lets begin with the FWD to AWD trans swap, and some comparison pics of both the FWD F4A33 and AWD W4A33. the Mitsubishi AWD ATX comes from Japanese market 1990-2000 non-turbo Mitsubishi GTO, there were no FWD GTO's in japan. only north America got the FWD Z11A chassis. the 1990-1995 Mitsubishi Diamante, also used this transaxle if they were AWD.
the W4A33 is also seems to be internally identical to the AWD ATX used in DSM's, with the exception of case being designed to bolt up to the 6G7x series engine. that means almost any upgrade DSM guys do to beef up their AWD ATX, can be applied to the JDM trans being used for this project. i'm not sure if gear ratios changed between turbo DSM/Galant-vr4, n/a AWD GTO, or FWD 3S.
the JDM AWD transaxle for the project, was actually from a 90-92 JDM Diamante, so i had to swap all the sensors/shift solenoids over from the FWD trans to be compatible with theTCU in Thadd's 1995. the diamante shifter linkage and dip stick tube is also specific, so i swapped those over as well to work with the 3S auto shifter mechanism.
the FWD & AWD ATX transaxles are identical with the exception of the AWD trans having provisions for a center diff, output shaft, and t-case mating surface. i'll space these animated pictures out, because they are very distracting to look at in the same screen.
here are a bunch of interesting pics showing of the all three t-cases our platform got, both 5 & 6-speed Getreg t-cases, and the mitsu n/a AWD t-case. the n/a t-case has a strange unused/untapped power output, which gives the n/a AWD t-case a massive appearance despite its smaller input & output shaft diameter. the main housing is also made of iron.
why mitsu gave our 1st gen TT's an aluminum t-case housing, and this 91-92 n/a t-case an iron housing,makes zero sense to me. another thing to note is that the non-turbo t-case is the same one used in AWD DSM's (manual or ATX).
strange unused accessory power output:
the only mod i had to do was to the plate that goes between the engine and trans. i simply trimmed it to accommodate the t-case. if the AWD ATX did not already come with the lower bell-housing cover, i would have had to trim that as well, you can see a pic of the FWD and AWD covers below. also, the FWD bracket that secures the bottom of the bell-housing to the engine block cannot be used. on the AWD ATX, this bracket would connect between the t-case, and engine block for support.
we did not get this bracket with the trans, and i doubt it would even be compatible with the rear TT precat housing in the way (remember this trans was supposed to used with a non-turbo engine). at stock/BPU power levels everything should hold up just fine. but when a turbo upgrade comes, i recommended having a custom support bracket fabbed up.
now on to the 3kgt to R/T rear end conversion. this was done by simply moving the center support bracket up and welding it in place. we did not have the left/right extended R/T end brackets, but the conversion works without them. i believe i only had to drill 4 holes to fit the R/T tails and center panel.
you can see how the 3kgt center bracket has provisions to be slid upwards for use with the higher height of the R/T bumper, and that just what i did.
because of the differences in the way the 3kgt and R/T use the tail/turn signal, i did what i believe is the first install of the 12 wire R/T brake/turn signal controller, in place of the 3 wire 3kgt turn signal relay.
the 3kgt has separate circuits/bright filament bulbs for the brake and turn signal, and the R/T shares one bright filament bulb (per side) for brake and turn signal function. now Thadd has authentic function of the R/T tails.
i usually have someone to monitor the rear seat area for fires when i'm welding underneath, but had trouble finding someone to come over that day. so i setup my PS3 eye camera and laptop to see what was happening inside the car after welding. this way i didn't have to crawl out from under the car 10,000 times to check.
i had a JDM ATX DS imported from japan for Thadds project. as it turns out the front section was all that was needed (it could be mated to the rest of any TT center DS), but it's nice to have the real deal. interesting note, the rear section is half an inch longer to compassionate for the smaller physical size of rear diff used on the non-turbo AWD GTO's. we used a 6 speed rear diff as it closely matches the gearing the stock non turbo JDM rear end would have been. big thanks to Hans for this info, the pioneer of the AWD ATX conversion!
i had to heat up the down pipe, and make some clearance for that massive section of the AWD ATX t-case:
i outsourced the exhaust work to a local muffler shop because i didn't know i could weld regular steel to stainless, oh well, they always do good work. whats not pictured is the flex section where the cat would be, and the single O2 bung that was welded on where it was stock for n/a (i wired the n/a harness to give the TT ECU both the front/rear o2 signal from one o2)
at the end of this, i'd like to give Thadd a big thanks for trusting me with his baby, and being a very straight forward guy in our dealings. although this project went way past my original estimation of completion, he give me the space i needed to get things done without causing me to freak out about time restraints, thus allowing me to get things done right. i'm very proud of the work i did to this car. like past 3S projects before this, it's always sad to open up the shop the next day and not see it there anymore. i'd also like to thank you Thadd for being understanding during some of those strange social disappearances i go through from time to time, you were patient with me with me in times that you didn't really need to be, thanks man.
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