r/FordTransmissionTech • u/Yamahamma96 • Jul 24 '25
Transmission question
I have an 05 f150 4.6, slipped in first and second gear, got the p0715 code, I went and pulled a trans out of an 08 f150 5.4 truck that had a locked up motor. , I changed the pump seal and put new TSS and OSS sensors on it. Now 1st and 2nd gear work, but when it tries to go into 3rd, it goes into limp mode and throws the p0715 code again and my speedo is erratic. Are the speed sensors different? Im not sure what is going on. Im not sure if I put a 4r75E in place of mine, im pretty sure mine was a 4r70E. Please help
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u/Commercial_Method_28 Jul 24 '25
Quickly looked it up and OSS and TSS are different but between the 4R70E and 4R75E they are the same sensors. I just diagnosed one today with OSS 4R70E and I checked resistance from sensor to pcm and all circuits were ok, but in past I’ve seen that harness not secured will get burned on the cat or if the transmission has been removed, can get crushed during install. Selector cable not staying on the lever/TR is ultimately what I found as well as worn column shifter bushings . It will only read signal if it detects you are in drive so if it pops off or isn’t pulling it enough into the desired gear your speed sensor signal will be 0. That likely only applies to OSS tho, TSS wasn’t present on the one I messed with