what normally goes wrong on turbo 4EAT

[bry]

I think all of the 4EAT are Jatco, not just SS trans.

It is possible Nissan might have used a 4EAT in the second generation 300zx. Jatco was Nissan back then.

You said the SS trans is a bit different than the N/A. I know they add a few friction and reaction discs to the forward clutch, what else is different?

The Trans-go kit and a "few select things"? Are you talking about extra discs, and hardened splines and maybe planet teeth?

Everyone listen, "NO ADDITIONS ABOUT MANUAL TRANSMISSIONS"

THIS THREAD IS FOR AUTOMATICS ONLY!!!! unless you have advice to offer about an auto, then hold your breath, please!!!

[93forestpearl]

the turbo transmissions are built to a higher spec from the factory. there is one more clutch disk in the forward clutch(gears 1,2,3,4) the high clutch (gears 3,4) and the 2-4 brake band servo piston has a lager apply area (same band). also the transfer clutch has 1 more clutch disk (AWD).
what does all this mean, more torque capacity. of course the non turbo tranny shifts will flare on a turbo motor. your almost doubling the input torque. the tcu's are calibrated differently to match the trans and motor also.

That is the basics on the turbo vs, N/A tranny.


A 700 whp tranny is possible with a computer controlled tranny, but it costs money. There are levels in between, so get ahold of Derek if you need to know more (whitelegacyguy).

[bry]

fifth gear.... i suspected there may be more to the turbo, than just some extra friction discs... i come from gm land and run 200-4R trans (v8 240z), but only certain codes. some codes are a completely different valve body, accumulators, centrifugal weights, etc. i don't know for certain, but it may be that the 4eat-t valve body pistons, galleys and springs could be slightly different... but i have no experience in that matter...

[i_c_the_light]

So hang on, with the differences in phase one transmissions, then with my 1990 JDM Legacy GT, I am able to replace the transmission with a 1997 V3 WRX transmission without having any plug n play issues with the wiring and/or the tcu? There will be no issues using the Legacy tcu?

I've noticed that on the Legacy transmission, the wiring for the shifter is a different setup compared to the WRX transmission. On the Legacy transmission, the harness is integrated into the shifter mechanism. On the WRX, there is a plug for it. Anyone know what I mean?