How to control 47Rh lock up with a pressure switch?
#3005302
01/14/22 04:53 PM
01/14/22 04:53 PM
|
Joined: Jan 2003
Posts: 7,495 Minnesota
Hemi_Joel
OP
master
|
OP
master
Joined: Jan 2003
Posts: 7,495
Minnesota
|
Hi, I recently swapped a 47rh transmission into my '93 Dodge 1 ton, behind the Cummins. So now I have a lockup torque converter. I am operating it with a toggle switch on the dash. I thought that would be no problem but I ran into a situation where it was. Somebody pulled out on me when I was doing about 60 MPH and I had to do a panic stop. Jamming the brakes, steering the truck, just paying attention to what was going on, I didn't hit the switch to unlock the converter and it pulled the motor way down. It was like driving a manual transmission truck and not stepping on the clutch. I have heard that there is a way to wire a pressure switch in series with the toggle switch so that the torque converter will unlock at a certain mile per hour. Can anyone clue me in on what switch to get, and where to screw it into the transmission? Thanks, Joel
[img]http://i.imgur.com/boeexFms.jpg[/img]31 Plymouth Coupe, 392 Hemi, T56 magnum RS23J71 RS27J77 RP23J71 RO23J71 WM21J8A I don't regret the things I've done. I only regret the things I didn't do. "Wise men talk because they have something to say; fools because they have to say something. ~ Plato"
|
|
|
Re: How to control 47Rh lock up with a pressure switch?
[Re: Hemi_Joel]
#3005325
01/14/22 06:45 PM
01/14/22 06:45 PM
|
Joined: Dec 2009
Posts: 20,647 in a cattle trailer down by th...
Guitar Jones
Paddle faster! I hear banjo music!
|
Paddle faster! I hear banjo music!
Joined: Dec 2009
Posts: 20,647
in a cattle trailer down by th...
|
Hi, I recently swapped a 47rh transmission into my '93 Dodge 1 ton, behind the Cummins. So now I have a lockup torque converter. I am operating it with a toggle switch on the dash. I thought that would be no problem but I ran into a situation where it was. Somebody pulled out on me when I was doing about 60 MPH and I had to do a panic stop. Jamming the brakes, steering the truck, just paying attention to what was going on, I didn't hit the switch to unlock the converter and it pulled the motor way down. It was like driving a manual transmission truck and not stepping on the clutch. I have heard that there is a way to wire a pressure switch in series with the toggle switch so that the torque converter will unlock at a certain mile per hour. Can anyone clue me in on what switch to get, and where to screw it into the transmission? Thanks, Joel It takes some work and I don't have the info on hand anymore but I used two adjustable Hobbs switches, one low pressure and one high pressure, two different part numbers because the adjustment range isn't that great. The low pressure is for unlock and the high pressure is for lock. If you don't have two switches the O/D will hunt at the set point, really annoying. I wired them with two relays so the low pressure switch closes but the ground goes through the high pressure relay so it doesn't engage until the high pressure switch is closed. The low pressure switch relay latches the high pressure switch relay closed until the low pressure switch opens and releases the relay. I ran the whole mess through the O/D driver in the PCM through another relay so as not to burn the PCM driver out and L/U only works in O/D. There is no way to separate it in the PCM. Mine works like factory, locks up at about 47 and unlocks at about 42. It will even kickdown. The port you need is at the back of the main case on the right side, opposite the rear cooler line. The switches in the stumped ones link didn't work for me as the governor pressures on the diesel are much higher. Gas models are typically 1 psi per MPH but mine had 60 psi at 30 or so MPH and over 90 at 60. You will need a pressure gauge to check what your governor pressures are at the speeds you want to lock and unlock, then order your switches based on that. If I come across the wiring schematic I'll post it, but lord knows where it is now.
"Follow me the wise man said, but he walked behind"
'92 D250 Club Cab CTD, 47RH conversion, pump tweaks, injectors, rear disc and hydroboost conversion. '74 W200 Crew Cab 360, NV4500, D44, D60 and NP205 divorced transfer case. Rear disc and hydroboost conversion. 2019 1500 Long Horn Crew Cab 4WD, 5.7 Hemi.
|
|
|
Re: How to control 47Rh lock up with a pressure switch?
[Re: Guitar Jones]
#3005331
01/14/22 07:05 PM
01/14/22 07:05 PM
|
Joined: Dec 2009
Posts: 20,647 in a cattle trailer down by th...
Guitar Jones
Paddle faster! I hear banjo music!
|
Paddle faster! I hear banjo music!
