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    1984 AOD Hard Shift

    New to the forum, can't believe there's a whole forum just for the Grand Marquis, awesome!

    I'm helping a friend with her 1984 with the 5.0 and AOD. It shifts very hard from park into drive and reverse and also shifts very hard from first to second. Haven't personally driven it fast enough to see about the 2-3 and 3-4 shifts. She just had a shop change the transmission fluid and filter and they seriously overfilled the transmission. It's an inch or two above the full line. Going to siphon it out to get it back down to the proper level this weekend and not driving it anymore until that's done. She also said that the car started stalling when going very slow or coming to a stop. This was only after the shop changed (and overfilled) the transmission fluid.

    Questions:
    Will overfilling the transmission by that much damage it? I'll measure how much extra comes out when I siphon it.

    Will having too much fluid in the transmission cause it to stall? Perhaps not allowing the transmission to disengage from the engine?

    Are there any typical reasons that would cause a hard shift as described? That was the original reason she brought it to a shop to have the transmission fluid and filter changed.

    I'll update what the transmission feels like after the fluid is at the correct level.
    Any input is greatly appreciated. Thanks in advance.

    #2
    Hi, welcome!

    A couple points worth noting:
    1984 will have a carb, or central fuel injection aka CFI aka TBI. In either case, there is a mechanical input to the transmission called the Throttle Valve linkage. It is a metal rod similar in design to a kickdown rod, but it works a little different from a kickdown rod. This is on the driver side of the carb or CFI unit. This modulates line pressure in the trans based on accelerator pedal position. Closed throttle, soft early shifts and easy engagement. Full throttle, firm late shifts with jerky engagement.

    You should check to see if the rod is maybe stuck in the full throttle position, or if it has come undone and has become stuck partially pushed down (tangled in nearby hoses or cables). If it is anywhere beyond the normal closed throttle position, it is normal for gear engagement to be very firm (alarmingly so). Proper adjustment of the TV linkage is important; too little/too soft will cause the trans to wear at an extremely accelerated rate and fail quickly. Too much/too firm will be unpleasant to drive. If the pressure is significantly too high, it may refuse to do a 2-3 shift at all, and just stay in 2 forever or until a very high speed. I find the linkage binds up a bit and needs to be lubricated periodically at both the trans end and the pivot point beside the throttle cable; it will get stuck behaving like yours if I don't do this a couple times a year.

    Next point: AOD fluid level must be checked with the fluid at operating temp (as it expands), and with the engine idling as the fluid level marks are designed assuming fluid is currently filling all the passages of the trans. It is normal for the fluid level to seem overfilled when the engine is off. When the engine is running and fluid is cold, it may seem slightly low. It's therefore important to check when hot and still idling. Pass the shifter through all positions then back into park before checking it.

    Current driver: Ranger
    Panthers: 83 GM 2dr | 84 TC | 85 CS
    | 88 TC | 91 GM
    Not Panthers: 85 Ranger | Ranger trailer | 91 Acclaim | 05 Focus
    Gone: 97 CV | 83 TC | 04 Focus | 86 GM
    | Junkyards

    Comment


      #3
      is the idle speed reasonable? High idle makes for hard engagement out of park. There is a mechanical high idle system on the passenger side of the CFI unit. If that is stuck or if the heater or choke pulloff isn't working to lift it out, the idle will be too fast.

      otherwise hard shifts between gears is usually something with the TV rod. If its unhooked and jammed to high pressure, or if someone has messed with the adjustment incorrectly that might do it. There is meant to be a plastic or bronze bushing between the rod and the pin it sits on, if that fell apart things can get funny too.
      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

      Comment


        #4
        Thanks for the quick replies! I was a bit concerned when I realized that the last post in the Transmission sub-forum was about six months ago.

        Originally posted by kishy View Post
        Hi, welcome!

        A couple points worth noting:
        1984 will have a carb, or central fuel injection aka CFI aka TBI. In either case, there is a mechanical input to the transmission called the Throttle Valve linkage. It is a metal rod similar in design to a kickdown rod, but it works a little different from a kickdown rod. This is on the driver side of the carb or CFI unit. This modulates line pressure in the trans based on accelerator pedal position. Closed throttle, soft early shifts and easy engagement. Full throttle, firm late shifts with jerky engagement.

