...kind of looks homeless
Join Date: Oct 2011
Location: Fortuna, CA
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Harsh shifts mechanical or electrical
96 F350 4x4 CCLB E4OD 7.3
I have been having a harsh shift issue lately. It started suddenly about 2 weeks ago. My 1-2, 2-3, and 3-4 shifts are jarring but my TC lockup is silky smooth.
(One thing should be noted. Until today I have had a broken gear shift lever handle and no OD button or OD OFF light, so no flashing "OFF" could be observed.)
The only things that changed before the harsh shifts began: I had a gooseneck installed at a trailer shop. Welding was done and my batteries were disconnected and reconnected. I picked it up and was on the freeway within 1/2 mile. (Could being WOT on the freeway while the PCM was relearning its adaptive strategies affect line pressure baselines?) Did not experience harsh shifts for the entire drive home. (The harsh shifts had not begun yet.) The next day I drove the truck about 1/4 mile then executed a forced downshift at 30 mph from "D" to "2". Downshift was normal. Immediately after reselecting "D" and accelerating from the stop, my 1-2 shift almost knocked my teeth out. Transmission has been shifting harshly every day since then.
I have been pouring over the service manual and a bundle of E4OD files I have accumulated. It was starting to look like accumulator/valve body issues until I decided to keep it simple at first and disconnect the batteries for a few minutes and reconnect them to reset the PCM. I did it and went for a short drive. All of my shifts were perfectly smooth. They stayed smooth until today. I got my new gear shift lever in today from Ford and installed it. My first 1-2 shift after completing the installation was harsh, as were all the others, however TC lockup is still smooth.
Now my two questions:
1: Can I assume that my problem is electrical and not mechanical? After disconnecting my batteries, my problem went away for almost 4 days. If it were a mechanical problem (internal to the trans) there would be no way for the problem to go away, correct?
2: Can anyone tell me which sensors the PCM looks at when determining trans control? I know the VSS is looked at as well as the MLPS.
RockyardJo is going to spend some time giving me a scan with his copy of Auto Enginuity tomorrow. I'll post the results and maybe somebody can help translate. Thanks guys and gals.
1996 F350 --- D60, Warn Manual Hubs, RiffRaff 6637, 3" Diamond Eye Downpipe, TW Tunes, Gauges, Aeroforce Interceptor, JVC Head Unit w/ Bluetooth, Smoked Headlights, Blue LED dash, Factory RKE, Built Trans, TruCool Max, Black Interior In ProgressBlack Interior
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