Dodge Trans.

[JStokes]

stock functions

When are the stock functions set for engagement? Does lockup only occur at freeway speeds stock or does it engage in other gears as well? If I leave lock up on and come to a stop will it kill the engine? Will I leave overdrive on for the most part except when towing?

 

[cerberusiam]

The TC lock and OD are controlled by the PCM based on TPS reading, speed, etc. If you hard wire a switch for the TC it will kill the motor at a stop sign unless youu wire it to relay that would be activated by the brake switch or ??? If you hard wire a swith for OD it will stay in OD from stop and never downshift.



If a person can source the right parts and know which ones are needed, there are probably only $35 worth of electronics in a setup to make this work. Getting the correct pieces is most of the battle.

 

[sdstriper]

I am doing a Cummins conversion in a Suburban and was planning on manual switches for OD, and lockup. How can I automate this. If I do automate them when do they come on and turn off?

My info is based on reading others experience here, almost all info from TDR members, some from the other 2-3 diesel forum sites online. I have been gathering 47RH info etc. (Word documenting for my project) from here and others for about a year now. So take it for what it is worth and do a little research yourself is my advice.



cerberusiam's concern is valid, although it is easy to control the TC lock-up and OD with a hyd. pressure switching from what I read. If you want manual control also I have read of three way toggle switching. Vacuum or hydraulic pressure switch control either function can and has been done with the Chrysler transmissions. The Chevy and Ford crowds have been doing this as well. The best info I have seen, as well as parts to get it done are available at the following site, I have no affiliation.



http://www.transmissioncenter.net/SwapInformation.htm



As far as Stand Alone Transmission Controllers, The transmission controllers are a few hundred to in the teens, fairly expensive for my taste considering what has been done with a few pressure switches and some creative wiring.



I'll add this, I have read and re-read these same requests for information, over and over and over again. Is this so unbelievable or a task that is extremely difficult to complete(pressure switching and wiring)? I don't think so. The info may not be labeled 47RH, and that could be part of the problem. Any opinions on that welcomed...

 

[cerberusiam]

I'll add this, I have read and re-read these same requests for information, over and over and over again. Is this so unbelievable or a task that is extremely difficult to complete(pressure switching and wiring)? I don't think so. The info may not be labeled 47RH, and that could be part of the problem. Any opinions on that welcomed...

I agree it is a relatively simple job to wire in pressure vacuum switches to control these functions, but, think about how you use OD and lockup for a bit and the ranges we deal with in oil pressure and vacuum.



Oil pressure generally runs 25 to 65 psi in the 5. 9 and it is very rpm related. Vacuum is even a lower range as it is driven off a pump not by engine load like a gasser. For the purpose of OD how do you vary engagement based on rpm and throttle position? If we are pulling hard we want to hold off until speed and rpm's are up to preserve the acceleration. Without electronics to overide the normal engage it will go when the preset is reached irregardless of conditions. Then, what happens when OD engages and rpm's drop and oil pressure drops? It is entirely possible to set a pressure switch to the point where it will constantly bounce due to the fluctuations.



TC lockup is even more critical as it is really hard on the input shaft to engage it under power. Unless you do billet shafts, which is a fair chunk of change, you run the risk of popping shafts and making a mess of the trans because of the limited control ranges. A dimmer or mystery switch is fine as long as ALL drivers recognize it and know how to use it, but, aroud mu house that ain't happening.



Let me stress this, I am NOT opposed to mystery or Hobbs switches and some down ingenuity. Both of my trucks have them and even I forget occasionally the lockup is on when stopping. :-laf They are just not very user friendly for a bunch of different people.



Yes, the stand alone controller is a bit expensive, but, it takes the unknowns out of the equation and gives an almost infinite adjustability to conditions and drivers. Everybody from sis to grandma can jump in and go without an in depth education on the workings, do's and don'ts. Plus, you won't have to fix any number of things that can break when an untrained person does the wrong thing.



Ok, dissertation over.

 

[Phil Stuart]

Do any of you have any recommendations as to where to purchase the 47RH? Thanks again

mbarn, If and when you decide to do a swap, let me know. I could use that there 727 for my old girl.



Phil S

 

[sdstriper]

A dimmer or mystery switch is fine as long as ALL drivers recognize it and know how to use it, but, aroud mu house that ain't happening.



Let me stress this, I am NOT opposed to mystery or Hobbs switches and some down ingenuity. Both of my trucks have them and even I forget occasionally the lockup is on when stopping. :-laf They are just not very user friendly for a bunch of different people.



Ok, dissertation over.

This is a point well taken, stopped trying to learn someone at our house how to drive a stick... :-laf