        You should check to see if the rod is maybe stuck in the full throttle position, or if it has come undone and has become stuck partially pushed down (tangled in nearby hoses or cables). If it is anywhere beyond the normal closed throttle position, it is normal for gear engagement to be very firm (alarmingly so). Proper adjustment of the TV linkage is important; too little/too soft will cause the trans to wear at an extremely accelerated rate and fail quickly. Too much/too firm will be unpleasant to drive. If the pressure is significantly too high, it may refuse to do a 2-3 shift at all, and just stay in 2 forever or until a very high speed. I find the linkage binds up a bit and needs to be lubricated periodically at both the trans end and the pivot point beside the throttle cable; it will get stuck behaving like yours if I don't do this a couple times a year.

        Next point: AOD fluid level must be checked with the fluid at operating temp (as it expands), and with the engine idling as the fluid level marks are designed assuming fluid is currently filling all the passages of the trans. It is normal for the fluid level to seem overfilled when the engine is off. When the engine is running and fluid is cold, it may seem slightly low. It's therefore important to check when hot and still idling. Pass the shifter through all positions then back into park before checking it.
        You're correct, it's 2 barrel TBI and there is indeed a TV linkage on the drivers side. The linkage moves freely though. I can easily see the linkage rod, which looks like a bent up 1/2 inch aluminum pipe, and it goes all the way down to the transmission, just beside the exhaust, where it connects to a lever sticking out of the transmission. Moving the rod moves the lever and there's nothing snagging, sticking or binding up. I was actually disappointed to see that it moved freely because your description of a malfunctioning TV linkage matches how the car acts just about perfectly.

        While driving it around this evening it always felt like the engine was revving much too high before the transmission would shift. The 1-2 shift is so hard that it almost feels like the car is being hit from behind. The 2-3 shift isn't nearly as hard but it's also not soft and it also feels to be late. The shift to OD is also rough, somewhere between the sledge hammer of 1-2 and the almost acceptable 2-3. The only time any shift felt acceptable was when I was deep in the throttle, accelerating from a stop, and then the 2-3 shift felt like a good smooth-but-firm shift, but 1-2 was still sledgehammer hard, much harder than I would expect even from a full throttle acceleration.

        Earlier I did check the transmission fluid when it was warm and with the engine running on level ground. I let it idle for a few minutes and then drove it around the block for 5 or 10 minutes before checking it, which was when I got the extremely high reading. I siphoned out almost a quart just now and after a spirited 25 minute drive around town it was fully hot and reading just barely over the last line where the X's stop. So it was about 1 quart too high when the car was brought to me this morning. Unfortunately, there was no change in behavior between then and now.

        Originally posted by gadget73 View Post
        is the idle speed reasonable? High idle makes for hard engagement out of park. There is a mechanical high idle system on the passenger side of the CFI unit. If that is stuck or if the heater or choke pulloff isn't working to lift it out, the idle will be too fast.

        otherwise hard shifts between gears is usually something with the TV rod. If its unhooked and jammed to high pressure, or if someone has messed with the adjustment incorrectly that might do it. There is meant to be a plastic or bronze bushing between the rod and the pin it sits on, if that fell apart things can get funny too.
        I think you're right that the hard shift into drive and reverse is due to a high idle when cold. I'm not used to cars this old anymore and it seems to take longer than 5 minutes to warm up (I live in South Florida). But once fully warmed up after a 20 minute drive it shifts seemingly properly into drive and reverse... usually. Sometimes it decides to idle a bit high again and then it sledgehammers into drive.

        Also, once it warmed up I experienced what my friend described about it stalling, or wanting to stall, when coming to a stop. It never completely stalled on me, but several times it would almost stall and then catch itself just as I came to a stop. After that the idle would be a bit high again until it decided not to be. I'll check the mechanical idle system tomorrow. I'm not sure what a heater or choke pulloff is though.

