Can i make the converter lockup manually? For whatever reason when its between 3rd and 4th around 2800 rpm this thing lays flat and locks up, when its cold it doesn't do it?

Mine's just the opposite. You have to pull the tranny to install a manual lock up but It's on my wish list.

http://www.atraonline.com/manuals/general/tetdv/tetdv-toc.htm
i keep this in my favorites. it tells you how to make several electronic trannys do whatever you want them to do. (for testing purposes anyway) it appears that terminal "s" on the tranny to a ground locks up torque converter.

CR from what I remember there is nothing out there for out vintage trucks, our TCC is PWM control not just an on off like in ealier 4L80-60, even commanded from a tech 2 it takes some finesse, couple of folks have tried some of the aftermarket controllers with mixed result and driveability issues. I think Howie E may have something on this in his web site, but I may be recalling something from the Diesel Page as well

So lockup is not effected by engine temperature? Then why does mine lock-up when hot, yet on a cold start and go, it won't lock for over a mile?

That is called 'emissions adherence', to which concept the PCM is programmed, and has been so since lock-up TCC's were first released.
Prevents noxious emission when loaded at below normal engine operating temps.

4L80E TCC is never fully applied - pressure is only applied sufficient to meet required torque input, via Pulse Width Modulation.

Enhancement requires PCM alteration, and still does not result in full lock-up, to protect hollow input shaft assembly.

Several products have been offered, mainly resulting in harsh shifting, which would indicate the product does not address PWM control.

Other products are offered, addressing point of lock-up, and demand lockup, relative to gear-range and vehicle speed.

And, yes - I designed an electronic switch-able PCM or manual-only version, allowing driver-demand PWM control.

But, why?

That hollow input shaft is the achilles heel, and Hydramatic Div was very well aware of that, imo - thus, the PWM concept.

The overdrive planetary is directly behind the TCC/pump, where reactionary forces from the transmission\drive train would be high.
Engine cranking at O\D rpm, while trans\drivetrain spins at final drive ratio

Normally, O\D would be on the transmission output shaft, with resultant lower reactionary force on the input assembly.

Re-flashed PCM programming handles it all very well, with no resultant damage, maintaining oem PWM control.

That's my story, and I'm stickin' to it........

OK, just for giggles i unplugged the coolant sensor on the x-over, idle kicked up a couple hundred, shifts 1st to 2nd @ 3000 rpm, 2nd to 3rd @ 3500 rpm but only when i let off will it make the 2-3 shift, won't shift to 4th no matter what and the convert doesn't lock-up at all. This sounds to me that with some tweaking in the PCM the shifting and lockup should be able to be changed, no?

No reason I can think of why your re-flash should not have increased transmission control required to handle the higher torque output...........

The 4L80E PWM TCC is THE after-market nemesis, for lock-up kits.

PWM is?

Pulse Width Modulated Torque Convertor Clutch - allows variable apply - nobody knows how to do it, viably, commercially.

after lookin at that site lupey posted, it kinda has me thinkin that you could lock it up manually real easy. the 4l80 for 93 and newer is on page 46-47.

Does that go for not locking it until after its in 4th? My 95 wouldn't lock until after it went into 4th.

Early models can be fooled/forced, OBDII with PWM controlled TCC no viable option found yet.

I will bring this up when i get my chip retuned (for free of course), maybe he has some ideas.

There should be some shift tune in there mine got it as part of the reflash., I don't know though about lock up though.

We didn't change any shift points when it was done as i was going back for a re-tune after hi-pops and shift kit were in and then we will put it on the dyno, i just want to get this damn air intake done before i go in.

the BD unit works great for me- it is NOT an automatic unit IMHO- flick the switch to lock it when you want to. Best use for me is when towing when speeds are between 40-50: drop into 3rd then lock it up, cuts out all shift busyness, keeps RPM up where I need them to minimize smoke, maximize driveability.

Now my wife borrowed it one day, and was *****ing to beat the band later about the lack of power and clouds of black smoke coming from the tail pipe when coming up the 8% grade to our house (it locked up from about 15 MPH and of course she floored it...)

Dslhead BD unit as far I I have heard does not work for OBDII PWM controlled transmissions.

ca '95-'96 GM deleted the 4L60E option with the 6.5L engines - 4L80E was optional '91 to that point.

1. On almost all GM Trans, TCC lock up is only allowed after Temp is above a set value

2. 95 and older (obd1 ) will work with an aftermarket " Torque-Loc" , allows manual control of TCC

3. There is a way of forcing TCC lock up on 96 and later by fooling
Trans to think a Overtemp has occured, But this will cause
" Hard Shifts( full pressure ) I use this method, but shift gears and lock TCC like a std shift, Do not load trans. when shift/lockup occurs.

I would like to be able to shift mine to 3rd, and flip a switch to lock up the converter, and unflip the switch when I had to slow down or wanted normal operation. Can this be done on a 99? How could you do it?

http://www.atraonline.com/manuals/general/tetdv/tetdv-toc.htm
i keep this in my favorites. it tells you how to make several electronic trannys do whatever you want them to do. (for testing purposes anyway) it appears that terminal "s" on the tranny to a ground locks up torque converter.
I read this when you posted it on the other forum. I guess I didn't snap to the lock up potential.

I talked to Joe Webb at Suncoast this weekend at the dyno event, might be a way to do it but according to him we will have to go into the tranny itself to make the change, said he needed to do some study on it, but as far as he knows no plug & play module for later vintage trucks.