Getting 4EAT to lock torque converter in 2nd and 3rd

[91Beater]

I can only get it to lock in 4th.

But from what I read, it should lock all but 1st gear.

"The 4EAT Transmission is a 4 speed, microprocessor-controlled transmission
that was first introduced in 1987.5 Subaru models. It is not a 3 speed transmission
with overdrive. It features a lock-up
torque converter which locks up in all forward gears
except 1st. It has been offered in FWD or Full Time
AWD configurations."

Is there something wrong with mine ? Does yours lock in 2nd or 3rd?

[James614]

I'm pretty sure the 1st Gen Legacy only locks in 4th. Other applications lock in 2nd and 3rd, but the only one I know for sure is the overseas Legacy Twin-Turbo. Swapping TCU's might do it, but there's electronic/signal differences to look out for, even if they are pin-compatible.

Oh yeah, there's been talk on the Ultimate Subaru Message Board, as well as the SVX forums, about rom-tuning the TCU. If you can find whoever knows how to tune these TCU's having them program it to give you 2nd and 3rd lockup should be no problem.

[Legacy777]

The torque converter will partially lock in the lower gears, as such, you will probably not notice it. Also, the TCU likes to upshift all the way to 4th gear even at low speeds ~25mph. So the chances of you just cruising around in 2 or 3 and have the torque converter fully lock is very slim.

Plus if you manually keep the gear selector in 2 or 3, the revs and throttle input will be such that the torque converter won't lock.

[Alphius]

The TCU will lock the torque converter in 3 for sure and maybe 2 as well in regular driving in D, however putting the stick in 2 or 3 will prevent it from commanding a lock.

[91Beater]

The TCU will lock the torque converter in 3 for sure and maybe 2 as well in regular driving in D, however putting the stick in 2 or 3 will prevent it from commanding a lock.

You can check if the torque converter is locked by lightly feathering on the throttle. You know its not locked when the RPM floats up indicating a slip.

This is where it says 4EAT locks in all but 1.
http://www.northursalia.com/techdocs/pd ... n/4eat.pdf

Using my method, I can only get it to lock in 4th and only above 45mph or so.

If the transmission is staying in 2 or 3 with the selector in D, the load is high enough that I don't see how it will lock.

[James614]

Yeah I've never once been able to get mine locked below 45 in 4th, and I've tried and tried in the past desperately seeking better economy. 2nd and 3rd locked would require locking at much lower speeds.

I've read posts on a UK Legacy forum were guys were saying their BD Legacies felt like they had "way more than 4" gears due to the lockup behavior. No auto US Subie I've driven has behaved anything like that, although I know of several other makes' newer vehicles that do.

Really ashame because these cars have the torque to pull from much lower rpms under much higher loads than the trans allows currently, and as it is they sacrafice a good deal of fuel economy because of it. The power mode negates the need for a performance-biased standard programming.

[beatersubi]

I wonder how hard it would be to tap into the TC lock signal and install a manual switch.

[James614]

Not hard at all. I looked into this, but determined it would be a novelty more than anything else and largely impractical (non-intuitive) to operate consistently. Maybe if the switch was foot-operated it'd be easier. But without also controlling shift points I can't imagine the locking behavior working as well as you'd want in that situation.

[beatersubi]

I'm almost surprised that it hasn't been done on the USMB. It would be nice to hear first-hand what the driving characteristics are like with it manually locked.

[Alphius]

Both my girlfriend's '98 Outback 4EAT and my '92 Touring Wagon 4EAT would detectably lock in 3rd. The only reason I am not definite on the 2nd gear TC lock is because I never felt it myself but theoretically it should be possible.

My girlfriend's Outback will lock in 4th at light throttle around 43-44 mph and stay locked pretty aggressively and third will lock from about 31 mph but it will unlock very easily for better torque multiplication.

[James614]

Now that I think about it, my wife's 91 FWD N/A (RIP) locked much more aggressively and at lower speeds than either my old '93 N/A and my current '93 TW, but being her girly car with tinkerbell seat covers I didn't take the time to become intimately familiar with it. And I remember reading an entry from some manual stating differences in the trans programming over the years (within the first generation). But the '91 DEFINITELY have different shift/lockup programming than either of my '93s, and this was before I began trying to barbeque my trans on a semi-daily basis So the difference wasn't attributable to wear.

Sad that every first gen I've owned/driven has been an auto!