ECMN | Offroadnt - 10/26/2011 21:21
The transmission pump always runs with the engine or your transmission wouldn't work, the only difference between "P" and "N" is the park latch is engaged in "P", have you tried letting the truck idle in "P" for ten seconds before you move? Should be the same thing. All torque converters drain down when not running, that's why you check transmission oil level with the engine running.
I think your getting some slippage in your reverse clutch when you put it in reverse, does it do it in drive also?
I have never worked on one of these transmissions but I agree that unless the Mopar folks have some new fangled design the trans pump is most likely driven by the torque converter hub. So I agree that when the engine is running the pump is pumping fluid somewhere. However I have overhauled several Torqueflite 904 & 727s in my day. Both of these transmission have different fluid path between park and neutral. One difference is that I'm almost certain that the oil is not pumped through the cooler circuit in Park. Which I think (but am not certain) the cooler is either fed or is feeding flow into or from the converter. So if you looked at the dipstick on one of these trannys from the '60s - 80's vintage is would tell you to check the fluid level hot idling in neutral. If you started it up and checked it in Park the level read higher then if checked it in neutral. So if the good old engineers followed suite on these trannys I would guess that what Tim in WI is saying may have some merit. |