Different color transmission modulators

Discussion in 'General Ranchero Help' started by Gregory Cummings, May 16, 2019.

  1. Gregory Cummings

    Gregory Cummings In Second Gear

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    Location:
    Oceanside, CA
    ok Chero fans, So I went to autozone to just check on what size hose I needed for the manifold vacuum to transmission modulator I needed. first of all I did'nt know which transmission I had C4 or C6 AOD for my '79 351/400M ranchero. He brought up several modulators with different color codes. Well now, what the heck. red, green yellow or orange strip ? ? ?. What do the color coded modulators mean. Different shift perameters I thought. so I'm guessing what size hose and what striped color coded modulator, any thoughts would be cool.
     
  2. rancheromac

    rancheromac In Third Gear

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    143
    probably have an FMX, not sure of color stripe much except I heard black stripe is for strip use ? anybody else know?
     
  3. handy_andy_cv64

    handy_andy_cv64 In Maximum Overdrive SILVER MEMBER

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    Everett, WA
    First, look at the door tag. 'X' means FMX, and as long as its the original trans, it's likely the modulator is also original. Just shinny underneath with a rag, carefully clean it enough to see the stripe, which goes around the body. Just so you know, FMX's have a bolt-on bellhousing.
     
  4. Carl Steinbarger

    Carl Steinbarger In Second Gear

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    Location:
    Dayton, Ohio
    I do know for a c4 the modulator should have a green stripe...
     
  5. Doc76251

    Doc76251 In Fourth Gear

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    Location:
    Virginia Beach, VA
    Did a green stripe on my 77 FMX, I haven't come off the original setting but it shifts much better and I no longer have trans fluid in my vacuum lines. I may decide to firm it up while I am underneath it looking for an errant fluid leak. As I understand it you turn the little adjusting screw inside where the vacuum line attaches CW to firm, CCW to loosen. I know it should be done with a pressure regulator etc. but I'll settle for a seat of the pants feel. Also as I understand it NO MORE than 2.5 turns from stock in either direction. Make sure you find and keep the "rod" that may or may not come out when you pull the original part, you have to put it back in, it is the actuator rod. There are those that adjust the overall length of the rod but I will let you research that on your own because I don't recall the details.

    Cheers,

    Doc

    Edit to add: you NEED a VERY THIN wrench to get that hummer in and locked down, mine came out by hand but I ended up using a table leg adjusting wrench that I had (stamped non hardened sheet metal) to get it tight.
     
    Carl Steinbarger likes this.
  6. andrewok1

    andrewok1 In Maximum Overdrive GOLD MEMBER SILVER MEMBER

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    DOC,
    had no idea you are a transmission Medic also:D
     
  7. Doc76251

    Doc76251 In Fourth Gear

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    347
    Location:
    Virginia Beach, VA
    Oh shit no dude! Anything that happens aft of the flex plate an forward of the drive shaft is PFM. I took me 45 hrs of Google to figure out a vacuum modulator and even that was a crap shoot. I'm just passing on what I learned. I'ma buy a T-56 turn key and bolt it in but I still need to figure out the clutch pedal as a 77 never had one. Now if you need a total hip or knee I can walk you through that step by step.

    Cheers,

    Doc
     
  8. handy_andy_cv64

    handy_andy_cv64 In Maximum Overdrive SILVER MEMBER

    Messages:
    8,857
    Location:
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    As a technician myself, PFM is all too real. And no, 'PFM' does not stand for "Pacific Fast Mail."
     
  9. Gregory Cummings

    Gregory Cummings In Second Gear

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    Location:
    Oceanside, CA
    forgive my ignorance but what is FMX.
     
  10. Gregory Cummings

    Gregory Cummings In Second Gear

    Messages:
    65
    Location:
    Oceanside, CA
    forgive my ignorance but what is FMX.
     
  11. ForistellFord

    ForistellFord In Maximum Overdrive GOLD MEMBER

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    Beautiful Foristell Missouri

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