TC Lockout??

[Marauderjack]

OK all of you computer wizards...... :)

I have asked this of all the "Tuner Guys" and nobody seems to know the answer??

Can somebody program our EEC to "UNLOCK" the TC in 4th gear when you turn the O/D switch "OFF"??? It seems that driving around with all 4 gears and no TC lockup would really be nice!! :cool:

The SCT guys programmed mine to not allow the TC lockup in 3rd at all and only in 4th at 50 MPH or above......Only trouble is that if I push the O/D "OFF" while on the gas the TC stays locked in 3rd until I let the car coast a second.....then it unlocks?? :confused: I don't know if this will hurt anything but I sure would like the switch to just unlock the TC and stay in 4th!! :beer:

Any ideas?? ;)

Marauderjack :D

[RoyLPita]

One of our members hardwired into the harness to do so but set off a code that triggered a check engine light. It is in a past thread somewhere.

Just my .02 and then some.

[cyclone03]

Short anwer is yes,the program can be adjusted to do what ever is required.

I have a PI 3000RPM converter and went the other way...
I do not want the converter to unlock in overdrive.Why? Because when the converter unlocks in OD the RPM rises and just seemed to slip the converter without any go.

My setup now shifts to OD at 42mph,locks the converter and it stays locked unless more than about 50% throttle or less than 35mph,then it down shifts to drive with the converter still locked,in a sense my car acts like a stick in 3rd and OD.

So if DR can do this with my car I'm sure you could go the other way.

[Marauderjack]

Well.......SUCCESS....FINALLY! !!

I had the damn TC disabled altogether in one of my SCT 9100 files and can drive in 4th gear without any goofyness and downshift to 3rd...or 2nd without the WOT "BOGGING" described in another thread!!! :banana:

Zack had mentioned that his car (like mine) was stronger at 3/4 to 7/8 throttle than WOT and as I thought it was the TC either trying to lockup or at "partial lock" as described by "trippletransam" in another thread!! When you back off of WOT it completely unlocks giving you the surge of power at less than WOT!!

I would suggest that any of you drag racers have one of your tuner files adusted to completely eliminate the TC and I think you will be pleasantly surprised with the results!!! :bows: WOT works like WOT should!!! :banana2:

Now back to the turn signals!!! :o

Marauderjack :beer:

[studio460]

I sure would like to understand this TC lock-up stuff better. Although I have the ability to adjust my TC lock-up in the SCT software, I have no idea how or where you do that. Also, anyone willing to write a brief tutorial on TC lock-up in general (what it is, how it works, why and how we would want to modify it) would sure get a lot of little "kudos" clicks from me! Triple-T? BillyG? Sarge? Anyone? Thanks.

[Marauderjack]

I would guess it is simply a way to get better fuel mileage?? :cool: When I go back to the "Stock" program it seems the TC even gets involved in 2nd gear....Partial lockup?? It locks in third and unlocks while coasting so as not to decelerate from engine drag......freewheeling to get better mileage?? :confused:

I drove around a bunch with no TC lockup at all and it is actually more fun and much more responsive!!! :banana: I think I'll take my tuner along on my next trip and see how the fuel mileage is affected without the locking TC at 75-80 MPH highway speeds.

We also wrote one file to move the TC lockup to 60 MPH in 4th only and it is very nice around town but allows for better economy on the highway!! :)

I repeat....All of you drag racers need to get hold of a file for your car eliminating the TC lockup!!! :beer: You won't believe the difference!!! :banana2:

Marauderjack.....with turn signals!!!! :bows: :banana:

[TripleTransAm]

When I go back to the "Stock" program it seems the TC even gets involved in 2nd gear....Partial lockup?? It locks in third and unlocks while coasting so as not to decelerate from engine drag......freewheeling to get better mileage?? :confused:



http://www.mercurymarauder.net/forums/showpost.php?p=124123&postcount=27

Yes, it's a partial lockup in 2nd gear (which, in my opinion, tears up the TC Clutch in a short while, which Ford addresses by recommending frequent tranny fluid changes to address the shuddering that develops at approx. 30000-35000 miles). I think I've seen 100% lockup in 2nd, but only when holding it in 2nd and reaching a much higher speed than it would see in normal driving in 'D'.

