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transmission wont shift gears when in drive

transmission wont shift gears when in drive

  #1  
Old 06-28-2018, 02:20 PM
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transmission wont shift gears when in drive

1999 Ford F150 with 4.6 L Crown Victoria engine with Ford 4R70AOD transmission for 4.6.
Could the PCM not be reading the rpm to change the gears? Do I need a PCM or do I have to get the existing one programmed?
 
  #2  
Old 06-28-2018, 06:39 PM
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Please be more specific with the problem description before worrying about specific components.
 
  #3  
Old 06-28-2018, 06:46 PM
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When placed in D the vehicle moves and as acceleration increases there is no shift change. This issue also took place with a previous transmission. No fault codes.
 
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Old 06-29-2018, 02:01 AM
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Will it manually shift from 1 to 2 to D? In D, what gear does it seem to be stuck in? What happens if you hit the OD button?
 
  #5  
Old 06-29-2018, 10:46 AM
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No, only shifts from D to 1 manually not shifting from 1 to 2 in D. Moving shifter from Park or Neutral to D it engages and the rpm goes up upon acceleration but the gears wont change. It changes manually when shifter is moved from D to 1. No response or changes when OD button is pressed
 
  #6  
Old 06-29-2018, 03:51 PM
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Still not sure of what you are trying to say, but it sounds to me like it may be stuck in 2nd when it's in D?

Start in 1, then shift to 2 - does it shift? Get it up to about 40 mph in 2, then shift to D - what happens?
 
  #7  
Old 07-06-2018, 10:43 AM
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I also suspect that it's only got 2nd gear going forward. Likely due to either an electrical issue or incompatibility with the computer since this appears to be a swap situation.

D
 
  #8  
Old 07-06-2018, 10:45 AM
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So lets start here. You told us the year of the truck, I think. What PCM is in the vehicle. Year info is critical here. And, what year is the transmission?

D
 
  #9  
Old 07-08-2018, 07:23 PM
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I been out of town and just got back an hour ago.
The transmission engages freely when the lever is moved from park through to 2nd. It does not go into 1st.
The transmission that is currently in the vehicle was recently installed. It replaced the original one from time of assembly and there is no change. I believe that its either an adjustment issue or a computer issue.
 
  #10  
Old 07-08-2018, 07:24 PM
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The PCM that is in the vehicle now is the one that came originally from the factory at time of assembly
 
  #11  
Old 07-08-2018, 07:35 PM
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Yes I believe so as originally the unit came with 5.4L engine and transmission. The engine was replaced with a 2001 4.6L Crown Vic engine and I only found out after purchasing it. That's what you get for $600 bucks. I took it as a project so my son can have a vehicle to use. Now I was told by a transmission guy that the PCM is unable to read the transmission hence no change of gears due to incompatibility. He suggested I replace the engine or the transmission. I replaced the transmission with a re manufactured one for the vin number and compatible with the 4.6L. The problem remained the same. The transmission wont shift into another gear when placed in drive and would only change when the lever is moved manually. So using a Launch OBD2 scanner no fault codes were found. No check engine light is on. The over drive light is NOT illuminated and the button is pressed all the way in and cannot come out.This leads me to think that the PCM is at fault.
 
  #12  
Old 07-08-2018, 10:24 PM
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The only way the PCM would be incompatible is if the truck came with a 4R100 transmission, and you replaced it with a 4R70W (or vice versa). Almost all 2001's came with a 4R70W, but a few 5.4's did have a 4R100, some of the 7700 payload package trucks with 7 lug wheels. What is the TRANS code on the door jamb sticker? 4R70W is code "U", 4R100 is code "E". Either transmission is compatible with either a 4.6 or 5.4, but you have to have the correct PCM. A 5.4 PCM will work with a 4.6 and vice versa. A 4R100 PCM will NOT work with a 4R70W, and vice versa.

If the manual lever will not move down to 1, you have a linkage adjustment issue or an internal transmission problem.

If the overdrive button is stuck, that's also an issue that needs to be addressed.
 
  #13  
Old 07-09-2018, 11:11 AM
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Transmission code is U
 
  #14  
Old 07-09-2018, 11:15 AM
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  #15  
Old 07-09-2018, 04:43 PM
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If the "new" transmission is a 4R70W, the PCM is compatible. You can tell what you have by the pan shape.


 

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