Joined: Dec 2009
Posts: 20,647
in a cattle trailer down by th...
|
Well it's not on my PC, I didn't think it was, so it's on paper somewhere. Alternatively you could splice your lockup toggle switch ground into the O/D ground wire to the PCM. That way when the trans comes out of O/D it will unlock the converter as well. I would run it through a relay though just to be sure you don't burn the driver out in the PCM. Blue wire is ignition hot, orange with tracer (blue or white, I forget which and I'm color blind so keep that in mind ) is the ground. Edit; the O/D kicks out at about 30 mph which is too low for the L/U clutch to be on, but it would at least unlock it before the trans downshifts into 1st.
Last edited by Guitar Jones; 01/15/22 01:30 AM.
"Follow me the wise man said, but he walked behind"
'92 D250 Club Cab CTD, 47RH conversion, pump tweaks, injectors, rear disc and hydroboost conversion. '74 W200 Crew Cab 360, NV4500, D44, D60 and NP205 divorced transfer case. Rear disc and hydroboost conversion. 2019 1500 Long Horn Crew Cab 4WD, 5.7 Hemi.
|
|
|
Re: How to control 47Rh lock up with a pressure switch?
[Re: Guitar Jones]
#3005352
01/14/22 08:46 PM
01/14/22 08:46 PM
|
Joined: May 2005
Posts: 4,740 Florida
BDW
master
|
master
Joined: May 2005
Posts: 4,740
Florida
|
Here's what I did for my 46RH 518 Control Completely automatic, wanted my daughter to be able to drive it. The control module automatically turns on/off the overdrive and lock-up for the transmission. The 518 (46RH) is hydraulically controlled and uses 2 servos to enable the OD and LU. The 3-pin connector on the transmission supplies the control voltages. The center pin always has 12V power connected. The 2 outer pins are switched grounds. The front pin is the OD ground, the rear pin is the LU ground. The module works according to the following sequence. 1) The 12V toggle switch supplies voltage to the relays and transmission center pin. 2) When the hydraulic pressure trips (50mph/adjustable) the pressure switch, ground is supplied to the vacuum switch. When speed is below 50mph, hydraulic switch opens, disabling OD. 3) When there is enough vacuum, the vacuum switch closes, providing the OD relay ground. Under heavy acceleration, vacuum drops, opens switch, OD is disabled. 4) When OD relay has ground and 12V, it waits 10sec, then supplies 12V to the LU relay and ground to the transmission OD pin, enabling OD. 5) Now the LU relay has 12V, it's already grounded. It waits the 10 sec programmable delay then provides ground to the transmission LU pin. So lock up doesn't occur until OD has been enabled and on for 10sec. 6) The programmable delays for both relays fix the situation when speed is fluctuating around 50mph. This would normally cause the OD to kick on/off, the 10 sec (programmable) delay stops this from happening.
Last edited by BDW; 01/14/22 10:36 PM.
|
|
|
Re: How to control 47Rh lock up with a pressure switch?
[Re: BDW]
#3005423
01/15/22 12:57 AM
01/15/22 12:57 AM
|
Joined: Dec 2009
Posts: 20,647 in a cattle trailer down by th...
Guitar Jones
Paddle faster! I hear banjo music!
|
Paddle faster! I hear banjo music!
Joined: Dec 2009
Posts: 20,647
in a cattle trailer down by th...
|
Diesels don't make vacuum, 50 psi of governor pressure is about 20 mph in a diesel and he already has O/D control in the pcm with a dash button to turn it off. I did find this adjustable fuel pressure switch at summit. Don't know how well it would hold up to ATF though. Summit pressure switchI remember having a hard time finding correct pressure switches and ended up actually talking to a Honeywell rep on the phone to get the correct part numbers. I don't remember where I purchased them from.
"Follow me the wise man said, but he walked behind"
'92 D250 Club Cab CTD, 47RH conversion, pump tweaks, injectors, rear disc and hydroboost conversion. '74 W200 Crew Cab 360, NV4500, D44, D60 and NP205 divorced transfer case. Rear disc and hydroboost conversion. 2019 1500 Long Horn Crew Cab 4WD, 5.7 Hemi.
|
|
|
Re: How to control 47Rh lock up with a pressure switch?
[Re: Guitar Jones]
#3005440
01/15/22 01:54 AM
01/15/22 01:54 AM
|
Joined: Jan 2003
Posts: 7,495 Minnesota
Hemi_Joel
OP
master
|
OP
master
Joined: Jan 2003
Posts: 7,495
Minnesota
|
Thanks for all the great information. I am not really needing full automatic control, I have been operating the overdrive with a toggle switch for years. In the occasional instances when I forget to switch off the overdrive, I have come to a complete stop, then got the truck rolling again with it overdrive. Then I notice it and hit the switch, but no real problem. Not so with the lock up. So I really need just a safety to disengage it if I forget, or in a panic stop. I think one of those adjustible pressure switches would do the trick.
