keeping you truck's 4l80E tcc locked while off gas

[c.w.barber]

I know this has been discussed before but has nobody figured out how to keep the TCC locked up when you lift your foot off the gas in the trucks?

[Atomic]

A guy on ls1tech did, its a simple hookup of a relay and turning off 2 codes. No segment swap needed....unfortunately he thinks his time is worth a lot more than anyone else that tried to figure something out and wants $20 for his instructions. If you search hard enough, I bet you could find it anyway...

[Vetal]

I can't make my 4l80 lock at all, it only did it twice and that's all, that was the only day it wanted to lock...

[gn2beatu]

If you could find a schematic to the wires on the tranny, I could do a PM on how to wire a relay to keep it locked. You could have a switch to enable the relay, wouldnt be hard. This would keep it locked all the time, so make sure there is no fluid path in your 1st gear or Reverse to accidently lock in. This would be nice for gas milleage especialy if you have a high stall converter. It would basicaly lock the second it hits second gear, and stay locked in 3rd and 4th. Turn off switch to disable. Any 12 volt relay would work. PM me @ TBSSowners.com if you need help as I wont be back in this thread, and dont come here much.

[gman4dx266]

The relays work the opposite than the 60e's to an extent. If you use reversing relays and a 60e tune, it will work. Look at how the 60 and the 80 use their solenoids to complete each shift, put them next to each other and you can rough out a schematic.

However, this should not even need to be done. This capability has got to be in the tune somewhere. I've heard of it being called coast delay, tcc decel lock, etc

[Vetal]

So far no one found it. So I'm thinking of manual TC lock switch but don't know whether 4L80 converter needs +12V or ground to lock

[turbo4.5]

Ground

[larboc1]

I've been wondering this too, glad i'm not alone.

FYI, in a '96 6.5 truck, if you hold the cruise control button down when you let off the pedal, the TCC stays locked in and it will stay locked in 4th down to like 35.

[Vetal]

Ground

thanx!

[Vetal]

Isn't it dangerous for PCM if I put ground on TCC pin when PCM doesn't expect it?

[midevil1]

Isn't it dangerous for PCM if I put ground on TCC pin when PCM doesn't expect it?

All the manufacturer's use a ground to signal for converter lock. You find the signal wire or the Lockup pin and wire in a toggle to ground. Been doing this in the diesel world for decades.

[Vetal]

OK, clear. I assume TCC solenoid doesn't get hurt from being 100% locked, not pulsed like in stock tune? I thought solenoids generally doesn't like to be 100% on due to overheating. Probably this one is liquid-cooled though?

[Frost]

This is no good if you already have a truck, but you if are MOVING to an 80 from a 60, this harness will let the 80 work with a 60 segment. http://www.tunedbyfrost.com/products_dev1.htm That means you get to keep cruise control, and lockup at zero throttle on the highway...

Alternately, you can DIY with two relays reversing logic as mentioned...

[oakley6575]

So If you know what ground wire controls the TCC, can you just hook a simple rocker switch to it? Just to use for the highway?

[Atomic]

Yes...but I would install some relays to have the computer control it automatically.

[oakley6575]

Why? if I only care about it locking on the highway, whats the benefit of having the computer control it? Will I hurt anything using the rocker switch?

[Atomic]

No, a manual switch is fine, but humans make mistakes more than computers do. Not that the consequences of human failure with a manual TCC switch are terrible, they arent, just its one less thing I would want to have to think about.

[oakley6575]

Would I run the signal wire from the rocker to the TCC SOL CTRL or the TCC PWM CTRL?

[Vetal]

I will try manual switch now, and then I think I'll go back to 4L60e tune. I can't live with TC locking only when TPS is 8% or more - for me it means big and usually violent drop of rpms. Also if I'm trying to not let off below 5%, I'm usually over speed limit

[Vetal]

Another reason for manual switch is to switch it early on cold start because I have to rev engine over 2000 just to get going, and I hate doing that on cold starts when it's 30F or less