        The plastic bushing on the TV rod is intact and looks good. The adjustment screw for the TV rod where it hits against the throttle lever is all the way backed out, so it's as low as it can go, or as far forward as it can go, depending on how you look at it. Could there be a problem with whatever the TV rod is moving inside the transmission? And if so, can it be adjusted/fixed by just taking the transmission pan off? Or could there be another culprit? I'm not sure if it's related, probably not, but the gear indicator on the dashboard is not lined up with the gear it's actually in, it's always high. High enough that OD is actually at the bottom of the N and it won't even touch the 1 on the indicator when in 1st gear.

        Regarding the stalling, it may be prudent to note that the shop she took it to also replaced the MAP sensor for a code 14, replaced the EGR valve and EVP sensor for code 31, and replaced the fuel filter for code 41. Before that work was done it did not have stalling or near stalling issues, though it did shift hard before that.

        Thanks again for your help. My friend was rather disheartened to put over $1000 into it at the shop, only to have it come back in worse condition.

        Comment


          #5
          The heater looks like a hockey puck with wires plugged into it. If its not connected or just dead, it won't heat up and allow the high idle to drop out.

          The pulloff is a small vacuum thing at the rear of the unit, right behind the heater. Essentially they fight one another. The vacuum pull-off does what the name implies, it tries to pull the high idle cam out of the way to drop the idle. The spring in the choke heater holds it in position. As the heater warms up, the spring gets weaker until the vacuum pull-off overcomes it and pulls the high idle cam out of the way. In the middle of it all are a few linkage bits that need to not be gummy. Mostly the pulloff needs to move if you apply vacuum and it needs to hold vacuum. I don't remember if these have a vac hose you can actually connect to or not. The choke heater needs to see ~8v or something when the engine is running, and an ohm check should show a few ohms resistance if good.


          the annoying part about these cars is they're old enough that people don't know how to work on them anymore. Might want to find out of the shop messed with the trans adjustments. There is an official procedure involving a drill bit of some size and a pressure gauge to set it if needed. It might not be a terrible idea to do that just to get it to a known correct point.

          https://documents.holley.com/114501.pdf

          has the process. You want #4 for the gauge and drill method.


          if the egr valve didn't open for a long time and now it does, its possible a nugget of carbon came loose and has it stuck slightly open. Might be worth removing the valve and making sure its clear underneath and fully closed.
          Last edited by gadget73; 03-29-2020, 01:25 AM.
          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

          Comment


            #6
            There is adjustment for the gear pointer built into the steering column shaft.

            It is a while collar clamped around the steering shaft with a cable strung through it that attaches to the shift tube. The other end of the cable attaches to the gauge cluster.

            The white collar has a small fastener you can loosen and then spin the collar to match up the pointer to what gear you are in.

            Wont line up perfectly for all gears but you should be able to get it better.

            This adjustment has absolutely no bearing on what gear your transmission is actually in. It is just taking the motion of the shift tube and displaying it through an adjustable mount onto your gauge cluster.

            These white collars are prone to plastic fatigue and disintegrate without warning.

            Another issue is the black plastic mount for the cable that attaches to the shift tube. That can break as well.

            I recommend warming up the plastic collar with a heat gun some before attempting to loosen the fastener for any adjustments.
            ~David~

            My 1987 Crown Victoria Coupe: The Brown Blob
            My 2004 Mercedes Benz E320:The Benz

            Originally posted by ootdega
            My life is a long series of "nevermind" and "I guess not."

            Originally posted by DerekTheGreat
            But, that's just coming from me, this site's biggest pessimist. Best of luck

            Originally posted by gadget73
            my car starts and it has AC. Yours doesn't start and it has no AC. Seems obvious to me.




            Comment


              #7
              if the collar is already cracked, a zip tie will usually serve to hold it together so it functions again.
              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

              Comment


                #8
                Originally posted by 87gtVIC View Post
                This adjustment has absolutely no bearing on what gear your transmission is actually in. It is just taking the motion of the shift tube and displaying it through an adjustable mount onto your gauge cluster.
                If the shifter position indicator doesn't have any bearing on actually shifting then I'm going to leave it alone for now. Cracking plastic pieces is pretty much a guarantee here in Florida. If I get really picky I may try to adjust it after everything else is squared away. Thanks for the info.