[img]http://i.imgur.com/boeexFms.jpg[/img]31 Plymouth Coupe, 392 Hemi, T56 magnum RS23J71 RS27J77 RP23J71 RO23J71 WM21J8A I don't regret the things I've done. I only regret the things I didn't do. "Wise men talk because they have something to say; fools because they have to say something. ~ Plato"
|
|
|
Re: How to control 47Rh lock up with a pressure switch?
[Re: Hemi_Joel]
#3005477
01/15/22 10:30 AM
01/15/22 10:30 AM
|
Joined: Mar 2011
Posts: 3,087 Michigan
A727Tflite
master
|
master
Joined: Mar 2011
Posts: 3,087
Michigan
|
Thanks for all the great information. I am not really needing full automatic control, I have been operating the overdrive with a toggle switch for years. In the occasional instances when I forget to switch off the overdrive, I have come to a complete stop, then got the truck rolling again with it overdrive. Then I notice it and hit the switch, but no real problem. Not so with the lock up. So I really need just a safety to disengage it if I forget, or in a panic stop. I think one of those adjustible pressure switches would do the trick. Depending on how and where you drive just install a switch on the injection pump throttle lever. Fully closed it opens the L/U circuit. Or something off the brake pedal.
Last edited by Transman; 01/15/22 10:32 AM.
|
|
|
Re: How to control 47Rh lock up with a pressure switch?
[Re: Guitar Jones]
#3005507
01/15/22 11:35 AM
01/15/22 11:35 AM
|
Joined: May 2012
Posts: 1,841 South Bend
John Brown
top fuel
|
top fuel
Joined: May 2012
Posts: 1,841
South Bend
|
Diesels don't make vacuum, 50 psi of governor pressure is about 20 mph in a diesel and he already has O/D control in the pcm with a dash button to turn it off. I did find this adjustable fuel pressure switch at summit. Don't know how well it would hold up to ATF though. Summit pressure switchI remember having a hard time finding correct pressure switches and ended up actually talking to a Honeywell rep on the phone to get the correct part numbers. I don't remember where I purchased them from. Look for Hobbs Switches. W.W. Grainger used to have a bunch of different ones to choose from.
July 19th should be "Drive Like Rockford Day". R.I.P. Jimmie.
|
|
|
Re: How to control 47Rh lock up with a pressure switch?
[Re: John Brown]
#3005514
01/15/22 11:56 AM
01/15/22 11:56 AM
|
Joined: Aug 2011
Posts: 2,865 Pattison Texas
CSK
master
|
master
Joined: Aug 2011
Posts: 2,865
Pattison Texas
|
some older car & trucks have a dual brake light switch, one opens when the brakes are pushed & unlocks the converter, the other turns on the brake lights
1968 Charger COLD A/C Hilborn EFI 512ci 9.7 compression, Stealth heads, 4.10 gear A518 ODtrans 4100lb,10.93 full street car trim 2020 T/A 392 Stock 11.79 @ 114.5
|
|
|
Re: How to control 47Rh lock up with a pressure switch?
[Re: stumpy]
#3005585
01/15/22 02:36 PM
01/15/22 02:36 PM
|
Joined: Mar 2011
Posts: 3,087 Michigan
A727Tflite
master
|
master
Joined: Mar 2011
Posts: 3,087
Michigan
|
Most of those old dual brake switches actually interrupted the cruise control and turned on the brake lights. On all of the Chrysler vehicles in the 80’s up to the 90’s used the brake switch as an input, along with the N/S switch, VSS, TPS, battery (ambient temp) temp, coolant, trans temp, and some others. Depending on the algorithm, it controlled L/U, O/D.
|
|
|
Re: How to control 47Rh lock up with a pressure switch?
[Re: stumpy]
#3005588
01/15/22 02:40 PM
01/15/22 02:40 PM
|
Joined: Sep 2003
Posts: 19,485 north of coder
moparx
"Butt Crack Bob"
|
"Butt Crack Bob"
Joined: Sep 2003
Posts: 19,485
north of coder
|
Most of those old dual brake switches actually interrupted the cruise control and turned on the brake lights. that's what i was going to say. it unlatches the cruise unit, but i forget if it goes through the control on the turn signal stalk, or the unit itself under the hood. would be a super easy thing to wire up.
|
|
|
Re: How to control 47Rh lock up with a pressure switch?
[Re: moparx]
#3005638
01/15/22 04:35 PM
01/15/22 04:35 PM
|
Joined: Jan 2003
Posts: 7,495 Minnesota
Hemi_Joel
OP
master
|
OP
master
Joined: Jan 2003
Posts: 7,495
Minnesota
|
I would like the torque converter to stay locked up while I am using the exhaust brake, but still drop it out of overdrive if I choose to. If I use the brake light switch, and I want to use the brakes and the exhaust brake simultaneously, that would unlock the converter and reduce the effectiveness of the exhaust brake. So that pressure switch would probably be the way to go. Once I get the truck down to 40 miles an hour or so, the exhaust brake probably isn't needed. This truck is always very heavily loaded, with a big camper in the bed and/or my race trailer behind. So I actually prefer a mostly manual control so I can use my senses and my brain too make decisions rather than rely on an inflexible automatic device.
