engine brake while towing?
OK, so just getting a feel for towing my 5er with the 2013 Ram Cummins. When tow enabled (heavy tow used with appropriate tire pressure) and engine brake on, going downhill after taking foot off gas ...
Forum Discussion
ShinerBock wrote:wilber1 wrote:
The higher rpm will allow the pump to develop more pressure, that's a reason for delaying the shift.
Line pressure is controlled by the electronic pressure control valve/solenoid , not the pump.wilber1 wrote:
With a manual transmission, the diaphragm (or springs) in the clutch pressure plate doesn't get any stronger and apply any more pressure just because you are using more power or RPM. You can't regulate the pressure, only the rate at which it is applied.
The amount of pressure the pump can provide is limited by RPM regardless of what a control valve does. A valve can only regulate available pressure.
I guess you didn't understand my reference. I know how a manual transmission clutch works and that it doesn't get stronger once engaged. An automatic transmission also has a certain amount of pressure it can apply just like the springs in a clutch. However, I was using it as a reference when shifting (which is what we were talking about) and how your foot can regulate how smooth or firm a shift is just like an electronic pressure regulator valve/solenoid can in an automatic transmission.
What does that have to do with line pressure? With a manual clutch, the speed at which you engage it has nothing to do with how much pressure it can apply, that is determined by the diaphragm or springs in the in the pressure plate and can't be changed. Whether you drop the clutch or slip it, once it is engaged, the pressure it applies is the same.
An EB operating in a higher gear produces less braking power because RPM is lower and therefore requires less pressure for the clutches to remain locked than if it is in a lower gear at a higher RPM, just as accelerating at part power requires less pressure than at full power.
Logic would tell me that if EB use requires a higher line pressure and can be used without TH, pressures would be boosted whether you were in TH or not. Why would a manufacturer put his transmission at risk by not doing so? At the very least there would be cautions in the manual not to use the EB if towing and TH isn't engaged.