                Originally posted by gadget73 View Post
                The heater looks like a hockey puck with wires plugged into it. If its not connected or just dead, it won't heat up and allow the high idle to drop out.

                The pulloff is a small vacuum thing at the rear of the unit, right behind the heater. Essentially they fight one another. The vacuum pull-off does what the name implies, it tries to pull the high idle cam out of the way to drop the idle. The spring in the choke heater holds it in position. As the heater warms up, the spring gets weaker until the vacuum pull-off overcomes it and pulls the high idle cam out of the way. In the middle of it all are a few linkage bits that need to not be gummy. Mostly the pulloff needs to move if you apply vacuum and it needs to hold vacuum. I don't remember if these have a vac hose you can actually connect to or not. The choke heater needs to see ~8v or something when the engine is running, and an ohm check should show a few ohms resistance if good.


                the annoying part about these cars is they're old enough that people don't know how to work on them anymore. Might want to find out of the shop messed with the trans adjustments. There is an official procedure involving a drill bit of some size and a pressure gauge to set it if needed. It might not be a terrible idea to do that just to get it to a known correct point.

                https://documents.holley.com/114501.pdf

                has the process. You want #4 for the gauge and drill method.


                if the egr valve didn't open for a long time and now it does, its possible a nugget of carbon came loose and has it stuck slightly open. Might be worth removing the valve and making sure its clear underneath and fully closed.
                Regarding the TV rod position, I read the pdf file on how to adjust it. I can't complete the full adjustment because I don't have a pressure gauge or the proper fitting, but I understand how to adjust the rod itself, and the rod does indeed seem to be MUCH too far back/down. The instructions say to set the screw at the top, then loosen the trunnion holding the rod at the bottom at the transmission lever, then move the lever all the way up until it stops while the TV rod stays up. So this is effectively making sure that the TV rod is hard against its stop while the lever on the transmission is also hard against its stop. I disconnected the TV rod at the top to see how much farther up the transmission lever would go and the rod ended up moving over an inch past where it connects to the CFI linkage. Here's a picture for a better idea.
                Click image for larger version

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                If I understand things correctly, this means the the TV rod needs to be adjusted via the trunnion at the lever on the transmission, because currently when the TV rod is at it's stop at the throttle plate, the lever at the transmission is not even close to being at it's internal stop. Please correct me if I'm wrong.

                I found the heater hockey puck and everything appears to be ok there, nothing gummed up. Here's what I was looking at.
                Click image for larger version

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                I didn't test it yet because upon starting it up after sitting for 48 hours it's exhibiting a new problem, possibly related to the stalling/near stalling when coming to a stop. At first, the engine stalled immediately after starting, and then after a hard start it sputtered pretty bad. I don't know how to explain it so I'll include two videos instead of a paragraph of unintelligible text.

                https://vimeo.com/402401475 https://vimeo.com/402401281

                To me it sounds like there's air in the fuel lines, but I'm sure that's not it. It has just over a 1/4 tank of gas and is sitting on level ground. When it's not sputtering it runs very smooth. This may have something to do with why my friend couldn't get it to start at first on the morning that she brought it over. I'll see about checking the high idle/heater choke thing tomorrow as well as the parts that the shop replaced.

                Also, in the picture of the TV linkage, there is a part there that has a plunger and also seems to control idle. It's what the throttle linkage stops against. It looks like it has a vacuum line going to it and a sticker on it that ends in 957-AB. Is that something that could possibly cause a high idle as well? It moves and if I give it a push it goes down and the idle goes down, sometimes it stays there, sometimes it doesn't.

                Comment


                  #9
                  full TV pressure at full throttle is probably not far off. My cars with cables all end up pretty near to that point at least. If the trans hits full travel before the throttle body opens full, the pressure is way too high and the shifts will be late and hard.


                  kinda sounds like a vacuum leak. If the MAP sensor in particular sees low vacuum it will over-fuel and things run generally like garbage. Bad MAP does stuff like that too, but checking all of the vacuum lines is something these are old enough to need anyway. Could also be a flaky connection somewhere. Might be worth making sure the connector at the front of the CFI unit is clean and tight. If the injectors are randomly losing contact things get funky.
                  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

                  Comment


                    #10
                    The TV rod was definitely the problem with the transmission. I adjusted it according to the instructions in that pdf file and now it shifts about like it should. The 1-2 shift still feels a little bit hard, but better too firm than too soft from what I've read. The lever on the transmission was definitely hitting its full open position before the throttle was full open because the TV rod was binding up when close to full throttle. I can't set it so that the throttle and the transmission lever hit full open at the same time because the transmission lever, via the TV rod, has much more travel than the throttle. If I set them both according to their max then I still get a half sledgehammer 1-2 shift. Maybe that's why they switched from a rod to a cable on the later cars.