One reason that's been provided for this method of slippage in 2nd is to minimize the driveline roughness as the TCC applied... think of it as the difference between launching a manual tranny car by dropping the clutch or by slipping it... you will feel the clutch-drop much more than when the driver is slipping the clutch for a dozen seconds...

The freewheeling is intended for maximum mileage. Again, I feel this puts extra wear on the TCC with all the locking / unlocking going on (think of slipping a manual tranny clutch... same idea).

And best of all: let's say you're cruising at just over 40 mph and you depress the accelerator a bit for more oomph (passing etc.). You get a downshift and a little more pickup, right? Wrong. You STAY IN 4TH. What happens is the TCC gets partially released... so you're applying higher-than-average power output through a partially slipping TCC pushing a 4500 lb car through an overdrive gear! Yet more tearing up of the TC Clutch...


Yes you will feel slightly more acceleration keeping the TCC unlocked until the very last moment... it's a combination of a *small* amount of converter torque multiplication (there isn't much once you're approaching the stall speed of the converter) and the fact of the engine being at a higher RPM and hence developing more torque (due to the high-RPM nature of this motor). On my GTA, I get an increase in oomph once the TCC locks up in 3rd, since the engine really loves to tug at low RPM due to the tuned intake runners.

Keeping it unlocked through the whole 1/4 mile? I'm not entirely convinced this is the best way to go. There will always be a relative amount of TC slippage (ie. difference between input side and output side) if the TCC is unlocked, simply because there isn't a solid physical connection between the engine and the transmission (which is what the TCC provides, when 100% locked up). So those 20% losses that have been quoted as applicable to our MM's drivetrain will go out the window... use 25% or more, instead. Would be fun to get this confirmed on a dragstrip, using back-to-back runs.

And there is the issue of the tranny fluid and overheating... a torque converter that is not locked up will generate heat, lots of it, as the oil is sheared and whipped about inside the TC case. I mean, think about it... you're transmitting 300+ lb-ft of torque through a TC to get a 4500 lb car moving, and the only way to do this is via a FLUID! As your engine is revving at 2500+ RPM and your tranny input shaft is only seeing 1000 RPM, that's a lot of shearing... and even after the stall speed is reached and matched, not having a TCC engaged means that as your tach is reading, say, 4500 RPM, your tranny input shaft is still lagging at 4200 RPM, maybe less? Lots of shearing... lots and lots... and that generates lots of heat. Heat that this tranny wasn't designed to consistently deal with, since the designers were working under the assumption that the stock PCM programming would be in operation.

NBC, what in particular would you like to know about TCC lock ups?

[Marauderjack]

I don't know about the heat generated without the TC locking but I have to agree with Lidio.....It is a different car with the TC lockup set above 60 MPH in 4th only!!! :D

I had one file written to eliminate the TC lockup altogether for towing my small boat and will test that soon?? ;)

Since changing the files is only about a 5 minute operation you can eliminate the TC function for drag racing and switch back for the drive home......I cannot see how a 14 second blast down the track could generate enough heat to harm anything.....Oh Lidio.....Your input please?? :beer: Maybe someone can make back to back runs to see if it helps.....My SOP meter says YES!!!

I have an IR temp probe and will check trans fluid temps while I test with and without TC lockup.....Stay tuned!! :banana:

Marauderjack :bandit:

[Marauderjack]

TedS....

I have talked to Lidio at length and he said that he developed the program with the TC lockup above 60 several years ago and has had no fluid heating issues with any car he has done it on!! :bows:

I will keep an eye on it and if I need to increase the cooler size I will. The car performs so much better both around town and at WOT while passing....NO WOT BOGGING!! :banana:

What did manufacturers do about fluid heat before TC locking was started?? Heck I remember old Buicks that had one forward gear...."Fluid Drive" I think it was called?? Just a big TC with big fins?? :beer:

Marauderjack :beer:

[JohnE]

