Engine/Transmission (1998.5 - 2002) RH-RE what is the difference?

[CNorthrup]

Just wondering if the difference is only the valve body? Could you use the later version if you changed the valve body out. I am thinking about a transmission change from the 5600 to an auto without changing the ecm and just have a switch for the lockup and the overdrive?

 

[Road Dog]

RH for Hydraulic and RE for Electronic. The RE needs a PCM which controls some solenoids inside the transmission. It looks like every truck has a PCM since it does other stuff (A/C clutch, gauges, cruise control, odometer, ... ) but it might need to be programmed to recognize the transmission. With a Diesel the ECM manages the fuel.

 

[cerberusiam]

You can use either the RE or RH. You cannot swap VB's between them becuase of the differences. The main difference between the 2 is how governor pressure is generated and used. The RE requires a module to set pressure based on feedback from a pressure sensor.



If you use the RE you will need to get a PCM\harness to control the gov pressure or go to a stand alone unit.



An RH will require an output shaft change to match the t-case input and possibly modifying t-case mounts and possbly drive shaft(s). The RH OD unit is longer than the RE and not sure if you can mix the adpaters.

 

[CNorthrup]

I just read an article in one of the diesel magazines where they put a 47rh out of a 95-96 cummins in a first gen and used a switch for the OD and the lock up. My truck is 2WD so I don't have to worry about the transfer case. I have access to a transmission out of a 2001 but was trying to figure out if I can avoid finding the right ecm/pcm. In my opinion the less electronics the better. That is why I wondered if the valve bodies were interchangable.

 

[cerberusiam]

Check around, you may be better off putting the RE in and finding the correct harness\PCM. Finding a good RH is dicey, they have been out of production so long that you would have yo pay the price for a rebuilt unit or get lucky and find one.



The RH would be fine in a 2x4 but you will need the drive shaft for an auto I believe. The switches will work fine if you don't mind doing it manually.

 

[CNorthrup]

Thanks for the reply, just kicking around ideas. I have been rebuilding 727 since I was 17 so finding a used one is not a problem. Why pay someone to do what you can do yourself! A valve body swap would be easy if that is the only difference. Fabricating the right linkage is no problem or just set the pressure at a constant and use a manual valve body, just like we do in muscle cars.