1987 - 1996 F150 & Larger F-Series Trucks1987 - 1996 Ford F-150, F-250, F-350 and larger pickups - including the 1997 heavy-duty F250/F350+ trucks
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F250 hard shift even after replacing transmission. (1994 F250 7.5L E40D) *Please Help
Ok my apologies if this gets long winded but I have researched and replaced a bunch of parts and keep having the same problem. I even took my truck to a transmission shop and after $150 they told me it was a speed sensor (ABS) and that ended up being incorrect.
PROBLEM: OK so for the last 3 years my truck has been randomly hard shifting it would be fine for a few days or even a month. but more recently it does it all the time. I have read a lot of posts where people had the same problem but was able to be fixed quickly with a sensor. I have not been so lucky.
So before last week I replaced the speed (ABS) sensor on the rear differential. I then replaced the MLPS sensor (neutral safety switch) still had the same hard shifting. I was then told that since the trany is electronically controlled that the solenoid pack could be going out, so I replaced that. At the same time I replaced the solenoid pack I also replaced the torque converter. Still had the problem I then decided to replace the throttle position sensor, but yet again the truck acted the same.
So I was on my way to work Thursday and the truck felt like it was dropping out of gear and I thought that with all the changes I have made it has to be the trany. So last Saturday I replaced my transmission did all the normal stuff during the install of the new trany. New fluid new filter I even drained the fluid out of the torque converter. I bolted everything back up and took the truck for a drive. Same thing even with a different transmission. NOTE: The old trany had a mound of shaving that the magnet caught so driving while the hard shift was happening was not a great idea. I hope I can resolve this issue use so I can use my truck
So I went to the auto part store and asked if there is any other sensors that the truck uses to tell the trany when to shift. They found a pressure monitor unit (I know thatís not the name but donít know what itís called) and they said that it determines how fast the engine is running. So once again I paid more $$ just to find out that was not the problem.
Is your Speedometer working OK and steady?
If so, it sounds like it could be the Speed Control Module.
Try unplugging it and drive and see if that helps.
If not, try unplugging the RABS module and see if the Speedometer works OK and the problem goes away.
If the Speedometer still has a problem then it would be a PSOM or bearings in the rear end.
You would have to check the AC voltage from the VSS (ABS) sensor in the rear end to find out the item causing the problem.
You should get around 3.5 VAC from the rear end with both the PSOM and the RABS module unplugged.
Not sure if either of these will set a code but it is always good to check like Lazy K and LCAM-01XA said above.
If you do not know how to see if you have any codes in CM go to this link: Ford Fuel Injection How To Run a Self-Test
as Lazy K said above.
I will check the codes again tonight in the past I have not had any luck pulling off any useful codes.. There the check engine light NOT on and the OD light does not blink. That is two questions I seem to get a lot.
On a side note:The last part that I got was a Master Pro Ignition - Sensor-Map (2ms22)
Well this is interesting I got a new code that I donít remember getting before. Below are the codes that I received.
111: System pass
10: Cylinder #1 Failed Cylinder Balance Test.
668: Transmission Manual Lever Position Sensor circuit open
111: System pass
I have replaced the MLPS (manual lever position sensor)/neutral safety switch already. Also replaced the plug that goes to the MLPS.
Subford: Donít know about the cylinder balance test that is just the code that showed up. Thanks for the great photoís this helps tremendously, I will try your suggestions tonight when I get home and will post my findings.
OK I unplugged the speed control module and took the truck for a test drive and it had no effect truck still shifted hard.
I then plugged the speed control back in and unplugged the RABS module and took the truck for a spin also had no effect still had the hard shift.
I have yet to test the voltage going to the vss sensor I will check that after dinner.
After I plugged the RABS back in I checked the codes and I got two new codes.
654: MLP sensor not in park position
452: Computer detected an error in the VSS or PSOM signal during the last 80 warm-up cycles
668:Transmission Manual Lever Position Sensor circuit open
Interesting enough there is a plug in back of the glove box that says PSOM that does not go to anything should that be plugged into something?
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