A locked convertor will transmit more power to the ground. If you unlock it, energy is lost in the form of heat. Of course the primary advantage of unlocking is to get torque multiplication and allow rpms rise (downshift), but then it should be relocked. There's a bit of misinformation being passed off here. The tranny shudder is related to partial locking of the tc and old broken down fluid. Heat breaks down the friction modifiers in the fluid and when they're gone, only a fluid change gets them back. FMC doesn't program a full lock of the tc, it's always commanded to have a low rpm slip for NHV reasons. This is why the stock tc lockup clutch has cooling grooves in it. After the fluild degrades and the clutches wear, they loose their effectiveness. Guess what, heat generation goes up and this wear situation progresses at a faster rate. Full lock of the tc, less time slipping to change gears and increased cooling capacity can make the fluid last longer. I've chosen to do these things and I change my fluid every 20k. Never had a hint of tranny troubles in 98k mi, even making twice the power the car started with. By the way, standard SCT tuning addresses the full lock and faster shifts.

If you want less fuss unlocking the tc on press of the go pedal, this can be done w/o always having the tc unlocked in 4th. Actually you can have the tc locked in cruising unlocked at medium acceleration and locked at WOT.

[TripleTransAm]

What did manufacturers do about fluid heat before TC locking was started?? Heck I remember old Buicks that had one forward gear...."Fluid Drive" I think it was called?? Just a big TC with big fins?? :beer:

The older transmissions probably didn't have to worry about using lightweight components, or paying close attention to cost-cutting. There is a reason why serious racers opt for the older 3-speed units for racing... most of the newer transmissions have more aggressive 1st gear ratios than the older ones, and the benefit of an overdrive 4th gear, so why wouldn't they want to stick with a newer transmission, right?

And in the ever-present need to cut costs nowadays, companies will search for any way to cheapen the components, aided by the ability of PCM programming to let them get away with things. 90s auto trannies all 'benefit' from reduced engine performance during an upshift (the famous torque management) which should bring about longer tranny life, but then this simply opens the door to cheapen it further, and then more PCM programming is adopted to deal with this, and so on... a vicious circle. (if you don't believe me, look at the cheap method of securing that drum - overdrive? - that occasionally breaks on our 4R70Ws... or allowing binding during a 3-4 upshift that would be destructive were it not for a pre-programmed soft upshift).

The old TCs (pre mid 60s) were not TCs. They were called fluid couplings... they used fluid to couple both sides of the unit. What makes a torque converter versus a fluid coupling is the presence of a 3rd element - the stator. The stator increases the angle of attack of the fluid at stall speed operation. ie. without the stator, the input side's fins whip the fluid onto the output side's fins, and this is what transmits engine torque to the transmission. (This is a simplified description... the coupling or converter is more like a donut and completely filled with fluid, so the 'whipping' of fluid is actually a constant circular flow within the unit, with both fins *really* close to each other... hence the increase in heat with the 'shearing', because the fluid won't flow cleanly from the input fins to the output fins because of their differences in speed).

The stator is a 3rd element with fins at a sharper angle than the other fins. When the input side is moving faster than the output side, the stator fins are at a perfect angle to increase the angle of attack of the fluid force and possibly the speed as well, not sure. This means that at stall speed, there is a torque multiplication that occurs. You get more torque out than the engine put in. You're still not moving the car at all (stall = engine moving at maximum speed such that tranny is at 0 RPM) so the whole conservation of energy thing is kept in check.

Once the two sides begin to match speeds, the stator actually gets 'in the way' since the fins are beginning to match up 1:1 (close to it, never perfect). So fluid actually begins to hit the back of the stator fins, so to prevent the fluid actually trying to slow the unit down by this action, the stator freewheels when being acted on in this reverse manner. So it's like the stator isn't really there anymore.

The old old fluid couplings were probably tighter than the post-mid-60s converter, because I've read about how those old transmissions took forever to shift because "the couplings had to dump and refill". I never understood that comment, and I wonder if this dumping had to do with allowing smooth tranny shifts, as well as perhaps requiring such dumping at idle to prevent holding the engine down too low and stalling it. Can anyone shed light on this for me?

I guess there's a reason after all as to why they called it a 'slushbox'? ;)


I've been way tempted for a while to address my PCM programming in order to maximize tranny life. The thing that's held me back is that I wonder if I would be uncovering some other weak area... for example, I'd love to keep the TCC locked up on deceleration (as on my GTA, I love it), but then I wonder if this will impose reverse-torque shocks on the overdrive components and help bring about some C-clip related problems...