RPM Settings...

[k_williams1982]

What should my RPMs be at when I'm in "Drive" and holding the brake. My RPMs are at about 850-900 in "Park" and about 750 in "Drive". I noticed tonight that I'm getting a weird sound when sitting in gear and holding the brake. I was told it's the pump in my transmission getting ready to go out, so I started researching how hard it would be to rebuild a C6 myself. After talking to my dad, he says that my RPMs are too high (as soon as I let off the brake, the truck will start to move with no throttle on level ground) and that I need to back the idle down some. He says that I have the transmission under a load at all times and that he bets lowering the RPMs will make my noise go away. Is this possible, or is it time to yank the transmission out and either rebuild it or swap to ZF5. The transmission has no slip, shifts through all the gears just fine, and the fluid is still "pink" with a little color of "brown" in it. What is a good number to have the RPMs at in and out of gear? Thanks.

 

[LCAM-01XA]

Your rpms are indeed a bit too high - with the engine dead cold I get like 575 rpms in park and 550 rpms in drive, and when it's been running for a few hours the idle speed will climb up to about 675 rpms in park and 650 rpms in drive. 900 rpms in park is what I get when the high-idle and cold-advance solenoids are engaged upon cold startup. I'd turn the engine speed down if I were you, let the engine warm up good and shoot for 650 in park, that's the factory setting IIRC.

As for the strange noise, it could very well be transmission pump noise, but some transmission make it all the time both my E4OD and my AOD buzz like that, and they are bothvery healthy transmissions that are far from being on their way out. Both have shift kits in them too, so that may be a factory, but I hear the E4ODs in particular buzz from the factory, dunno how correct that is tho.

 

[david85]

Your rpms are indeed a bit too high - with the engine dead cold I get like 575 rpms in park and 550 rpms in drive, and when it's been running for a few hours the idle speed will climb up to about 675 rpms in park and 650 rpms in drive. 900 rpms in park is what I get when the high-idle and cold-advance solenoids are engaged upon cold startup. I'd turn the engine speed down if I were you, let the engine warm up good and shoot for 650 in park, that's the factory setting IIRC.

As for the strange noise, it could very well be transmission pump noise, but some transmission make it all the time both my E4OD and my AOD buzz like that, and they are bothvery healthy transmissions that are far from being on their way out. Both have shift kits in them too, so that may be a factory, but I hear the E4ODs in particular buzz from the factory, dunno how correct that is tho.

I agree with all of that. Some slushboxes just like to buzz. It doesn't automatically mean the transmission is dying.

 

[Andylad13]

Thats good news for me too, because I have the same noise when the truck is stopped, and have always wondered if something was amiss!