There's some rust on my transmission dip stick, what type of sign could this be? And I had the truck running for over 30 minutes idling, should the transmission fluid level be over the cold level and up...
If you are in Park, and running ... there is little activity in the transmission. I would say you are probably "cold" at this point. On the other hand, if you drive around the block, there is a lot of activity in the transmission and you are probably "hot". I wouldn't add any fluid based on your observation today. I would check it again tomorrow and see what the level is.
Here is a tip: Never add all you think you should at one time. It is a bear to get the fluid out and over filling is worse than being a little low. If you over fill, the tranny will whip the oil up into a frothy mixture, the oil will expand and do little lubricating. Frequently, when this happens, the oil runs out the fill tube onto the hot manifold and there is a fire as a result.
As far as the rust goes ... surface rust on the dip stick isn't much of a concern. It would tell me there is no oil coating on the bare metal. When moisture gets on metal - rust. So, how does the moisture get in to do the rusting? When your transmission is hot, the air inside gets hot and it expands. The extra air escapes out the fill tube and in come cases a breather. When you park, the machinery cools down, the air 'shrinks'. When this happens, 'fresh air' is drawn into the fill tube. Sometimes, the cooler air is heavily laden with moisture ... the moisture condenses onto the metal parts (and onto the oil) causing surface rusting. The water that gathers on the surface of the oil will eventually sink. Next time you go out, the machinery gets hot ... the water evaporates and mostly escapes out the fill tube with the hot air. When you turn the machinery off, ... this process starts all over again.
I hope I have addressed your concerns today, and I hope this makes sense to you. Thanks for your interest in FixYa.com and thanks for your visit.
Jan 11, 2011 |
2003 GMC Envoy