545 RFE trans problems

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gmdodt

Junior Member
Joined
Oct 9, 2016
Posts
3
Reaction score
0
Ram Year
2004 Dodge Ram
Engine
4.7 V8
Hey all - I'm befuddled and looking for help

My 2004 1500 with the 4.7L was working mostly fine. At stops, sometimes it would not shift down to first gear. I replaced the solenoid block and input speed sensor and it still didnt fix it. Took it to the dodge dealer and they suggest warrantying the solenoid block, so I did, and put the new one in. Truck shifted great, but still did not always shift down to first at all stops. When I replaced the block I also replaced both filters and fluid the same as I did a month prior with the other solenoid block. In a last ditch effort to solve the problem, I replaced really the last sensor there was externally, the oil pressure transducer. The truck ran great, I parked it, took battery off, installed the sensor, took it out for a test drive, and all HELL BROKE LOSE. 6 engine codes popped up, truck stalled, then when it restarted it would not shift any higher than third gear. This was all in about .20 miles. Got it home, checked and cleared codes, took off battery and let it sit, then test drove it again. No codes, but wont shift into 3rd. Brought it home again and put the original sensor back in after disconnecting the battery thinking it would go back to normal. NOPE. Same thing, wont shift any higher than 2nd. Took to dodge dealer and a transmission shop and they said the brand new transmission fluid was black and that the trans needs a rebuild. How could swapping one tiny sensor cause this!?!? it was running great up until I replaced it and even tried putting the original one back in!! It just feels like more of an electrical problem.

To note, the original trans codes on the first test drive was a general TCM code and a code for each gear ratio (3,4,5). Subsequent, the CEL doesn't come on but the shop says P1790 is being thrown right when it tries to shift to 3.

If I do need a rebuild, I'm worried about what parts can be kept/not replaced if the transmission fluid is dark black..

Anyone have any thoughts? Truck only has 111k miles on it. Never towed. Very lightly driven
 

ST-8

Senior Member
Joined
Mar 26, 2013
Posts
2,470
Reaction score
989
Ram Year
2004
Engine
5.7
Usually p0734 n p0735 will spell doom for us. I put 2 transmissions in my truck before 104k miles, the last one was a junkyard trans that(knock on wood) seems to be holding up. For now..
 
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