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AOD TV Pressure High in Neutral, Transmission Shifts Like the TV Pressure is Low

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    AOD TV Pressure High in Neutral, Transmission Shifts Like the TV Pressure is Low

    Just got done scanning down through this Transmission thread...can't find anything that resembles the problem I'm having. Here goes:
    I had the transmission overhauled in my 88 Town Car over the winter by my uncle, who was a Ford certified tech and automatic transmission specialist for over 40 years. I removed it from the car and brought it to him, he tore it down and rebuilt it using a combination of new parts, parts from my old transmission and some more from transmissions he had around his shop. I bought a new B&M Tork Master 2000 RPM stall converter and also installed a cooler in front of the radiator for some extra insurance. FWIW, my original AOD case was cracked around the bellhousing (I suspect it was due to the extra-long driveshaft crammed way too tight between the transmission and rear axle, that problem is featured in another thread) so the "new" transmission case is from an 83 T-Bird. All new gaskets and seals internal and external, valve body was done, new OD band, filter. Remainder of parts were best selected from the three different AODs that were combined to make one.

    He calls me and tells me the transmission is ready, so I go pick it up. I bring it home, put a lick of paint on it and put it into the car. It goes in relatively well, no clearance issues with the flex plate and converter or anything else like that. Filled it up with ATF, cycle the gears, seems to be good. Checked TV pressure once warmed up, right on the money at 35 PSI in park with no cable adjustment, simply connected as-is.

    Take it for a test run, the shifting is all kinds of messed up. No 1-2 shift at first, when it finally did upshift into 2nd, then the 2-3 and 3-4 were mushy as shit and piled up.

    Figured it was just bawky from being freshly built. I go home, double check the TV pressure in NEUTRAL this time, bang on at 35 PSI. As the 1-2 shift was so delayed and a bit harsh, I drop the pressure to 30 PSI. Take it for another test run and wouldn't you know, it was behaving like there was zero TV pressure. Early, soft, mushy shifts, no downshifting at all under WOT, starting off in 2nd gear, etc.

    Go home again, check TV pressure in neutral, bang-on 30 PSI. Based on how it was acting at 30 PSI, I shorten the cable to bump the TV pressure to 40 PSI.

    Another road test, another complete failure, albeit a bit better than at 30 PSI. Upshifts are OK, (though not enough 'slip-bump' for my liking) won't go into OD at WOT, but no forced downshifting at any speed from any gear. Still acting like the TV pressure is too low. I verify the TV pressure to be 40 PSI at idle in neutral with the block on the cable between the crimped slug at the end and the square plastic adjustment sleeve. With it removed (when spec is between 0-5 PSI) my transmission is running closer to 30 PSI.

    I get pissed off with it, pull the cable so short as it will go. Lock the white tab in, TV pressure is showing >50 PSI at idle now (no block). Revving makes it go in excess of 80 PSI. I then remove the gauge, road test again. This time the 1-2 shift is perfect, but 2-3 is still too early/soft. 3-4 backout shift happens at just under 35 MPH. Light throttle 3-4 shift happens just under 40 MPH. At 50-60 MPH 3-4-3-4-3-4 shift hunting on a slight grade is brutal. A forced 3-2 downshift will not happen over 15 MPH, making for some pretty embarrassing trips up steep hills, unless I do the AOD shuffle and manually haul it down into low gear. 2-3 shifts are almost immediately after the 1-2 shift at about 20 MPH unless I got the hammer down.

    Has anyone else encountered this type of behaviour from an AOD? My next step is to set up the TV pressure gauge and leave it in place while I drive, just to observe what it does as it's acting like the TV pressure is dropping drastically once the transmission is placed into gear. Not that it will really prove anything, as all the specs for TV pressure are given for when the car is hot idling in neutral...

    I really don't feel like taking that transmission out again...I only just got the rust, dirt and crap out of my eyes from putting it back in Easter weekend. Sick of doing everything right and still not being able to make something work as it should, and having to do stuff over and over and over again...

