I have a 2004 Dodge Intrepid and not to long ago my check engine light came on and went into limp mode. I changed the TCM and the light came on but it drove without any slipping or shift problems until it decided to go into limp mode again. The codes again came up p0700 and I had my mechanic look it over again. He checked the wiring and ground and that was ok and reset the codes. After 2 weeks it came on again and went into limp mode. We do not think it is the transmission because it never slipped or shifted hard or not at all when the light was not on but as soon as the light came on it went into limp mode. A few years ago I had the transmission fluid changed when the car had 60,000 miles on it. I read that if the transmission filter is not replaced that could cause these problems as well. Is that a possibility? The car has 88,000 miles on it now. Thank you
Code 700 is in the Engine Computer. It just means there is a code in the Transmission Computer. Not all aftermarket scanners will read anything other than engine codes so you might have to find a different mechanic.
You will never feel the slippage that the computer can detect. It's not like the engine "runaway" that we got many years ago from the hydraulically-controlled transmissions.
Here's some generalizations. If you start the engine, then as soon as you begin to move, it goes immediately to limp mode, it is more likely to be sensor-related. The same is true if you're cruising at a steady speed when no shifts are taking place.
If it bounces down to limp mode right after or during an up-shift, it is more likely to be slippage in one of the clutch packs. Here's a hint. If it always occurs when up-shifting only from second the third gear, accelerate harder than normal, then let off the gas a bunch to let it shift to third with no load. You can accelerate again once it's solidly in gear. If the trick works, you can be pretty sure it's clutch slippage.
Besides reading codes in the Electronic Automatic Transmission Controller, (EATX), the Chrysler DRB3 scanner will also display the "clutch volume index", (CVI). That is a set of four numbers corresponding to the number of ccs of fluid it takes to apply each clutch pack. I don't know what normal is, but an experienced transmission mechanic will. As the clutch plates wear they become thinner so it takes more fluid to squeeze them together. The computer watches those numbers and uses them to update the shift schedules. To avoid the typical engine speed flare-ups that were common indicators of bad things to come, the computer eliminates that by turning on the solenoid to apply one gear a little sooner before it releases the previous gear. That way by the time one clutch pack is released the next one will be fully locked up. The result is nice crisp shift until the day when no amount of updating can overcome the wear. What you don't get is the year or two of warning that you'll be needing a rebuild soon.
I wouldn't panic about the mileage since the last fluid change.