Transgo Kit Guinea Pig!!!

[lieutenantcolumbo]

Well, I called Transgo today and they said that the Legacy kit was put on the back burner and will not be ready for 2-3 more months!!!!

 

AHHHHH!

 

I really wanted this kit before the autocross season started back up.

 

 

 

Looks like I get to maintain my exclusivity a little while longer.

 

Just about a year w/ my TransGo kit (along with a total rebuild..see 5EAT Pride! thread) and no problems to report. I'll probably do a drain and fill in a couple weeks just to see how the fluid is holding up.

[ClimberDHexMods]

Curious to see if the 5EAT has lock up solenoids -

 

If so, is the tranny strong enough to sustain a locked shift (this creating less heat and band wear) and not grenade the internals due to the shift-shock?

 

All you would have to do to find that is read the factory service manual. Keeping the TCC locked up during shifts sounds like a really bad idea.

[DrSpeed]

We have our truck transmissions that shift with the TC locked....how is that a bad idea?

 

No slip, no heat, bang, into gear.

[ClimberDHexMods]

The bang is what worries me. The unlocked TC is what allows all the actual planetary gear sets (and the engine) to be isolated from any major forces, since there is a lot less inertia on the trans input shaft. Something would have to give, and I don't think it would be the 4 tires. The clutch packs are already prone to burning.

 

That said, what are the details of you doing it on your truck? What controls it? Please divulge

 

To answer your question, it's PWM 700hz single solenoid on the TCC.

[underground000]

You guys that are really interested in this. Have you gone to their shop and asked them if they would do it instead of calling them and waiting for a response.

 

Just a suggestion since you are dealing with them indirectly on the phone.

[fishbone]

We have our truck transmissions that shift with the TC locked....how is that a bad idea?

 

No slip, no heat, bang, into gear.

Your truck transmission and the Subaru drivetrain have absolutely nothing in common. If you put full load on that truck and haul it like that, I am sure you will wreck the tranny.

Also, when the TC is unlocked, it multiplies torque. How is that a bad idea Sure, at the expense of hp, but what that means is it runs hard on the street and loses the edge on the freeway. I have won many races at the drag strip against higher hp cars simply because the high torque down low launched the car and they were never able to catch up.

A locked up TC punches the clutches because there is no hydraulic flexibility. You don't feel it in the truck, but we feel it in the Legacy.

As a compromise, I would say a much better idea would be a very low stall torque converter, something to the tune of 1600rpms or less instead of the stock 3400-3500.

[tangcla]

That is a programatic issue, not a mechanical issue.

 

What about when you shift from N to D (or N to R), and there's a one-second delay before the accelerator does anything? Is this electronic or physical delay?

[fishbone]

It is mechanical and as long as it does not take more than 2 seconds, it is normal behavior. The diagnostics manual states going to D should take about 1 second, going to R should take about 1.5 seconds.

You should not have the foot off the brake until you feel that the transmission has engaged.

Pretty much every automatic transmission has that delay. If it takes longer, it usually indicates worn clutches, bands or sticking solenoids in the valve body, possibly blocked passages or abnormally low line pressure (possibily due to a clogged filter, ATF low, etc) or ATF in very poor condition.

[tangcla]

Ok, thanks fishbone

[DrSpeed]

Wow, at that rate, why not make it a complete manual valve body?

[ClimberDHexMods]

It is mechanical and as long as it does not take more than 2 seconds, it is normal behavior. The diagnostics manual states going to D should take about 1 second, going to R should take about 1.5 seconds.

You should not have the foot off the brake until you feel that the transmission has engaged.

Pretty much every automatic transmission has that delay. If it takes longer, it usually indicates worn clutches, bands or sticking solenoids in the valve body, possibly blocked passages or abnormally low line pressure (possibily due to a clogged filter, ATF low, etc) or ATF in very poor condition.

 

No, not just mechanical. The shift lever movements from P to R to N to D do actuate mechanical (actually hydraulic, same difference) engagement in the transmission, causing P/N, R, D to engage, etc. But there is also a lot of electrical solenoid activation taking place on top of this.

