weird shifting and psom

[terryknight]

some of the guys who may read already know about my problems, but I am going to repeat it here and see what other info I can find. I am really learn to learn more about how the e4od works.

I have a 97 PSD with an auto (duh) after hurricane Irene back in August the truck sometimes shifts funny (i was thinking something got wet, but it could just be a coincidence). It will shift very late and very hard from 1st to 2nd at 2500rpms or so and only 1st to 2nd. When it does this it sets a code for the VSS. after that it will shift very early at 1100-1200rpms and then out of no where it will drive fine. It will drive fine for weeks and then this problem pops back up again. It doesn't seem to matter it is is hot or cold (the truck) it is very inconsistent. I have replaced the VSS no change.

I have since learned that the VSS sends an analog signal to the psom and that that converts it top a digital signal to the computer and then onto the trans. The speedo uses the analog signal which would explain why the speedo always is correct.

I am looking for people's thought on whether I got a bad VSS and now have two bad ones, or if my PSOM is crapping out or if there is something else going on. This afternoon I am going back under the truck to look at the wiring and make sure nothing is messed up there.

[superduty4x4]

Usually when the PSOM starts to sign off the speedo will jump erratically. Have you inspected the tone ring in the rear end? If you suspect the PSOM you can swap the gauge assembly between your two trucks... you'll get some random lights that will turn on and what not but it will let you know if the PSOM is the culprit or not.

[1Dieselman]

Have you pulled the connector on the passenger side of the trans to make sure it is clean and dry. There is also a connector on top of the trans that should be checked. I would use a little di-electric grease when putting back together.

[Patrick Feeley]

Terry,

Have you thought of posting this over on TDS? Mark Kovalsky (former Ford Transmission Engineer) frequently answers posts on E4OD tranny issues in the 94-97 forum. I don't know if he posts over here or not. he might be able to provide some insight. Cheers!

[terryknight]

i have no idea what tds is

this is the only vehicle site i am on

[Patrick Feeley]

Sorry, it's TheDieselStop (.com). I'm on 4 just for PSDs. Cheers!