New 5EAT owner with a few questions

[Mobius118]

Hello all,

I bought a 2005 Legacy GT limited last month and while I'm not new to Subarus (previous car was a 2003 WRX with a VF39), there are a few differences with the LGT and I was looking for a bit of guidance.

 

My main concern here is the transmission. I had about 380hp at the crank in my WRX, which was a 4EAT, and besides adding trans cooler and some good synthetic fluid, the transmission was always solid. Here, with the 5EAT, I'm hearing quite a few stories of blown transmissions. The car had 74k miles when I bought it in Sept, I've since put just over 3k on it and am a relatively aggressive driver.

 

I have a transmission cooler sitting in my garage and am hoping to install it ASAP (every day I drive without it I feel as if I'm shortening the 5EAT's lifespan). Problem is, I'm not quite sure how to go about the install, as the one on the WRX was installed by a mechanic. The LGT seems to lack a good mounting position, and I'm also unsure of which direction to install the cooler in conjunction with the radiator, ie: does the trans fluid flow from driver's side to passenger side, or vice versa?

 

The other question I had is in relation to changing the trans fluid. As I bought the car used, I don't have access to any service records, as that would have been up to the previous owner. I'm sure it wouldn't hurt though. Some here have listed unplugging the trans fluid hose from the radiator and pumping the transmission dry with the engine idling, though it doesn't sound smart to run the car with an empty trans. I could do a drain and fill, but it seems I need a special socket to open the drain plug (is this the hard to find T70?)

 

Lastly, is a VB mod absolutely necessary? I know it adds to the shift speed, but is there any mechanical protection it offers? So far I'm stock and will be adding an AP next week, but come spring I intend to Auto-X the car and may eventually move up to a VF52 after the suspension is to my liking.

 

My apologies if this is a lengthy post, I did some searching and couldn't come up with anything satisfactory (and the trans cooler install thread sends me to a dead link), but any input is greatly appreciated. Thanks in advance!

[notthesnail]

There's some interesting stuff going on in the Transmission forum: substitutes for the IPT VB mod; line pressure tuning; TCU reverse engineering for direct trans tuning.

 

I think the big problem with the 5EAT stems from line pressure. Once you add more power, there isn't enough to keep from burning out the clutches. Once they're done, the trans is a mess. So it's looking like the forum is headed in the directing of a fix for that. The VB mod adjusts line pressure, among other changes.

 

As for the trans cooler, look under the car on the driver's side. There are two lines coming out the side of the transmission. The upper one is the return line, lower is supply. I think it flows in the passenger side of the rad and out the drivers, but follow the lines to be sure. I believe you want to hook the cooler up after the rad. I mounted mine to the center upright in front of the rad, hoses coming out the bottom and feeding through a gap around the driver's side of the rad. I had to tip the rad back to get access to the back of the upright. I used bolts and nuts through existing holes.

 

I did a fluid change at the same time. Disconnected the return line, idled the car until a couple or three quarts came out, shut it off, topped it up. Repeat until the fluid starts coming out bright red. Should take 10-11 quarts. Bought a case of Amsoil ATF, which can also be used for power steering.

 

Drain and fill only gets a quart or two out of the pan, and it is a T70, which isn't that hard to find any more.

[Mobius118]

Thanks for the advice! The guy who sold me the cooler from our local NASIOC club got back to me and said that the passenger side is the return line. I just managed to bolt the cooler in once through an existing hole, and unfortunately could not find another bolting point, so as it sits now it is half strapped with a bungee cord (ricey, I know, but it started raining as I was installing it, and the dark crept up on me). I managed to flush about six quarts out, and I will probably do another six in a couple of weeks. The fluid that came out was a dark brown, so I'm very glad that I did it. The car feels much smoother, at least for the five minutes I drove it after the install/flush.

 

I'm also looking at the threads dealing with modifying the line pressure, and it looks like a worthwhile endeavor, though I'm not confident enough in my programming abilities to take the risk of damaging something. I asked a tech at the dealership about any reflashes from the factory, and all he told me is "don't mod your car, the trans isn't built for it". Guess not all of the techs are mod friendly...