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420A Simple Swap question

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Zen Hakuren

Probationary Member
Jan 9, 2023
Olympia, Washington
Will an Evo 8/9 engine pair with the stock 420a transmission and if not what trans would I want to swap to?
There are no other useful swap opportunities for transmissions on 420A engines, or 420A transmissions on other engines. The 4G63 conversion will require the Evo transmission to swap, and it's just not worth it.
For the 420a driveline you would need a Chrysler based transmission, maybe something from an SRT-4? I am not sure on that but that is where I would look if I wanted to upgrade.
The SRT4 transmission is an NVT-850 which has the same belhousing bolt pattern as the GS/RS NVT-350. So if your trans wouldn't work then that one wouldn't either. The only thing that Evo engine has in common with your current drive train is the orientation of engine/trans and a mount that "almost" lines up. If you're using a Chrysler engine, use a Chrysler transmission. If you're using a Mitsubishi engine, use a Mitsubishi transmission. Simple question, simple answer.
There are some Hyundai's and Kia's out there with automatic transmissions that would bolt up to the Evo block, but I am not sure if those cars even came with a manual transmission option and even if they did the stock transmission would not be able to handle the output of a Evo engine without mods.
The 3g/4g eclipse transmission can be modified to hold the power better, the weakest part the 3g/4g fwd transmission is the spider gears in the diff, I had one blow the diff pin and one of the gears out of the side of the transmission case on me once, and it somehow held together long enough to get me home it was ridding on 3 of the 4 spider gears, most of the used 3g/4g transmissions also have worn input shaft bearing cages, due to owners neglecting to change the gear fluid often enough or possibly from abuse, defects, or a poor design, and when the input shaft bearings wear down they make a sound similar to a bad throw-out bearing, so if you decide to go with a 3g or 4g eclipse transmission an upgraded diff might give you some more durability, and then there is the axle joints which are also a known weak point to deal with, an evo transmission would be my recommendation on a swap like this, especially if you plan to make a lot of power however a fwd 3g/4g transmission is useful to have if you just want to get your project running and moving, a fwd 3g or 4g eclipse transmission can work temporarily until you can collect everything to awd swap it, and as long as you don't beat on the car it might hold up long enough till you have all the required parts.
This thread title is a bit misleading. I don't believe there is a "Simple" solution. ;)
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