Manual Lock Up Switch, with relays

[sag2]

I installed this lock up switch today and it works great. It is much better than just a switch as it locks up with the switch, but cancels with the brake input, and lets the PCM take over if it meets the normal criteria for lockup. I used mini relays, but it would work with any ISO relays. I would also like to add a pressure switch in the governor port that would prevent an accidental lock up when stopped, or kill the lockup below the pressure set of the switch. I added the LED so I would know when the TC is manually locked. When the PCM takes over, the LED goes out.

 

[sag2]

OK, I'll explain the operation for some clarity.
Looking on the diagram the relays are numbered from left to right, 2 (Torque converter), 4 (PCM), 1 (Latching), and 3 (Brake).

When you want to lock up the converter you press the push button. That latches relay 1, and also powers relay 2. Relay 2 now grounds the torque converter solenoid in the transmission. The converter is now locked up. The LED also lights and stays lit. If you step on the brake, relay 3 turns on, and pulls the power from the ignition feed. If you are locked up, say in fourth gear at 35 mph and you accelerate to 50 mph, as the PCM grounds the circuit to relay 4, relay 4 then pulls the ground path to relay 1 and the PCM is now in control of the converter. The LED also turns off.

 

[WCPoe]

What a great idea. Oo. Sure beats buying one of those $500 convertor lockup controllers from one of the overpriced aftermarket folks. Thanks for taking the time to design, build, test and sharing this. Maybe you should have applied for patent before you posted because I'm sure one of the "prominent aftermarket" companies will steal the idea.

Oh yeah, thanks for all the help you provide. Have a Happy New Year.

 

[p-Bar]

Sag Don't see your 33 ohm resistor to ground . I was planning on doing the lock up switch as my trans was rebuilt with some Goerand goodies and rebuilder ran me up a wire for it. Also the pressure switch at the gov solenoid would that also act as low MPH to disingage? Thanks

 

[sag2]

Oops, your correct. I didn't use 33 ohm as when I did in testing the voltage was still 4. 5 volts on the solenoid wire with the switch on. When the PCM grounds the solenoid the voltage is approx . 8 volts, so I used a 10 ohm and it got me just about perfect. Just for info, the solenoid has 33 ohms of resistance across the coil.

 

[DaveHess]

Where is the 10 ohm resistor in the wiring diagram and which truck did you install this on?

 

[sag2]

Looking at the diagram, the number 2 relay on the left. It is between the splice between the number 2 and number 4 relay and the normally open contact of relay number 2. That way it only adds resistance to the circuit when relay 2 is on with the push button switch.
Put it on my father in laws 91 Dakota.

 

[p-Bar]

Hey Sag been messing with the lock up switch very interesting if I have the truck in drive and activate lock up it goes into O/D and locks up . If I push in the tow haul button and activate the lock up it goes into third and locks up . if I manually pull it down into second and activate lock up it will lock up . Very unique.

 

[SDrake]

I have been using similar setup for about a year and have lately been thinking I need to post info on this. It provides a fantastic improvement in managing transmission fluid temps in city and hilly towing and on and on. My setup uses only 3 relays and I have the pressure port switch and a second switch momentary off switch in series with it to kill the whole thing in the event I don't want manual lockup. That switch is doing what yours is doing with the brake switch. I haven't analyzed your circuit to see what happens different functionally from what my set up is doing. I haven't ever posted pics on forum before but I lately have figured how to scan from my new printer/copier/scaner to a file so perhaps this is the time to try something. I have felt guilty not saying anything about how fantastic this set up is but did not know how to convey the needed information so I just kept my mouth shut.

A transmission guy one day at the prison school showed me the pressure port to tap into so I just applied my Navy electronics technician background to come up with the relays lash up. Since then I have seen the circuit in various radio hookup sites.

My real purpose in speaking up at this time is to encourage any of you inclined to do so to take the initiave and get this thing done. It can be a real transmission saver in the hands of someone who knows how to manage the stresses in the transmission. Others do this for performance reasons and so it also gives you a good way to tear your transmission up if you want to do that I surprised the dickens out of a guy in a dodge 1500 hemi a few days ago by using lockup in second and doing a little speed shifting out of lockup and quickly back into lockup into third and fourth. He probably I had a souped up engine and never realized I was just smarterThe whole time he was trying to catch up with me I could hear his engine just roaring out of lockup and getting nowhere.

 

[p-Bar]

Thanks for posting Sdrake look forward to the pic of your circuit too. The lockup is amazing

 

[sag2]

Hey Sag been messing with the lock up switch very interesting if I have the truck in drive and activate lock up it goes into O/D and locks up . If I push in the tow haul button and activate the lock up it goes into third and locks up . if I manually pull it down into second and activate lock up it will lock up . Very unique.

First off, if you just cut the TCC control wire at the PCM and ground it while in 3rd or 4th, does it lock up? Just run a jumper wire from under hood inside the cab and touch it to a good ground.

 

[ScottLewis]

This thread intrigues me since I've wished for better control over the lockup for a long time. As you're aware, the '06 has somewhat different ECM control of the lockup because of the Jake brake. Would adding this manual lockup have any negative impact on that?