    Fluid level is good, if anything might be slightly overfull. No leaks. Engine is running very nicely, FWIW it's an HO converted 5.0. Upper intake is stock, EGR spacer is bored out to 58 mm to match the 86 Mustang TB, which has the throttle linkage flipped. Old transmission wasn't like this, if anything it built up too much TV pressure and had delayed/harsh upshifts, no slippage unless it was cold and slightly overfull on fluid, and was noisy in gear. Glad I addressed it when I did, as the case was almost split in two from the crack along the bellhousing. Much longer and it probably would have broken in two and left me stranded on the side of the road like an asshole.
    Summer car-> 1988 Lincoln Town Car, triple blue, 335,xxx km. New HO 5.0 in and running. Bought 2006/08/22. June 2017 PotM!
    Winter vehicle-> 1995 Ford F-250 XLT SuperCab 4x4, 284,xxx+km. AKA "Brutus" 460/E4OD/4.10 axles and 12 MPG. Bought 2019/08/14

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

    #2
    Something is wrong internally. Whether that’s a spec of dirt hanging up a shift valve or the governor, a check ball in the wrong place I have no idea. I wouldn’t drive it until you figure it out.

    I have a book on the AOD and I am trying to find out what and how. There is a pressure problem for sure. It seems you have the TV pressure in 1st, but lose it once out of first. It sure what would cause that but I’ll think on it. Line pressure is the other side of the pressure equation. It would be worth a look to see what that is doing. If that is too high, maybe it’s pushing the 2-3 and 3-4 shift valves to short shift. What would cause that, I have no idea.

    Might and to send 88grandmarq a PM.
    1990 Country Squire - weekend cruiser, next project
    1988 Crown Vic LTD Wagon - waiting in the wings

    GMN Box Panther History
    Box Panther Horsepower and Torque Ratings
    Box Panther Production Numbers

    Comment


      #3
      Originally posted by Tiggie View Post
      Something is wrong internally. Whether that’s a spec of dirt hanging up a shift valve or the governor, a check ball in the wrong place I have no idea. I wouldn’t drive it until you figure it out.

      I have a book on the AOD and I am trying to find out what and how. There is a pressure problem for sure. It seems you have the TV pressure in 1st, but lose it once out of first. It sure what would cause that but I’ll think on it. Line pressure is the other side of the pressure equation. It would be worth a look to see what that is doing. If that is too high, maybe it’s pushing the 2-3 and 3-4 shift valves to short shift. What would cause that, I have no idea.

      Might and to send 88grandmarq a PM.
      I did get a tiny piece of brass lost in the TV port when hooking up my gauge once. Maybe that's what's causing my trouble? i would think an obstruction in the TV passage would cause low pressure in all gears...maybe it's still making pressure but blocking something in the valve body or messing with the governor?

      I'm going to try changing my fluid and *hope* the debris comes out when it's drained.

      Wish me luck.
      Summer car-> 1988 Lincoln Town Car, triple blue, 335,xxx km. New HO 5.0 in and running. Bought 2006/08/22. June 2017 PotM!
      Winter vehicle-> 1995 Ford F-250 XLT SuperCab 4x4, 284,xxx+km. AKA "Brutus" 460/E4OD/4.10 axles and 12 MPG. Bought 2019/08/14

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

      Comment


        #4
        What valve body did he use? There are basically two cases for these, the 80-85 one and the 86+ one. Difference is the early ones have a 3-4 accumulator in the case, late do not. The valve bodies don't interchange between them, but I won't admit to actually knowing what happens if you get that mixed up.


        Sounds like you have the pressure right if its ~35 with the gauge and 0-5 without it. There is also a check in the book, which I don't have in front of me, that says what you should get with the TV pulled all the way out at idle. Sounds like the pressure is not increasing like it ought to be. Since its coming up with cable movement, the TV lever has to be engaged on the regulator valve inside but its possible something is wrong causing it to not increase as much as it should.