 

There is an electronic switch communicated to the ECU from the TCU telling the engine to make zero power (close electronic throttle) until the shift to or from P / R / N / D is complete. That way when rushed soccer mom floors the gas the same instant she puts the trans into D, the car doesn't take a beating.

[tangcla]

Interesting ClimberD - also interesting that you CAN slap it from N to D still though

[ClimberDHexMods]

Interesting ClimberD - also interesting that you CAN slap it from N to D still though

 

I rev'd and slapped it into D exactly once, and will never do it again Since the engagement is mechanical, there is nothing electronic to prevent it. I have not and will not do any testing on this. Only person going to screw up this now is the valet.

[tangcla]

I know. I swear, it was entirely accidental.

 

Having said that, I've noticed a few times while I was driving today, some pretty bad drivetrain shock when it upshifts as I back off the throttle - this is bad? Or normal?

[ClimberDHexMods]

I know. I swear, it was entirely accidental.

 

Having said that, I've noticed a few times while I was driving today, some pretty bad drivetrain shock when it upshifts as I back off the throttle - this is bad? Or normal?

 

It should NEVER produce shift shock. If it is, especially limited to a specific shift, then the only way around it is to shift when accelerating. But that is not very convenient.

[fishbone]

There is an electronic switch communicated to the ECU from the TCU telling the engine to make zero power (close electronic throttle) until the shift to or from P / R / N / D is complete. That way when rushed soccer mom floors the gas the same instant she puts the trans into D, the car doesn't take a beating.

Thanks for that tidbit. I am ashamed to admit I was in a hurry more than one time and even though the tranny completely engaged in gear while I was a full stop, I immediately got on the gas only to not have any power whatsoever for a second. Now I know why.

[ClimberDHexMods]

http://files.sharenator.com/a_shame_Most_Random_Flash_Ever-s403x338-80052-580.jpg

[DrSpeed]

The bang is what worries me. The unlocked TC is what allows all the actual planetary gear sets (and the engine) to be isolated from any major forces, since there is a lot less inertia on the trans input shaft. Something would have to give, and I don't think it would be the 4 tires. The clutch packs are already prone to burning.

 

That said, what are the details of you doing it on your truck? What controls it? Please divulge

 

 

The 48RE is a four speed fully automatic transmissions with an electronic governor. The 48RE is equipped with a lock-up clutch in the torque converter. First through third gear ranges are provided by the clutches, bands, overrunning clutch, and planetary gear sets in the transmission. Fourth gear range is provided by the overdrive unit that contains an overdrive clutch, direct clutch, planetary gear set, and overrunning clutch.

 

The transmission contains a front, rear, and direct clutch which function as the input driving components. It also contains the kickdown (front) and the low/reverse (rear) bands which, along with the overrunning clutch and overdrive clutch, serve as the holding components. The driving and holding components combine to select the necessary planetary gear components, in the front, rear, or overdrive planetary gear set, transfer the engine power from the input shaft through to the output shaft.

 

Built Transmissions are capable of handling 800hp and 1200 ft-lbs full throttle shifts without commanding defueling (torque management) from the engine.

 

Granted this is a larger transmission, more aggressive clutches, and billet goodies (input, intermediate, output, flex plate), and a triple disc converter.

[ClimberDHexMods]

Sweet; how does the defueling logic work? Straight injector cut on X out of 10 cylinders? Because I could definitely replicate that on the Legacy...

The 48RE sounds like an absolute beast when built. I would love to pull off WOT shifts with no TCC disengagement or torque down. And at $500 per rebuild kit and a spare parts tranny, I could maybe swing finding out.

 

What controller runs the aftermarket shift and TCC logic? Or is it through writing to the stock TCU?

[DrSpeed]

A beast? Yes.

 

Idestrucable? No. =)

 

No 10 cyl diesel here...6 (Cummins) or 8 (Powerstroke/Duramax).

 

2 options for control: program through PCM, or standalone controller (with feed-forward to engine).

