idiot's 4EAT question - (probably been asked 100 times)

[Rubie_25GT]

Would a 1999 Subaru legacy gt 4EAT bolt up to and work with/handle a completely stock 2002 wrx motor?
I am assuming the TCU for a WRX 4EAT would be needed?
I kept reading that the Legacy phase II 4EAT was the same as the WRX's?

Thanks for any input I can get!

PS I've read the bit about the transmissions and motors, but am confused on the differences between the 4EAT transmissions :smt009

[geckoboy86]

Almost any Subaru transmission can be compatible with almost any Subaru EJ engine.. Subarus are Legos after all. The issue is will it handle the power.

I think you need to match TCU to the 4EAT so no swapping there.

I don't know about if they are the same. There is a bit of a gap in HP but then the auto WRXs were kind of an oddball.

The differences in transmissions are normally in terms of ratio and build quality. They all are good but some are better then others.

If you ever swap transmissions remember that the rear differential ratio needs to match.

[Rubie_25GT]

That's what I was thinking. I have been told that it puts up with DVD h6 which is something like 230 hp. So I'm figuring that 245 wouldn't be a problem if I'm not beating the bejesus out on the trans.
Thanks for the input! :smt023 I'm looking at wry motor now but am not swapping immediately so I might obtain a trans later.

[Huffer]

Don't use the 4EAT with a WRX motor. You'll hate it, it'll hate you. The 5EAT is better and more fuel friendly also.

[StatGSR]

^ idk, semi built 4EATs can be beastly behind a wrx motor, not sure what the difference is between a wrx 4EAT and a older legacy 4EAT is though.

[Rubie_25GT]

Well I have a 99 so it has a phase 2 trans. Since the wrx motor is about 2 years difference I figured Subaru would find it to be more cost effective to make a trans that would deal with most of their motors. Plus the 4eat would be temporary anyways. Will manual swap if I get a hold of a 5speed

[mike-tracy]

The 1st year of the phase II tranny is a total POS, my mom in law's 99 Legacy SUS is on it's second one at 114k miles, and the replacement is starting to shift less than smooth. Craigslist usually has a couple 99 Legacy owners ISO a phase II tranny...

Secondly, I'm not aware of anyone successfully swapping in a 5eat? It is a completely different animal in every way other than it bolts up and can be found in the same FD ratios. If you have some links I'd like to read up.

[harrymaneuvers]

Um... I am going on 242,XXX miles on the original tranny with zero problems (aside from a worn tranny mount)...


Being perfectly honest, I drive the car harder than it should be about 90% of the time... for the last 100k miles.

about 70% of the shifts are above 4500 rpm...

I drive from Sacramento to Portland about 8 times a year and EVERY time I hit some of the steep inclines on I-5, I downshift to 3rd and have no problem going up hill, with a COMPLETELY full car at 75 - 80 mph and 5,000 - 6,000 RPM's. Sometimes for 5+ miles in a row.


Tranny seems pretty solid... at least over the last 100k miles.


Sidenote: Hoping we can find out if the phase 2 4eat is the same in the leggy as it is in the wrx... if so... POWER MODE IN THE WRX FTW!!!

[mike-tracy]

Your car is a rarity! Congrats. Seriously though, my last job was in a wrecking yard and if a newer subie didn't come in from being wrecked, or HG's, it was a phase II tranny failure. Or with blown hg's and a dying tranny, etc.

I know what you mean tho - I experienced the same thing with my 96 Subaru's 4eat. 299k miles and counting. Last 90k miles on an ej25d and I absolutely flogged the thing. Ej25d failed, and I swapped in a low mileage ej22 and it's still running hatefully strong. I absolutely despise it, and when I get the car back I have a 5mt lined up to swap in.

[Dead91silvia]

How is it that those of use that beat the living crap out of our Auto's, still have the same one and the people that baby them get replaced?! :smt017 :smt005

I'm thinking that if you use a non turbo trans with a turbo motor, it will die fairly fast if you beat it. That being said, I'm thinking of tubroing my ej25 and seeing how long both last! :twisted:

[harrymaneuvers]

Only thing I can think of is that I replace (3 drain and refills) the ATF every 40,000 - 50,000 miles with a new filter too even though technically there is no service interval.


I have been running AMSOIL ATF and GL-5 from the get go...

Also, I know there are mixed feelings on this, but I utilize my "3" gear quite often when driving up hills...

If I start to go up hill and I can see and feel the car slowing down... I will let my foot off the gas, shift into 3, then back on the gas and it is 100x better than just pushing my foot down harder and harder until the TCU downshifts.

No massive clunk