TCC Locking

[GMPX]

Hey Trans guys......

I have noticed all the Holden calibrations have the TCC lock during shift disabled, a few people asked us to include that option because the like to force it to lock on upshifts.

My question is, what affect does this have during at part throttle and WOT?
What about TCC or general transmission durability?.

Cheers,
Ross (who knows very little about the inside of a 4L60E).

[joecar]

Usually the TCC is disabled momentarily during a shift so the convertor can slip and "soak up"
the momentary difference in RPM between engine and trans at the start of the shift;

At the end of the shift, the convertor is slipping and multiplying torque, and since the
engine RPM has dropped, the the slip/multiply avoids bogging down the engine
(the convertor multiplies torque (upto x2.5 approx) whenever it slips while being driven);

If the TCC remains locked during the shift:
a. the springs on the TC clutch plate may get overstressed (the TC clutch plate looks/behaves the same as a manual trans. clutch plate);
b. the RPM difference must be soaked up by the apply components inside the trans, resulting, over time, in burnt/broken band/clutches;

At light throttle, a. and b. would not as severe as at WOT, and at higher throttle a. and b. would be very severe if torque management was disabled.

In the short term, keeping the TCC locked may improve 1/4 mile times (but not necessarily so since the slipping TC multiplies the engine torque into trans.).

[Delco]

In the short term, keeping the TCC locked may improve 1/4 mile times (but not necessarily so since the slipping TC multiplies the engine torque into trans.).

Cant even see it helping there either as the TCC should never be locked during WOT as the TCC clutches dont like it

[joecar]

In the short term, keeping the TCC locked may improve 1/4 mile times (but not necessarily so since the slipping TC multiplies the engine torque into trans.).

Cant even see it helping there either as the TCC should never be locked during WOT as the TCC clutches dont like it

Yes, the TCC consists of only one friction surface and one plate surface.

[GMPX]

O.K, so it's pretty much a case of 'maybe' good to shave a few tenths off the 1/4, but not really a good thing to do.

Cheers,
Ross

[Tre-Cool]

Digging up an old thread, but for the past 8 months i have had tcc stay locked during shifts in the A6 with out a problem.

It's much more noticable once you have a stall and seeing as i really only use the lockup between 5th,6th gear there really is no jerking going on as it is only locking at low TPS.

Though i have been playing with lock up from 3rd gear and you do get the hard shift into 4th gear. Almost feels like a manual gearbox.

[oztracktuning]

So 5 to 6 is nice? I have mine commanded to only lock in 6th in drive. Maybe command 5th and let it stay locked by the sounds of it. Good work.

Make sure you change the WOT lockup settings in 4th so it doesnt lock. Factory thats how they are set.

[Tre-Cool]

with lockup on in 5th, then when 6th comes in your only dropping about 800rpm'ish so yeah there is no jerky hurky. ya just see the revs drop and thats it.

though im talking about speeds of about 90-110kph here.

i loaded a tune in the car last night to pretty much eliminate the use of 3rd gear at anything below 70% throttle aswell, now it goes from 2nd to 4th.

which is great for me. 3rd gear is prety pointless i reakon because 3,4th are so close togethor in ratio's and with the stall i can let it "slip" before locking tcc back in.

i just have to re-adjust the 100% tps kickdown speeds. Though personally i dont do it, as i go manual mode. I figure it wouldnt hurt to get it to drop from 6th to 4th only and ride the stall.

[zrx1200]

with the a6 can we teach it to stay locked ?
as a recent trip down south towing the gbox would stay in 6 tq unlocked at 2000 rpm."fish n chip time"
yet if the road changed it would select 5th and run lockup at the same rpm.
or 6th at 1500 rpm
is there anyway we can use the a6 in auto and limit how high a gear it can change.like the a4 select 3 and still have auto.?
yes i realise you can drive it manually ,

[Tre-Cool]

anything can be done. just depends on how you setup your gear apply,releases and your tcc lockup/release speeds.

I work off the theory that if your running in 6th gear then you want lockup all the time(below 25%tps anyway) so my tcc apply speeds match my 6th gear speeds. then tcc release speeds are just below the 5th gear apply speeds.

a neat little trick i have found to work great is for say 31.25% tps and higher you bring up the release speeds (105kph+). this way if you have a stall convertor like i do you can stay in 6th gear and bring the rpm up for over taking & torque multiplication.