E58 Automatics.

Transmissions and Rear Ends

  1. MBDale

    MBDale Well-Known Member

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    Is there anything special or specific about the 727’s that were behind E58 360’s??
     
  2. XfbodyX

    XfbodyX Well-Known Member

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    Looking at the dealer parts book #s and exchange #s it shows no diff in the trans, Ive never had a E58 727 act any different even in the converter area.

    I think more or less just a truck/van like 727.

    Looking at the power output of any factory E58 Im surprised they even bothered putting a 727 behind them.

    But ive been wrong before.
     
  3. CM360

    CM360 Well-Known Member

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    There were 2 e options for the 360 and it was just a HP difference like cams spec and I think head choice. You could get a 904 with either option. e was intended for police car use but it became blurred during those production years.
     
  4. BudW

    BudW Moderator Staff Member

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    Police (and older higher revving HP engines) have different governor springs/weights to allow for higher shift points.

    Also, All HD transmissions contain a higher number of clutch disks in the clutch packs.
    BudW
     
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  5. MBDale

    MBDale Well-Known Member

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    So the valve body is different?
     
  6. BudW

    BudW Moderator Staff Member

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    The ‘75ish and older transmissions, the governor springs and weights were different on police and on HP (high revving) engines. When looking into this for another member, the governors are the same for all 1986 A904/A999’s. The differences are inside of the valve body - for the higher shift points.

    I’ve yet to look into the differences on late 70’s/early 80’s transmissions so somewhere there had to be a break between differences in valve body vs. governor.

    Note: A727 and A904 (and variations) valve body's look the same at a glance - but will not interchange. It is no fun trying to determine what a "loose" valve body came out of - if you work in an area where transmission repairs take place.
    In many cases, the same model transmission valve body will not interchange with the next year up (or down) without complications.

    I have the A999 out of an ’84 M police car – which I saved because of its higher shift points.
    BudW
     
  7. XfbodyX

    XfbodyX Well-Known Member

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  8. XfbodyX

    XfbodyX Well-Known Member

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    MBDale It would be alot easier to give you proper info if you could get the PN number off the trans you are talking about.
     
    Last edited: Dec 12, 2019
  9. Locomotion

    Locomotion Well-Known Member

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    Gotta watch the difference between lock-up and non lock-up transmissions/converters. Converters and valve bodies don't interchange. Also, at some point, a 2.74 low gear was introduced into the 904 line. But I don't know the exact dates or combos that determine which had or didn't have any of those differences.