47RH transmission lockup question
#3279686
01/01/25 01:19 PM
01/01/25 01:19 PM
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Minnesota
Hemi_Joel
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Hi, in my 93 Dodge dually that I use for hauling my camper and towing my car trailer I had the original transmission replaced with a 47 RH so that I could get a lockup converter in it. It is set up with two toggle switches on the dash wired to the two solenoids in the valve body. One switch engages overdrive, the other switch locks up the torque converter.
Here's my question: the torque converter lockup only works in third gear and overdrive. If the transmission is in second or first, it automatically unlocks the converter.
Is there a way I can rig this up so that I can have the torque converter locked in second or even first? The problem is when trying to climb really steep mountain grades at 20,000 plus pounds, the transmission gets too hot because of torque converter slippage. I wouldn't normally want to engage the lockup before it goes into third gear but if I'm climbing a really steep grade and have to drop a gear, it would be nice to keep the converter locked up.
There's another odd thing that would be nice to cure, but not a necessity. If I'm cruising in third gear, and lock up the converter, then hit the switch to engage the overdrive, it won't engage unless I first turn off the lockup switch. Once overdrive is engaged, then I can lock up the converter again. Is there a way to make it so that if I'm in third gear with the converter locked up I can engage the overdrive without unlocking the converter?
Thanks and happy New Year. 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"
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Re: 47RH transmission lockup question
[Re: Hemi_Joel]
#3279835
01/01/25 09:33 PM
01/01/25 09:33 PM
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Posts: 75,369
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JohnRR
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I'm not sure why the trans is acting like that considering that OD and lockup are electronically controlled? I do know, though I was taught not to do it , that the RE version ... even though electronics were limited to the govenor pressure circuit and application of OD and lockup ... that you could use a switch to activate lockup and it would stay locked even if you stepped on the brakes which without the holding switch would unlockup it thru the PCM. From what I understand in 2001 the programming was changed so that the trans would shift from 3rd to OD with lockup applied , though it would pull engine power back some while making the shift, before that lockup won't happen till the trans goes into OD first unless the OD lockup button is depressed. That is how it is on my current 98 and my old 2000 Cummins Rams .
Hopefully one of our resident 727 specialists will chime in ...
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Re: 47RH transmission lockup question
[Re: Hemi_Joel]
#3279858
01/01/25 11:15 PM
01/01/25 11:15 PM
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Joined: Mar 2011
Posts: 3,255
Michigan
A727Tflite
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Hi, in my 93 Dodge dually that I use for hauling my camper and towing my car trailer I had the original transmission replaced with a 47 RH so that I could get a lockup converter in it. It is set up with two toggle switches on the dash wired to the two solenoids in the valve body. One switch engages overdrive, the other switch locks up the torque converter.
Here's my question: the torque converter lockup only works in third gear and overdrive. If the transmission is in second or first, it automatically unlocks the converter.
Is there a way I can rig this up so that I can have the torque converter locked in second or even first? The problem is when trying to climb really steep mountain grades at 20,000 plus pounds, the transmission gets too hot because of torque converter slippage. I wouldn't normally want to engage the lockup before it goes into third gear but if I'm climbing a really steep grade and have to drop a gear, it would be nice to keep the converter locked up.
There's another odd thing that would be nice to cure, but not a necessity. If I'm cruising in third gear, and lock up the converter, then hit the switch to engage the overdrive, it won't engage unless I first turn off the lockup switch. Once overdrive is engaged, then I can lock up the converter again. Is there a way to make it so that if I'm in third gear with the converter locked up I can engage the overdrive without unlocking the converter?
Thanks and happy New Year. Joel What year trans is it ? Was it a diesel or gas engine it came from?
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Re: 47RH transmission lockup question
[Re: A727Tflite]
#3279870
01/02/25 12:10 AM
01/02/25 12:10 AM
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Hemi_Joel
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When this transmission went in, I gave the guy who did it the transmission out of a '97 diesel 1 ton. But he said that he couldn't make that work the way he wanted to and he pieced it together from a variety of things. I never found out exactly what. Initially, I asked him the same questions that I am asking here but couldn't give me an answer. I don't talk to him anymore so I can't get any info.
[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"
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Re: 47RH transmission lockup question
[Re: Hemi_Joel]
#3279884
01/02/25 08:44 AM
01/02/25 08:44 AM
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Joined: Jan 2003
Posts: 75,369
A gulag near you.
JohnRR
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When this transmission went in, I gave the guy who did it the transmission out of a '97 diesel 1 ton. But he said that he couldn't make that work the way he wanted to and he pieced it together from a variety of things. I never found out exactly what. Initially, I asked him the same questions that I am asking here but couldn't give me an answer. I don't talk to him anymore so I can't get any info. 97 was an RE so he would have had to make changes in the OD unit ... probably easier to start with an RH OD unit ?? .... the rear rear OD apply piston which does double duty as the rear drum support, maybe the output shaft? and the valve body.
Mainstream Media is the new Pravda
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Re: 47RH transmission lockup question
[Re: A727Tflite]
#3279926
01/02/25 10:57 AM
01/02/25 10:57 AM
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Hemi_Joel
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This does not have any ECU control. It's all hydraulic except for the two switches. That's probably why he didn't use the transmission I gave him or whatever he did.
[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"
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Re: 47RH transmission lockup question
[Re: A727Tflite]
#3279927
01/02/25 10:58 AM
01/02/25 10:58 AM
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Minnesota
Hemi_Joel
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[quote=J_BODY]I would think there would be a way. I had a lockup switch on my 01 47RE just for that scenario. I’d only use it in manual 2nd though and wouldn’t upshift without disengaging. Funny thing is the 48re had that as a built in feature and hardly anyone knew about it. [/quote
Here is your answer... I have already tried holding it in second manually, then hitting the switch for the lockup. That didn't work.
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Re: 47RH transmission lockup question
[Re: Hemi_Joel]
#3279928
01/02/25 11:03 AM
01/02/25 11:03 AM
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Joined: Jan 2003
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Hemi_Joel
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Is there something in the hydraulic circuit that prevents it from locking up when it is in second gear?
Sick week starts in Valdosta Georgia later this month and I have to climb a long tall mountain between Nashville and Atlanta to get there. That hill is so steep and so long, I remember seeing broken down RVs and trailer rigs last time I climbed it. I'll have the camper in the bed of the truck and pulling the trailer.
[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"
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Re: 47RH transmission lockup question
[Re: Hemi_Joel]
#3280112
01/02/25 11:03 PM
01/02/25 11:03 PM
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Joined: Mar 2011
Posts: 3,255
Michigan
A727Tflite
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How can I figure out what transmission and valve body I have in it now. I'm not sure if it is an H or an e. RH has either a 2 or 3 pin oval white connector just behind the shift linkage. The RE has a larger round connector with multiple pins inside a black connector.
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Re: 47RH transmission lockup question
[Re: A727Tflite]
#3280377
01/04/25 08:40 AM
01/04/25 08:40 AM
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rust belt
Moparite
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in my 93 Dodge dually that I use for hauling my camper and towing my car trailer I had the original transmission replaced with a 47 RH What transmission was in it? I would assume it had lock up and overdrive. I'm not sure how the older pcm's operated the lock up. I believe if you hit the overdrive off button it would still allow lock up just not od. And do not tow in overdrive! It puts a extreme strain on the overdrive unit and will burn up the clutches. If you didn't do so already a external trans cooler is a must with towing.
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