I just bought a 2007 Ram 1500 that has 45000 miles on it. 2wd, 4.7l, quad cab, flex fuel. Truck ran fine for 700 miles, then I started hearing a ratcheting noise when I would crank the truck up and go from park to reverse. I crawled under it and it sounds like some kind of solenoid trying to engage, but it can't for some reason. Also, it only happens when the transmission is warm and idling fast. If you let the idle go down to about 700rpm, it doesn't make any noise. Only when it idles above 1000rpm does it happen. I have read several posts similar to this, but nobody seems to have an answer. I took it to a Dodge dealer and couldn't get anyone who knew what I was talking about. Took it to a transmission shop and the guy said that all later model Chryslers did this. Another question - should the truck be idling that high after it is warm. It doesn't seem to matter how warm the engine is. When it fires off, it starts at about 1200rpm, then after 15 seconds it gradually starts to creep down to about 650rpm. I don't understand why it has to idle that high if it is hot. I did reset the PCM using the 31st fuse method and I unhooked the battery for about a half hour just for kicks. About the only other issue with the truck is that it downshifts from 4th to 3rd very firmly. So firmly that it is almost a clunk. After I reset the PCM, this problem appeared to be resolved, but now it is back. Also, it would hold onto a shift longer when accelerating after I reset it. These two symptoms seem to go hand in hand. Transmission fluid is full and very clean. Truck runs very smooth and tight. Any help on this would be greatly appreciated.
2007 Dodge Ram 1500 Transmission Ratcheting on 2007 Dodge Ram 1500
by nixont in Plainview, TX on February 21, 2011
ANSWER by Johnny Mopar , March 04, 2011
The ratcheting noise is common coming from the shift solenoids. You next question about high idle is usually caused by a dirty throttle body or a small vacuum leak at one of the many vacuum hoses. Throttle Body Service The throttle plate and bore may become coated with contaminates from the intake system. This will restrict the air flow past the throttle plate when the throttle is closed. The Idle Air Control Motor (IAC) may not be able to compensate fast enough to keep the engine at the target idle speed and stalling occurs. If the throttle body plate and bore are coated with contaminates, perform the Cleaning procedure. You will need 04897156AA Mopar Throttle Body Cleaner, Scotch Brite Pad, (Green) or soft Bristle Brush. Remove the throttle body from the engine. Spray the entire throttle body bore and both sides of the throttle plate with Mopar Throttle Body Cleaner, p/n 04897156AA. This will remove the bulk of the contaminant. CAUTION: This cleaner should only be used in a well ventilated area. Do not allow contact with skin or eyes. Rubber or butyl gloves and safety glasses are recommended. Wash thoroughly after use. Do not ingest. NOTE: Use only Mopar Throttle Body Cleaner, the use of other cleaning agents may damage components of the throttle body. While holding the throttle open, use a small, (1” x 1”) piece of green Scotch Brite scuff pad, (or soft bristle brush), clean the throttle body bore and throttle plate, (including edges). NOTE: It is important that this cleaning procedure be performed thoroughly and completely. The edge of the throttle plate, and the portion of the throttle body bore where the throttle plate comes to rest are the most critical areas where the cleaning should be concentrated. These areas must be free of all deposits when the cleaning is completed. Thoroughly clean the throttle body with Mopar Throttle Body Cleaner, p/n 04897156AA, and blow dry with compressed air. Inspect for any foreign material which may have been left from the cleaning process. CAUTION: Do not blow shop air pressure directly into the throttle shaft or throttle body housing holes. FYI, when you disconnected your battery, the PCM lost it's learned memory and is re-learned when driving your vehicle around over a given period of time. This will also affect your transmission shifting.