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Member
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132 Posts
Discussion Starter #1
hi,
dropping in a 47RH in my 1992 next weekend and need info on the overdrive / torque converter controls. will my present PCM control the overdrive and i simply need a hobbs switch for the lockup or will i need two hobs switches...
i presently have a potentiometer on the dash for my overdrive instead of the TPS.
also what pressure hobbs... any good write ups anywhere.
thanks. option two is mounting a 2cd gen pcm... i have one, what is involved in doing that....
thanks for any info.
Eric
 

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An A/C low pressure cutout in the govenor test port should serve for lockup at about 44 psi. The current controls for OD will work. If the A/C cutout is not the range that you want the govenor pressure is close to 1 psi per mph.
 

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Discussion Starter #3
thanks for the input, sounds simple enough, am i right in understanding that this will make the torque converter lockup at a set speed but not necessarely in overdrive only. so, if im still in 3rd at 44mph the converter will lock up and stay locked into overdrive as well... or will i get pressure at the switch only when in overdrive.

Eric
 

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There are 3 wires on the transmission, one 12v and 2 that are grounded to lockup the converter and apply the OD. You currently have an OD control that will work the same, you just need to add a control for the lockup and change the wireing connecter to fit the transmission.

The converter will lock at road speed reguardless of the transmission gear if I read the hydraulic circuit correctly, with the reostate mod the OD shift point can be moved around some. The OD can also be run from the govenor test port but I would add a switch to turn off the OD.
 

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Discussion Starter #5
thanks for the info, i just bought a totalled 2cd gen so i have the necessary transmission / wiring connectors.
ordered a variable hobbs switch off ebay so i should be good to go, its nice to know the converter will lock up in 3rd as well depending on set point, of course the manual override can take care of that, i look forward to trying it out.

Eric
 

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What are sparkplugs
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Will the dodge NP205 bolt to the back of the 47rh? Reason I'm asking is I'm going to be installing a cummins and a 47rh in my chevy. I see eric that you have installed a 47rh, is your dodge 4x4?
 

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The 205 Tcase will bolt onto the 47RH. Just make sure to remove the rear seal that the 47RH has in it.
 
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What are sparkplugs
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That's what I needed to hear! Thank you that helps my project out alot!
 
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