400i automatic shift points | FerrariChat

400i automatic shift points

Discussion in '365 GT4 2+2/400/412' started by zman, Jul 14, 2013.

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  1. zman

    zman Formula Junior

    Jan 14, 2006
    356
    Toronto, Ontario
    What are the shift points on the automatic? Reason I am asking is I just seen that the wires going to the throttle shaft which goes to the tranny is disconnected and wondering if this is why its shifting too early.
    Also when I step on it, it doesn't kick into gear, It will kick in if I slow down and then step on it but if at highway speeds and step into it just starts to slowing speed up.
    Can anyone help in the wiring for this. Just want to make sure I hook it up right.
     
  2. jacques

    jacques Formula Junior

    May 23, 2006
    876
    Los Angeles/Florida
    Shift points on the T400 trans can be adjusted to a certain extent visa-vi the vacuum module on the bottom right side of the trans with a small screwdriver. We're talking 1/8th turns here mind you, and don't even think of removing/ replacing it without a pan under it, and with a replacement module in your other hand at the ready to screw it in. The gaskets to fail occasionally. The module is secured in place by an "L" bracket. The module is extremely common and costs<$20> USD. In my experience, the long three foot long tube leading from the gold colored vacuum multiplier on the top right side of the engine to the vacuum modulator needs is totally rotten from end to end and that is what is effecting shifting/points. It is most likely laying directly on top of back end of the engine and near the exhaust. I replaced that section of the rubber tube with aluminum tubing, with rubber tubing an both ends. I hope that this is of some help. Jq.
     
  3. 180 Out

    180 Out Formula 3

    Jan 4, 2012
    1,206
    San Leandro, CA
    Full Name:
    Bill Henley
    Question to Jacques: do you have a part number for the correct modulator? TIA!!!
     
  4. It's Ross

    It's Ross Formula 3

    Jul 30, 2007
    2,028
    Barrington, Ill. USA
    Full Name:
    Ross
    The wires need to be connected to that switch for a full throttle downshift which is electrically commanded on this transmission.
    The switch is normally open and closes on WOT
     
  5. jacques

    jacques Formula Junior

    May 23, 2006
    876
    Los Angeles/Florida
    No, I do not have the modulator part #. However, it is an extremely common part, and all parts houses have them in stock. Just take a quick look at your modulator so that you will know it when you see it. Just make sure that you buy the one with the adjustable deeply inset screw. These are preset, and you should begin driving the car at this point before you start your adjustments of 1/8th turns each time. these transmissions are very finely engineered instruments, that just don't get the respect, like Rodney D. Just like the dipstick markings: the distance between "add" and "full" equals one pint, or I/2 quart. Never ever over fill this tranny or you can easily blow the seals. I hope that this is of some value to you. Jq.
     
  6. zman

    zman Formula Junior

    Jan 14, 2006
    356
    Toronto, Ontario
    Hi Ross,
    Any reason why it would have been disconnected and which is proper way to wire it
     
  7. 180 Out

    180 Out Formula 3

    Jan 4, 2012
    1,206
    San Leandro, CA
    Full Name:
    Bill Henley
    I'm going to assume we're talking about the kickdown solenoid circuit. I was just looking at this system on my '83 auto, because my tranny suddenly lost the feature of kicking down from third to second when I mash the accelerator. My car's problem was that the microswitch was not working. But anyway, I found that the forward screw on the microswitch is the hot post, i.e., it gets voltage when the key is in the run position. The wire to the other screw leads to a single spade connector on the driver side of the transmission, toward the rear of the part of the housing that the pan bolts too, just above where there's a curve in the pan.

    I can't guess why anyone would disconnect the microswitch. Maybe the switch is shorted and it kept blowing a fuse. But without a functioning kickdown solenoid your tranny will not kickdown from 3rd to 2nd.

    I just bought a lot of four microswitches on eBay for $23, shipped, that I hope will work. They're Honeywell BZ-2RW82255-A2-S. If this unit works on my car, and if you need one, I'd be happy to share.
     
  8. jacques

    jacques Formula Junior

    May 23, 2006
    876
    Los Angeles/Florida
    As you all know, internal shift points in the 400 tranny are determined by pressure, which is governed by vacuum which is governed by the adjustable vacuum modulator. The kick-down is an in-or out function . This point can be varied by the positioning of the microswitch arm roller in relationship to the throttle arm that pushes on it, thus giving the option of when you want actual kick-down without having to "floor" the gas pedal. This is of course, a purely subjective option and a function of your shifting preferences. I was never completely pleased until a street shift kit was installed, thus transforming the 400i into an actual Ferrari. I hope that this is of some use. Thanks. Jq.
     
  9. It's Ross

    It's Ross Formula 3

    Jul 30, 2007
    2,028
    Barrington, Ill. USA
    Full Name:
    Ross
    I cannot imagine a reason to deliberately disconnect the switch unless it is shorted causing the trans to believe you are always under WOT. This is simple enough to check with an ohm meter, should be normally open and closed at WOT. If defective remember this is a standard electrical part available for peanuts at your local industrial supply house. NO need to further enrich the Modenese.
    Polarity shouldn't matter as it is a simple single pole single throw(on/off) switch. Check that one of the terminals isn't also grounded as you never know what those folks in Modena have done. Mine isn't handy to compare, perhaps others can advise also.
     

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