Reprogramming the 5AT...

Has anyone cracked the 5AT transmission yet?

There is no TCU mod. IPT is your best bet for 5EAT mods. They offer VB mods, torque converters and full rebuilds (claimed good to 400whp).

You can check them out here;

http://www.importperformancetrans.com/

And yes, since you're in Australia and I have a feeling you're about to ask, they do ship international.

What exactly are you looking to do to it, or what are you hoping to gain by cracking it? We could offer alternatives.

And yes, since you're in Australia and I have a feeling you're about to ask, they do ship international.

What exactly are you looking to do to it, or what are you hoping to gain by cracking it? We could offer alternatives.

 

I want more rear split - in current form, the dyno shows as much as 70% front, 30% rear. A bit more rear bias would be good as well as faster shift times.

^ that is surprising, always read we're supposed to be more rear-biased (60/40?) than the MT.

Definitely not - very front biased. I've managed to get myself beached and get some major front-left wheelspin whilst trying to get out of a steep driveway in the wet, just like an inferior FWD. Rear wheels did nothing to push me out. Pretty useless, actually

 

The front/rear split shifts depending on load and rpm, it seems. It gets to about 60/40 front/rear at some point.

^ hmm, i don't feel that at all...i've had my fill of fwd/rwd, and under most conditions (understanding vtd is employed) my car definitely feels and acts like the 45f/55r i've seen it tagged as in a few sources.

 

what year is your model, tangcla? also see that you're in oz, jdm trans?

2004, 5EAT. I believe the transmission is the same across the world.

The 5EAT split is 55.3% on the rear, 44.7% on the front. Your rear wheels didn't push you out tangla because the center diff did not lock-up. Since it's got viscous coupling, it takes a few seconds for the differential fluid to heat, shear and lock up the diff. Reprogramming the TCU would do nothing on the traction bias since you'd also have to mod the center diff and change the bias under normal conditions from a mechanical standpoint.

I think the best idea is to get to know how the auto AWD system is set-up and should you decide it's not something you like, you may be looking at trading the car in as there's not much you can do about it.

Manuel trans has the viscous center diff. Auto trans has a variable clutch pack in the center diff controlled with a solenoid and hydro pressure from the trans.

So if that happens again - what should I do to get rear traction?

Let her keep spinning and it will lock up eventually

 

tmp, who is Manuel? Is he Spanish? Joking aside, you are correct although I am under the impression the auto center diff also relies on fluid and is no better at locking up faster

So if that happens again - what should I do to get rear traction?

 

Have some people push the car.

Have some people push the car.

Strange. So far everyone has said its a 45/55 front/rear split. When I drive in my works parking structure after it rains I can fishtail just by accelerating in a turn. The concrete is incredibly smooth.

^the 5EAT is particularly tail-happy when you try/push it. More traction on the rear plus lighter-weight on that end = fun times

Drives a bit like both, actually. You only really need a very little bit of RWD push to get the stability.

Manuel trans has the viscous center diff. Auto trans has a variable clutch pack in the center diff controlled with a solenoid and hydro pressure from the trans.

Guys, Manuel is back again!

VDC FTW in those situations!

VDC FTW in those situations!

I think VDC was only available in 2005 or 2006+ vehicles... no?

I think VDC was only available in 2005 or 2006+ vehicles... no?

I'm not sure about international models, but I think VDC was first introduced in the US Legacy in 2008.

Let her keep spinning and it will lock up eventually

 

That's the theory, but in practice I have not seen it work. They don't ever "lock up" the way we'd all like them to. One of our fellow forum members got stuck, had two wheels spinning at opposite corners, and wasn't going anywhere. We gave the diffs plenty of time to "lock up" but they just don't.

 

From the inside I've experienced this in two cars (my LGT and my old car, a 325ix with center and rear VCs). VC diffs will transfer some torque, but not all of it. If you're stuck well enough, you can spin two wheels indefinitely.

my rears have been wearing quicker than my front.. so it makes sense

my rears have been wearing quicker than my front.. so it makes sense

 

I don't think that's due to having a RWD dorifto machine... probably poor alignment or you just push it hard around corners.