So putting around town, I find my lockup engaging in 2nd and 3rd at low speeds to be very annoying, not to mention the fact that the shifts are pretty hard when the converter is locked up and I'm playing around in manual mode.

If I run a relay that cuts continuity to the TCC ground, and trigger the relay using the 4th gear wire from the transmission to the ecm, will this work as I think it will to keep the converter unlocked unless the 4th gear pressure switch in the transmission sees pressure?

I know the 4th gear pressure switch is NC and goes open when 4th gear is engaged (I think) so I know I would have to wire up the relays to cut the TCC ground when the relay loses ground from the 4th gear wire. Not a problem.

Bad idea? Seems like a simple fix that will let me keep automated 4th gear lockup while keeping her unlocked in 2nd and 3rd.



Thoughts?

 

Or you know, just put it in 3rd gear.

 

If I put it in 3rd, or 2nd, the ECM still triggers lockup once it's warm. That's the problem, when I'm being a hooligan and holding gears at low to part throttle, the TCC locks up and when I shift lets say from 1-2 or 2-3 it's very abrupt and feels like I'm abusing my mounts. I would like to keep the TCC unlocked unless it's in 4th. That way, If I do drive in D instead of OD, it will stay unlocked, but then I can pop up to OD and automatically get my lockup in 4th.

 

I didn't read the topic completely, so it sounded like the typical TCC locking/unlocking in traffic complaint. That condition is easily avoided by running in third gear. But anyway...

The TCC shouldn't lock in 2nd. I'd imagine you could prevent the TCC from locking in 3rd, by rigging the brake pedal circuit to fool the computer to unlock the converter. Or otherwise open the circuit when not in fourth, but I'm not too sure why a person would want to fool around with it. Seems the optimal balance of performance and longevity, etc is going to be obtained by letting the system work as designed. While I'm no expert on automatic transmissions, I'd assume running the converter unlocked would cause problems over time. I'm probably still missing something, so I defer to the experts.

 

No, No, No. All you should need is a diode. Of course, this depends on which way your transmission is wired. I bought mine from CraneCams. It is a short harness that connects inline at the trans connector. All there is a diode in there. It was made to delay lockup until 4th gear only. I will see if I can find anything. Either way, I still have mine and can dig it out.

 

if I put my shifter in D (3rd) or 2, the tcc will still lock up when cruising. So just shifting into 3rd is not an option, maybe on earlier years it was.

Interested in this diode mod.

 

One way to do this is to swap the 4th gear pressure switch out for a NO one. Then use that switch to provide the ground for the TCC solenoid. The solenoid ground is only connected to that switch, nothing else.

The power feed from the brake pedal switch to the trans remains as-is.

RBob.

 

I don't want to swap the pressure switch out, as that might confuse the ECM (not sure what impact that would have), but I should be able to use a 5 pin relay wired up so that when the ground signal is present (not in 4th gear) it interrupts the power to the TCC solenoid, and then when the ground is dropped (4th gear engaged) it applies power. Seems like a simple and straightforward thing, just want to make sure I am not overlooking something that will cause an issue.

 

I found the Crane Cams Transmission Lock-up Delay Performance Adapter. I had a friend take some pics which I will post later. I thought for sure there was only a diode in there, but without scraping the sealing compound off the 2? components in there, I can't tell for sure what the parts are. They may not even have part numbers on them. Looks like it might be a disc capacitor and something like a T03 case transistor (but it only has 2 leads).
This is probably going to bother me enough to remove the coating. It's not like I can't reseal it with Permatex or PlastiDip.


I did find the CARB EO for it on the internet: https://arb.parts/Executive-Order/D-225-45

 

Honestly, I am guessing that it has solid state (or at least miniaturized and compact) components that do exactly what I am planning to do with a relay It's a very simple solution, just put another piece of 'logic' in the TCC lockup that denies lockup, even if ECM triggered, unless the 4th gear switch sees pressure. A mechanical/electrical 'If/Then' function.

Thanks everyone. I'm going to do this, I'll report back when its done with some pics.

 

Here are the pics of the Crane Cams Transmission Lock-up Delay Performance Adapter #700:

 

It'd be interesting to know exactly what that device is and how it's setup. They used to be fairly common, at least in the sense that I remember them in the catalog. The description never said much about exactly what they're supposed to accomplish, and I didn't get the impression anyone ever actually bought one. It certainly wasn't in the mile long list of must do mods that used to be so popular in signatures around here. Can't find them listed anywhere now.

This is the one I remember specifically. I'm sure it's the same thing in a different packaging.

 

@ rbob , If the lo gear tcc lockup is set to a max value in $6e would this eliminate lockup in 3rd ?

 

I ordered a male and female 4-pin weatherpack pigtail, I'll make the relay in a removable section like the product above. Parts should be here Thursday Looking forward to trying this out this weekend. I might also put a low key 'lockup' indicator somewhere near the shifter since I could run the wire from my removable harness and not hack the factory harness. Would be cool if I could backlight the "automatic overdrive" emblem on the console when lockup comes on....

 

Most likely, along with preventing 2nd gear lockup. May also require an increase in the forced lock MPH parameter.

RBob.

 

I need to learn how to program..........