I have an '03 ram 1500 4x4 with a 5.7 and a 545rfe transmission. When it hits 5th and at about 1500 to 1800 RPM the trans "hiccups". It's like it's trying to fall on its face. When I take it out of o/d it does fine because it's above 2k RPM. But even if o/d is off and the RPM hits the 1500 - 1800 mark it still hiccups. Any ideas? I'm stumped here. I don't even know where to start. Oh, there are no codes. None. Im not very well versed in automatic transmissions. So, even a starting point would be helpful.

 

What do you mean by "hiccups"?? Is it gear hunting??

 

No, it isn't gear hunting. It will be in gear, but when the RPMs reach about 1500-1800 it stutters. Like, maybe the engine momentarily lost power. Now, it may be that the problem is the engine as the RPMs do not go up when it does it. If you've ever experienced when a ring and pinion begin to go out, it is very similar to that feel. That feeling when the teeth start to skip. However, unlike losing a rear end, this only does it at the 1500 to 1800 RPM area. It won't do it when I put it in 2nd or 1st. It's almost like the more load you put on it the worse it happens.

 

Sure its not an engine misfire at low RPM????

 

after reviewing the matter, you have a very good point. I may have a coil or two going bad. But wouldn't the misfire set off a code?

 

Is the check engine light on? And if it was were you able to pull any codes. How is the transmission shifting?