 

[SDrake]

On edit, was responding to sag2 and danavilla posted in the meantime. To sag2, Yes, cut it if you do not want the PCM to have control, otherwise just tap into it and ground it when ever you want lock up in 2, 3 or 4. All the PCM does is take that wire to ground. I am not sure about first. Before I put in my safe system, I threw the switch one day while sitting still and idling in park, and the converter locked hard and stalled the engine when I put it in drive, so something hydraulically happens to the gear servos as well (may have been on my 94) Any way I don't want to ever try lockup in first until I know whether that much torque can be handled. I even wonder about second. never lock up second except in a smooth shift and then get on it as needed to get up a grade.

The thing that most energized me to come up with the circuit I am using is that on my 94 my wife took to using my truck to take the grand children on some outings and they would play with the toggle switch I had tucked between seat. After a couple of calls from my wife about something happening to the truck, "it just bucks and jumps and almost ran into a tree," I researched the pressure switch. Now the converter cannot lock below 25mph (where I set it)and I am relieved of having to remember to take it out of lockup as I slow down and the circuit resets and is dead until a switch is pushed above that speed. The grand kids can play with them all they want, not that that is allowed to happen. They got so spooked at what happened to grandma when they messed with the switch, I hear them correcting each other when they are in a car, "don't touch that switch. " Well if the devil makes one of them mess with my lock up switch they are going to be disappointed. One of them, a 7 year old mechanically curious boy, caught on and mischievously pushed the switch while I was driving so I had to explained a few facts of life to him

I am looking for my sketch and the part number for the pressure transducer so I can post. I just saw it last week somewhere, humm.

 

[sag2]

To answer two questions, yes the lock up control is somewhat different on the late trucks. It is not grounded, but pulse width modulated to ground so it is difficult if not impossible to duplicate what the PCM does to control it.
Second is you really do not want to shift it locked up if possible as it is very hard on the internals. The factory unlocks the converter on shifts to soften the shift.
I would like to know the PN of the pressure switch. I looked but could not find one that was/could be set to about 20 PSI. Lots of them at 5-10 PSI, but that seemed too low for my liking.

 

[SDrake]

Yep just as I pushed the post button I realized my answer did not apply to late level trucks but then I said to self, my signature is posted and someone will correct this before any harm is done. I have seen posts where someone seems to think that it matters where along a wire you tap into it and I was just saying go for it up at the ecm if that is more convenient.

The pn for the switch I used is Suco 0166-40504-1-020 Pressure Switch. I googled to find it when I bought it. . price was about $25. Still working on the sketch. One thing I like about my lock up is that if I leave it on it forces staying in forth which is often what I want to happen when reaching a borderline downshift situation such as cresting a long interstate pull and speed has slowed to where the cruise is about to force a down shift. You mentioned that the four relay circuit drops out when the ecm goes to ground. Sometimes that would be nice. Just have to decide what you really want.

 

[ScottLewis]

Keeping it in fourth at slightly lower speeds than stock would be of benefit for sure as I often feel running at 35 or 40mph in third is reving higher than needed but the stock transmission won't shift up until closer to 45. Another wish is for lockup to hold down closer to 20 mph or even less so the exhaust brake would work at lower speeds, even in first or second. I just don't know if that might cause transmission problems

 

[p-Bar]

Keeping it in fourth at slightly lower speeds than stock would be of benefit for sure as I often feel running at 35 or 40mph in third is reving higher than needed but the stock transmission won't shift up until closer to 45. Another wish is for lockup to hold down closer to 20 mph or even less so the exhaust brake would work at lower speeds, even in first or second. I just don't know if that might cause transmission problems

Dan I found that running in third gear at the speed you are talking crates better MPG (I am using a Scan guage II so I can monitor real time) It lugs a little too much in fourth and I think thats hard on the thrust bearings too. Lock up at 20mph is possible but you will need to manually pull it down to 2nd and first otherwise it stays in third and wants to kill the engine. Sag I contacted the company in regards to the pressure switch assume we want normally open? and would place it where you have the stop lamp switch?

 

[p-Bar]

Hey guys I contacted a dist for the pressure switches . We need to buy three but we get a break it will take about 4 weeks I can head this up you will have to pay me for the part and shipping to your location so if you are in let me know I will put the order together. if you reneg on the deal i will find you and... ... .

Note: This estimate is valid for 30 days from the date shown below.
Prices quoted are for quantities shown. Stock is subject to prior sale.
MTO quantities considered complete 10% under/over unless noted.

Quote Information
-------------------------------------------------------------------------
Customer PO#: SUCO SWITCH Quote Number: CA05-376618
Release No: Date: 03/25/2013
F. O. B:
Terms: . CRDTCD
Delivery: STOCK UNLESS NOTED


Qty Description

3. 0 SUCO 0166-40504-3-020 PRESSURE SWITCH
Item No... ... ... . : 99999999
Cust Stk No ..... :
Price... ... ... ... : 31. 430 94. 29
Delivery Date ... : 04/19/2013

HAVE TO MEET MINIMUM SO THREE AT 31. 43 OR 2 AT 35. 71
4 WEEKS TO SHIP


2. 0 SUCO 0166-40504-3-020
Item No... ... ... . : 99999999
Cust Stk No ..... :
Price... ... ... ... : 35. 710 71. 42
Delivery Date ... : 04/19/2013




SUBTOTAL 165. 71
FREIGHT* 0. 00
TAX 13. 25
TOTAL** 178. 96

 

[Mobius1]

Is it too late to get in on this? I am very interested in this

 

[p-Bar]

Mobius no one has hit me up on this . I will put you on the list