... I have about 15K on my 6 Speed swap using the stock 5 speed drive shaft... no issues though....

hope thats helpful :)
So just to clarify b4 I order..i have a 93 rt tt 5 speed..i can use a jdm s speed..or from the post above I can also use a 5 speed?
 

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Wibbly-Wobbly~Timey-Wimey
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So just to clarify b4 I order..i have a 93 rt tt 5 speed..i can use a jdm s speed..or from the post above I can also use a 5 speed?
You can use either.

the JDM 6 Speed will work,

As well as the USDM/JDM 5 speed

if you are buying a 5 speed...becareful of the output shaft

early Early JDM 5 speed had a weaker output shaft 18Spline (thin version)
Later/early JDM 5 speed/and USDM 5 speed had the 18spline (thicker version)
Later 5speeds had the 25 Spline output shaft

all 6 speeds have the 25 spline
 

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JDM Transmission= MR transmission... they are the same...


If your car is a USDM Six Speed, and you have a JDM 6 Speed, the swap will not work.. you need the JDM rear Differential as well... the gearing is different.


IF you car is a USDM 5 Speed.. You can replace the stock transmission with a JDM 6 Speed. The Differentials are the same. The only hiccup is the drive shaft is about .5" too short... I have about 15K on my 6 Speed swap using the stock 5 speed drive shaft... no issues though....

hope thats helpful :)
Ok so I’m having a issue with my 1991 3000gt vr4 after doing the 6 speed jdm swap and trying to use my stock driveshaft and something is causing the rear tires to skip and feals like there is binding almost happening like right in the center by the transfer case. Is it because the driveshaft is too short??? I mean I know the driveshaft isn’t suppose to go in all the way but I’ve read that some people use the factory 5 speed driveshaft with no issues. Just trying to figure out what my next route is.
 
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It sounds like your 6 speed actually has usdm gearing.

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I do have one jdm 6 speed setup here, but not sure we want to sell it.

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Also have some 6 speed rear diffs we could build for you

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Money pit owner.
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does the JDM 6 speed tranny, installed in place of a US 5 speed tranny, with OEM US 5 speed differential allow for the increase in top speed to 200mph? Or does that required a full US 6 speed tranny and differential swap?
 
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does the JDM 6 speed tranny, installed in place of a US 5 speed tranny, with OEM US 5 speed differential allow for the increase in top speed to 200mph? Or does that required a full US 6 speed tranny and differential swap?
I would have to check the gear math but should be no problem hitting 200 with enough power. Jdm 6 speed is only geared 7 percent lower than usdm 6 speed

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