 

The standalone is the best option:

 

http://www.powertraincontrolsolutions.com/miltrans.php

[ClimberDHexMods]

A beast? Yes.

 

Idestrucable? No. =)

 

No 10 cyl diesel here...6 (Cummins) or 8 (Powerstroke/Duramax).

 

2 options for control: program through PCM, or standalone controller (with feed-forward to engine).

 

The standalone is the best option:

 

http://www.powertraincontrolsolutions.com/miltrans.php

 

I am familiar with the PCS controller, but what does "feed-forward to engine" mean and how do you set the PCS controller to output it?

 

Edit: I just did a little Googling, and I am still at a loss for the best way to cause the stock ECU to temporarily drop power. Messing with any ECU system appears to have drawbacks, whether it be timing, fuel, boost or airflow.

[DrSpeed]

The factory programing for the Cummins does the same as the Subie - when it's about to shift, it knows it going to unlock the trans, and sends a message to the engine saying "time to shift, cut fuel and time for a split second". As the shift is complete, it tells the engine "okay, balls to the wall" again.

 

This is function of road speed, engine speed, and ramp up of APPS (accelerator pedal position sensor) voltage.

[ClimberDHexMods]

I like the Cummins approach.

 

The Subi just pulls timing during a shift. A LOT of timing. I have seen negative single digit timing numbers on WOT shifts.

 

I considered accelerator position sensor trick wiring as a way to cut shift torque, but the PCS shift map would be based off of TPS, and cutting APPS would throw a wrench in it.

Boost dump still reigns as the only good approach I can come up with, short of plumbing a second throttle body in series with the incoming air in order to accomplish the same end of less actual airflow... haven't looked into how the boost control or MAF logic will respond to all this yet. And I can't do switch override of fuel injector current because there's a 1 in 2-3 chance per cylinder cut that the switch will deactivate or reactivate during an ECU spray ON moment, causing insufficient fuel spray and a probable lean condition. Not sure what that would affect...

[DrSpeed]

That's the one benefit with the diesels....you have a LOT of latitude with the a/f ratio.

 

It inherently runs lean, so knocking is not a big deal. You basically add the minimal amount of fuel to keep the engine running....and when it goes rich, you'll either make smoke or flood the motor (which is bad, as it hydrolocks the sumbich),

 

Timing is the only thing you can really do with the gas pots...but what about making stronger parts? Billet goodies?

[ClimberDHexMods]

That's the one benefit with the diesels....you have a LOT of latitude with the a/f ratio.

 

It inherently runs lean, so knocking is not a big deal. You basically add the minimal amount of fuel to keep the engine running....and when it goes rich, you'll either make smoke or flood the motor (which is bad, as it hydrolocks the sumbich),

 

Timing is the only thing you can really do with the gas pots...but what about making stronger parts? Billet goodies?

 

Well... I like the idea of stronger parts and more clutches in each pack, that kind of thing. So far no one has actually broken anything inside a RE5R05A or Subaru 5eat variant, as far as I can tell. The exception is the center diff, but those only really break during launches. Frank_ster beefed up the planet bearings in his center diff with solid brass ones instead of the stock needle bearings, and he has had no problems with anything breaking since. However, he also hasn't done a harsh launch with the car since he made the upgrade. So time will tell with that.

Anyways, back to topic, there are no billet parts available for the RE5R05A that I have seen, and I'm not sure they would really be that beneficial anyways, since nothing has broken yet. IPT supposedly cryo treats all the moving parts in the trans, which supposedly makes them a lot harder.

One reason things don't break may be because the clutch packs are designed around a 300tq engine, and our particular trans control is tuned for a 250tq engine with turbo boost threshold considerations. So instead of the stress going into a solid part and breaking it, the clutches instead just slip.

To be able to hold 450ctq through a shift, the clutch packs would need to be beefed up with more clutches, thinner steels, more line pressure, faster engagement, and that may or may not show us the limits of the stock internals.

It's uncharted territory for the most part. The turbo 350Z guys don't seem to have the problems we do (no center diff) but that isn't quite apples to apples.