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Holding speed at tranny shift point

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    Holding speed at tranny shift point

    We had our first automatic overdrive transmission with the purchase of a new 1982 LTD. In the case of that car and every other one up to and including our current 1996 Grand Marquis with 133k miles, when you are in traffic and have to hold a speed that is right at the point where the transmission wants to shift up or down you get a rattling/clattering noise. If you are able to press down on the accelerator or brake slightly, it will go away. I had a 1978 LTD II with the 302 and the C4 and that transmission did the same thing. But older Fords, even with the C4, did not do that. For example, we had a 1974 Torino for 14 years. That had the 302 and C4. Never did that. But the newer ones have always done that, right from the time they were new.

    What did Ford do to cause this problem that did not exist before? Most of the time, it happens whether in automatic overdrive OR clicked out into regular drive with these transmissions. And for all of the emphasis on computers and high-tech, the change from vacuum-shifted to electronic controls did not include anything to eliminate the problem.

    Thoughts?

    Just as a bit of an addendum: That 1982 LTD had the 302 and the 7200 variable-venturi carb. When making a slow-speed turn into the garage, the engine would frequently stall. You could start it right back up again, but if the wheels were turned then the moment that you put the car into drive the engine would immediately stall. It would do that all day repeatedly unless you straightened out the wheels and then started the engine and shifted into drive. I was actually failed out of my first driver's test not because of any fault of mine, but just because you could NOT parallel park that car because it would not stay running when the wheels were turned while attempting to park. Over the years, the car would also stall at unexpected times in traffic. We had the car in the shop repeatedly and the carb was always being adjusted, to no avail. We eventually got rid of the car after 9 years and 27,000 miles. We just never had any confidence in the car and it's a wonder we kept it as long as we did. Years later, I read that the 'proper' starting procedure was to turn the ignition to ON before pressing down on the accelerator. My parents had always pressed down on the accelerator and then turned the ignition to START. I've wondered if that caused a problem with the carb. But I've talked with a fair share of people who have said they used the latter starting procedure with Ford carbs and had no problems.

    Any insights would be appreciated.
    Last edited by fordnmerc; 12-04-2015, 05:06 PM.
    David
    1989 LTD Crown Victoria LX
    14 previous Panthers, gone but not forgotten....

    #2
    The 4th speed is generally a higher drive ratio which makes things more susceptible to lugging. I believe the 4th gear is locked in for even more efficiency as opposed to the other gears which are not. So you get a little slop/cushion with the hydraulics on the 1st 3 gears but none in 4th.

    I hope others with more intimate knowledge of transmissions weigh in.

    Though I have to say I think ford aod transmissions in general shift very well. Only on the later AODW's (?) do I sometimes need to lock out 4th if I am in traffic that is about at the shift point.

    I wonder if a judicious adjustment of the kickdown/transmission pressure might be good for you.

    Jay
    Last edited by jaywish; 12-04-2015, 06:58 PM.
    03 Marauder DPB, HS, 6disk, Organizer Mods> LED's in & Out, M&Z rear control arms, Oil deflector, U-Haul Trans Pan, Blue Fuzzy Dice
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      #3
      the 96 should have a electronic lockup which means shifting into OD should be smooth, though the lockup will occur after that so it may feel like it shifts again. If you let your foot off the gas, it will unlock. If you tap the brake, it will unlock. If you put the pedal down by much, it will unlock. If it does it under cruise control on flat land, then you may have a transmission issue. As for the noise... if you are in OD at about 40mph and it chatters... this could be the dreaded AODE/4R7Xw shudder problem and will need a transmission rebuild, torque converter and to solve the problem, j-mod.

      Only two things are infinite, the universe and human stupidity, and I'm not sure about the former. -- Albert Einstein
      rides: 93 Crown Vic LX (The Red Velvet Cake), 2000 Crown Vic base model (Sandy), 2003 Expedition (the vacation beast)
      Originally posted by gadget73
      ... and it should all work like magic and unicorns and stuff.
      Originally posted by dmccaig
      Overhead, some poor bastards are flying in airplanes.

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        #4
        yeah, sounds like converter shudder. Usual fix is to service the trans and change it to Mercon V. Doesn't always fix it, but its the place to start rather than having the trans overhauled.

        The AOD didn't have a clutch in the torque converter, that was new with the AODE in 1992. Shudder is not possible with the AOD due to the way it bypasses the converter rather than locking it, and the C4 didn't lock the converter so no issue there either.
        86 Lincoln Town Car (Galactica).
        5.0 HO, CompCams XE258,Scorpion 1.72 roller rockers, 3.55 K code rear, tow package, BHPerformance ported E7 heads, Tmoss Explorer intake, 65mm throttle body, Hedman 1 5/8" headers, 2.5" dual exhaust, ASP underdrive pulley

        91 Lincoln Mark VII LSC grandpa spec white and cranberry

        1984 Lincoln Continental TurboDiesel - rolls coal

        Originally posted by phayzer5
        I drive a Lincoln. I can't be bothered to shift like the peasants and rabble rousers

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