[img]http://i.imgur.com/boeexFms.jpg[/img]31 Plymouth Coupe, 392 Hemi, T56 magnum RS23J71 RS27J77 RP23J71 RO23J71 WM21J8A I don't regret the things I've done. I only regret the things I didn't do. "Wise men talk because they have something to say; fools because they have to say something. ~ Plato"
|
|
|
Re: How to control 47Rh lock up with a pressure switch?
[Re: Hemi_Joel]
#3005642
01/15/22 04:41 PM
01/15/22 04:41 PM
|
Joined: Aug 2011
Posts: 2,865 Pattison Texas
CSK
master
|
master
Joined: Aug 2011
Posts: 2,865
Pattison Texas
|
I would like the torque converter to stay locked up while I am using the exhaust brake, but still drop it out of overdrive if I choose to. If I use the brake light switch, and I want to use the brakes and the exhaust brake simultaneously, that would unlock the converter and reduce the effectiveness of the exhaust brake. So that pressure switch would probably be the way to go. Once I get the truck down to 40 miles an hour or so, the exhaust brake probably isn't needed. This truck is always very heavily loaded, with a big camper in the bed and/or my race trailer behind. So I actually prefer a mostly manual control so I can use my senses and my brain too make decisions rather than rely on an inflexible automatic device. Yep I understand that, but I am going to add a brake switch on my Charger, but I dont have a Jake Brake
1968 Charger COLD A/C Hilborn EFI 512ci 9.7 compression, Stealth heads, 4.10 gear A518 ODtrans 4100lb,10.93 full street car trim 2020 T/A 392 Stock 11.79 @ 114.5
|
|
|
Re: How to control 47Rh lock up with a pressure switch?
[Re: Hemi_Joel]
#3005706
01/15/22 07:06 PM
01/15/22 07:06 PM
|
Joined: Dec 2009
Posts: 20,647 in a cattle trailer down by th...
Guitar Jones
Paddle faster! I hear banjo music!
|
Paddle faster! I hear banjo music!
Joined: Dec 2009
Posts: 20,647
in a cattle trailer down by th...
|
I would like the torque converter to stay locked up while I am using the exhaust brake, but still drop it out of overdrive if I choose to. If I use the brake light switch, and I want to use the brakes and the exhaust brake simultaneously, that would unlock the converter and reduce the effectiveness of the exhaust brake. So that pressure switch would probably be the way to go. Once I get the truck down to 40 miles an hour or so, the exhaust brake probably isn't needed. This truck is always very heavily loaded, with a big camper in the bed and/or my race trailer behind. So I actually prefer a mostly manual control so I can use my senses and my brain too make decisions rather than rely on an inflexible automatic device. Great! I guess I don't have to feel bad for not finding the schematic then.
"Follow me the wise man said, but he walked behind"
'92 D250 Club Cab CTD, 47RH conversion, pump tweaks, injectors, rear disc and hydroboost conversion. '74 W200 Crew Cab 360, NV4500, D44, D60 and NP205 divorced transfer case. Rear disc and hydroboost conversion. 2019 1500 Long Horn Crew Cab 4WD, 5.7 Hemi.
|
|
|
Re: How to control 47Rh lock up with a pressure switch?
[Re: Hemi_Joel]
#3005708
01/15/22 07:19 PM
01/15/22 07:19 PM
|
Joined: Mar 2011
Posts: 3,087 Michigan
A727Tflite
master
|
master
Joined: Mar 2011
Posts: 3,087
Michigan
|
I would like the torque converter to stay locked up while I am using the exhaust brake, but still drop it out of overdrive if I choose to. If I use the brake light switch, and I want to use the brakes and the exhaust brake simultaneously, that would unlock the converter and reduce the effectiveness of the exhaust brake. So that pressure switch would probably be the way to go. Once I get the truck down to 40 miles an hour or so, the exhaust brake probably isn't needed. This truck is always very heavily loaded, with a big camper in the bed and/or my race trailer behind. So I actually prefer a mostly manual control so I can use my senses and my brain too make decisions rather than rely on an inflexible automatic device. If you are using a stock 47 and hauling all the weight using a Jake - you should consider some of the devices out there’s to crank throttle pressure/line pressure up. Closed throttle will drop line to 60 +/- and using the Jake with a lot of weight can take it’s toll on the clutch’s.
|
|
|
|
|