RS tranny on USDM rear

[Wilfongtsi]

Thanks RTSGVR-4! As soon as 1061 is running thats what I will do, I hope to have my mani, turbo, and o2 back today, but now I need to get a fuel pump assm. anyway THANKS!!

 

[Scientist]

Ok this info helps....jus called a friend that works at the DMV in my country and he did a search based on my licence plates and found out my car is a 1988.

Both sad and happy....sad cause of the year.

 

Quote:
The only solutions if you have this problem are to change the final drive in the transmission, or find a RS rear end, so both match each other.


Co VR4, I talked to a mechanic(20 years with Mitsubishi) that had a USDM tranny and a JDM RS tranny apart at the same time to see if he could do a swap on the final drive but there was a issue with the casing or something, that made it not possible.

So my question is do you know anyone who has pulled off the final drive swap?

What this mechanic did instead, is he swapped all the gears from the RS tranny into the USDM (was not very easy but he made it work). I have ridden in the car and the gearing is incredible compared to my car.

Just wanted to let you know there is another option if you find someone capable of doing the job.

 

^ you can machine the case to fit the usdm final drive into an RS box. hy anyone would want to do this is beyond me, it defeats the purpose of having the RS gearing.

 

^It's the other way round, US diff goes straight into the RS case, the US case needs machining to fit the RS diff. The main reason to change from the RS diff to the US diff is for drag racing, when using the stock rev limit. RS diff and RS fourth gear limit you to about 112mph, whereas the US diff/RS fourth will give about 120ish.

Mike.

 

Good call, i always wondered why someone would do it the way i thought, but makes more sense that way. id still never do it.

 

Just to throw a spanner in the works; I thought I read on here some years back that the Auto DSM 4-bolt ratio was 3.9? Which would make it compatible with the RS box

 

^Nah, it's 3.307.

 

Quote:
Just to throw a spanner in the works; I thought I read on here some years back that the Auto DSM 4-bolt ratio was 3.9? Which would make it compatible with the RS box



you might have read that combining a manual pinion and auto ring gear (maybe the other way around? dont know the tooth counts off the top of anymore) would create a 3.9 rear end ratio. but you cant do this, because rear end gears are matched sets, theyre matched to eachother and wont work with another gear.

 

I'll get it right one day...