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Hi, I've been having a chronic problem with my transmission, the 4R70W. While in "Drive," it will not want to shift out of 1st gear into 2nd without assistance from me by letting off the gas. It will shift into the other gears and will downshift with no problem. It will shift into 2nd if I shift manually with the lever selector at an appropriate RPM.
I receive a continuous memory code of 668, Transmission range sensor circuit above maximum voltage. Is the transmission range sensor referring to the MLPS? I've tested the resistance of the MLPS and it checks out within range of all positions.
Does anyone know how do go about checking the voltage and what do I need it to be? Perhaps this is a different problem altogether and I'm looking in the wrong place? Keeping my fingers crossed that it isn't something internal.
Further note- It started doing this about a year ago. The fluid was at the proper level and smelled sweet. I went ahead and did a complete oil change and the problem went away but came back a few weeks later.
Thanks to all!
Last edited by EllieMae94; Jul 7, 2019 at 12:35 PM.
Reason: Fixed
I want to give an update to the problem as I discovered and fixed the issue and hope this information can be useful to someone else in the future.
First, the symptoms that I described in my original post was not entirely accurate. It wasn't that there was a delay shifting into 2nd, but rather I had to rev the engine high enough for it to shift into 3rd gear, I had a complete loss of 2nd gear. While there was a CM code of 668 in the PCM, I checked the resistance of the Range Sensor at both the sensor and PCM ends, which was within specs.
I dropped the pan and removed the 1-2 shift accumulator piston and springs. The bottom spring (white) was broken into 3 pieces. The top (yellow) survived. Ford TSB 97-11-11 corrects a problem with the 1-2 accumulator piston that was used on the 4R70W. You can read about it here: https://www.tccoa.com/articles/mn12-...tsb/TV1111.pdf
After changing both springs, replacement piston, and a new cap, the transmission shifts great now. All I reused was the snap ring retainer.
That's correct. I came across the TSB after scouring the internet for hours looking for people with same tranny problem. I bought all the parts several months ago since they are so cheap. Removing the pan on this transmission is a little more difficult than most as the tranny has to be unbolted from the mount and lifted to access two bolts because the cross member is in the way. Also, I have a custom exhaust for my headers that interferes with complete pan removal so I had to drop it, first. Not a huge deal by any means, and certainly worth it to have all my gears back!
