bear with me long post coming up fare warning!
1996 Ford F250 XLT extended Cab 7.5 liter gas OHV and E4OD. Started having shifting issues, I noticed first that the O/D off light on the stick would blink after driving a few miles, was not sure why, but it would shift hard and go into Limp mode after a few miles. fine maybe shift Solenoid. $340 part, not replacing it unless I have to.

So I get underneath wiggle Juggle the MPRS connector, weirdly it shifts again goes through all the gears. for a while, I park the truck put it in park and shut it off. Start it back up, no shift, it starts in 2nd gear and stays in 2nd Gear. I go on the other side and check the Shift Solenoid Harness, Pull the shield, pull the plug, check for damage, no damage, plug it back in, no issue, no difference, I pulled the VSS, look at it, it's fine, I bench test it, replace it anyway, speedometer works Odometer works, Pull the PSOM and Speedometer assembly, take it inside send a signal into it and test the output on my oscilloscope, and it looks perfect.

Here's the thing. If it were the shift solenoid, it would probably not shift after wiggle jiggling wires, or at all. If it were the VSS, my speedometer and odometer would not work, PSOM is sending the signal to the TCM/ECM, and if the PCM/ECM was not working properly we would again have no shift at any time.

Thinking it is a connection somewhere, but I do not know where. What connector or what sensor would keep it in 2nd gear and make it start off in 2nd gear all the time. I am thinking I might fiddle with one thing at a time, then test drive between wiggle jiggling things to see if we have a shift. Has anyone else experienced anything like this before and what did you find out?

I also completely reset the ECM/PCM by pulling the battery and touching the terminals together for 10 minutes to clear out everything. still no shift. gotta be a connector or something, not making a connection.

Thanks for anything you can give me because I am seriously baffled here.

 

The flashing OD light means that the computer has sensed a failure and has stored a code. Unfortunately, you wiped out the code by disconnecting your battery. The code would have told you what had failed, or at least where to start. Pulling the codes is easy and fun with a paperclip and a pad of paper.

 

Drive it until the light starts flashing again. Then use this method to read the codes: www.troublecodes.net/ford.

Once you have the codes we can help direct what to check.

 

P0894 Actually I got the code before erasing it, it was "Transmission slip malfunction"

 

You are thinking of OBDI 1, this is the first year of OBDI 2, so the paperclip trick won't work, but I do have a code reader for OBDI2 that will read the codes, unfortunately this code reader will read engine codes but will not read Transmission codes. so I need to get a better code reader or drive it until I get the code again and take it to Eitehr Autozone or Oreilly Auto parts and have them read the codes for me. Not as fun, but at least it can be done.

 

Yeah we are going to go ahead and drive it for a while, also see if it will shift after clearing everything out. It is running very rough. Has not learned Long Term Fuel Terms yet they are at 0.00 Still. no Check light yet though. I think it is trying to bounce around and mess with it's mixture to learn where it is and adjust appropriately. we will just be real easy on it.

 

I've never seen an auto parts store that could read Ford transmission codes.

Get Forscan. You can download it free at www.forscan.org. Their page shows how to select an OBDII adapter to plug into the port. I bought mine from Amazon for about $30.

 

Okay I will check that out! Thank you!!

 

Your f250 has a OBD 2 port? California? EEC-V?

 

I was thinking the same thing. Im not sure what a "OBDI 2" is, but according the the OP, a paperclip wont work. From what I remember, F150s got OBD2 in 1995. F250-f350 OBS trucks never got OBD2, except for California trucks that got them around 1996, but I don't know exactly when the transition happened, or if it was true OBD2, or like the OBS diesel truck's "Quasi-OBD2".

 

Yeah Cali truck. Okay so I figured out that the transmission MSLP was bad, I replaced it, that respoved the no shift problem, but now if I drive it past 45MPH for a while the stick O/D Off will start blinking and it will go into Emergency mode. so I don't know how to get that code. Can anyone think of how to get that code? Then I can figure out what is causing it.

 

OBDII is a standard for diagnostics for vehicles, also known as OBDI 2 This truck is the first year of OBDII It uses J1850PWM Protocol to allow you to connect a Diagnostic Scan tool to the ECM to retreive DTCs and Codes, "Error Codes" Such as PO172 PO174 etc. The one the paperclip would work for is called OBDI or OBDI1 That is the old standard which used to be on older vehicles. This truck does not have that. it is a 1996 Ford F250 XLT G model in other words your vin has a G in it. You can look this up is you want to, it is actually pretty interesting. I thought it was weird too when I first bought the truck. The engine is a Direct Port Injection Ford 460 V8 7.5 Liter V8 and it is attached to an E4OD. So yeah you read that right, it was not a typo.

 

Mark posted the answer earlier:

Post# 7

 

Okay so would Transmission Slip Malfunction be possibly caused by a bad ABS/VSS rear wheel sensor? also I need to depin and repin my connectors for VSS and MSLP, they sent me new connectors for them, I have them I wonder if the fact that the connector is moving on the sensors might be causing disconnect issues, I replaced the VSS and MSLP and the issue seems to be resolved at low speeds, but not on the highway, after a few minutes of driving past around 45-50MPH O/D Off light starts Blinking and I get the code PO894 Transmission slip Malfunction. Okay so I know the only sensor on the back end is the VSS/ABS sensor which is brand new, but the plastic tab on the connector is broken so it is press on, needs to be depinned and then repinned with my new connector, and the Connector for the MSLP needs to be depinned and repinned with my new connector and for the same reason, the old plastic connectors are dry rotted and brittle, and the tabs broke on them. Could that cause this code? Could this cause the O/D Off light to blink on the stick? Should I start a new thread for this related issue even though the MSLP replacement resolved the shifting problem originally outlined in the title of this thread?

 

It is possible that a bad VSS could cause a P0894. More likely is something slipping in the trans. For a 1996 I would suspect a crack in the torque converter clutch apply piston, A quick way to see if that is the problem is to remove the dust cover from the bellhousing and look at the front of the torque converter. If it is slipping the front face of the converter will be blued. It should be unpainted, surface rust steel.

And it is MLPS (Manual Lever Position Sensor,) not MSLP.