                    As for the stalling and running rough, it's definitely something electrical on the top of the engine. Today it was doing it pretty badly again, enough that the car was bucking while I was trying drive it to test the transmission. I gave all the wires, plugs, connections, etc, a good wiggle, tug/shove, started it back up and it went away. I did check the vacuum lines and they all look very good. I doubt any of them are original because not a single vacuum line that I saw had even a small crack in it. The car only has 133,000 miles on it and apparently the previous owner maintained it very well.

                    Thanks a whole bunch for the help guys. Having the transmission shifting smoothly again is a huge load off my mind.

                    Comment


                      #11
                      Dont be afraid of doing the wire wiggle test while the car is running. Can help you nail down an issue as you will immediately find a result..that is if any symptoms show themselves during idling.

                      Feel free to smack the transmission shop tech aside the head. This is why I do all of my own work.
                      ~David~

                      My 1987 Crown Victoria Coupe: The Brown Blob
                      My 2004 Mercedes Benz E320:The Benz

                      Originally posted by ootdega
                      My life is a long series of "nevermind" and "I guess not."

                      Originally posted by DerekTheGreat
                      But, that's just coming from me, this site's biggest pessimist. Best of luck

                      Originally posted by gadget73
                      my car starts and it has AC. Yours doesn't start and it has no AC. Seems obvious to me.




                      Comment


                        #12
                        Yeah, why can't those guys EVER seem to fill the damn things correctly? It's not that hard if even I can manage it.. Sheesh.

                        Plugged EGR is what my '85 CFI car was plagued with. That and some vacuum lines were routed incorrectly despite the routing being on the damn fan shroud. Mileage isn't a problem with those guys, it's age. I'd still be leery of them, especially a car that lived in Florida. Give 'em the ole sniff of propane or whatever suits your fancy at idle to see if engine speed picks up at all, especially at the rubber elbows. I miss my '85, I'd like to find another like it. I don't say that about too many cars I've owned, too.
                        1985 LTD Crown Victoria - SOLD
                        1988 Town Car Signature - Current Party Barge

                        Comment


                          #13
                          yep, age and heat are not on your side here.

                          Might not be a waste of time to just unplug every electrical connector and gently re-tension the contacts. Anything thats corroded would want a good cleaning and a bit of dielectric grease applied. The ones with original grease probably wouldn't mind having it flushed and replaced either. It gets very hard after a while. I've had to dig it out of light bulb sockets just to get the bulbs to function again. The electrical bits on these things honestly were not amazing 35 years ago and time hasn't improved that either.

                          maybe the TV travel on the rod cars is more than the cable rig, don't know. Haven't really spent lots of time around them, but either way good to know you've got reasonable shifting after an adjustment.
                          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

                          Comment


                            #14
                            I checked all the vacuum lines, found one that had a partial kink in it, fixed that, other than that they're all good. Replaced the plug wires because two came apart when I took them off to check them. Cleaned and checked several electrical connections. Still doesn't run right, intermittently. Today it ran well at first then once it warmed up it started getting worse until it stalled and wouldn't start back up for a while. Then after 20 minutes or so it started right up. A friend of mine who had an 88 GM said it could be the ignition control module. Might give that a shot, though prices on those vary wildly.

                            Also thinking I should maybe start a new thread for this engine issue cause currently this thread is in the transmission sub-forum.

                            Comment


                              #15
                              If you have a TFI Module change it it is located on the Distributor they are world famous for failure at a most inoppertune time. Yes it sounds like that it is the Ignition Module. Had that happen to me, just read in the tech section of my story.

                              Comment

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