        Might have to hook the gauge up in such a way that you can monitor it while driving and see what it does vs what the manual says it should be doing. I suspect you'll find the line pressure is low for whatever reason, and I'll guess its something going on with the valve body. Could even be leakage between the body and the case. Sometimes the gaskets aren't really well made and can leak if not installed exactly so. Torque specs on the valve body are also very critical for things to work correctly. Its some fairly low number of inch-pounds and the torque pattern has to be followed.
        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


          #5
          Originally posted by gadget73 View Post
          What valve body did he use? There are basically two cases for these, the 80-85 one and the 86+ one. Difference is the early ones have a 3-4 accumulator in the case, late do not. The valve bodies don't interchange between them, but I won't admit to actually knowing what happens if you get that mixed up.


          Sounds like you have the pressure right if its ~35 with the gauge and 0-5 without it. There is also a check in the book, which I don't have in front of me, that says what you should get with the TV pulled all the way out at idle. Sounds like the pressure is not increasing like it ought to be. Since its coming up with cable movement, the TV lever has to be engaged on the regulator valve inside but its possible something is wrong causing it to not increase as much as it should.

          Might have to hook the gauge up in such a way that you can monitor it while driving and see what it does vs what the manual says it should be doing. I suspect you'll find the line pressure is low for whatever reason, and I'll guess its something going on with the valve body. Could even be leakage between the body and the case. Sometimes the gaskets aren't really well made and can leak if not installed exactly so. Torque specs on the valve body are also very critical for things to work correctly. Its some fairly low number of inch-pounds and the torque pattern has to be followed.
          I'm not sure which valve body he ended up using, I know he did overhaul the valve body prior to installation. I did get both variations of valve body gasket so he was sure to have one that was right.

          I'm leery about observing the gauge while driving, as there is not TV pressure spec for while driving or in a gear, for that matter. Unless the pressure is dropping to zero, I don't know what's an acceptable TV pressure. That may further cloud my judgement on this whole concern...

          He is very aware of bolt torque spec for the valve body and filter, he lectured me on that when changing filters in the past. 80-85 in. lbs. is the correct torque.

          I have the pan dropped again now and the filter is out, letting it drain, going to remove the valve body tomorrow and see what I can see up yonder.

          The more I think about it, the more I'm inclined towards the little chunk of brass that got into the TV port is causing me grief. I just need to figure out where the TV port goes within the transmission case and attempt to extract it. Hopefully it was big enough that it didn't make it far...
          Summer car-> 1988 Lincoln Town Car, triple blue, 335,xxx km. New HO 5.0 in and running. Bought 2006/08/22. June 2017 PotM!
          Winter vehicle-> 1995 Ford F-250 XLT SuperCab 4x4, 284,xxx+km. AKA "Brutus" 460/E4OD/4.10 axles and 12 MPG. Bought 2019/08/14

          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 stuff in the shop manual about what it should be under what conditions. I know I've looked at it, but the books are in the garage and I'm not at the moment.
            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


              #7
              Originally posted by gadget73 View Post
              there is stuff in the shop manual about what it should be under what conditions. I know I've looked at it, but the books are in the garage and I'm not at the moment.
              My books are for 1986 model year cars. I know 86 was an odd year, but my books also don't say anything about TV pressure during the road test. Says to adjust hot idling in neutral until 35 PSI (+/- 5 PSI) with block, < 5 PSI with block removed. Do not drive if PSI is lower than spec, road test to confirm.

              Which is what I've done, but like I said earlier, my road tests are resulting in the car acting like there is next to zero TV pressure.

              I still haven't dropped the valve body to investigate the insides further or to try to find the chunk of brass that went into the TV port, or done a line pressure test. If I can find and remove the foreign debris, I will then do the line pressure test and see what that's saying.

              Always something with this fu(king car, honest to God...
              Summer car-> 1988 Lincoln Town Car, triple blue, 335,xxx km. New HO 5.0 in and running. Bought 2006/08/22. June 2017 PotM!
              Winter vehicle-> 1995 Ford F-250 XLT SuperCab 4x4, 284,xxx+km. AKA "Brutus" 460/E4OD/4.10 axles and 12 MPG. Bought 2019/08/14

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

              Comment


                #8
                bah, 91 manual says "control pressure specs can be found in the special specifications booklet" which I do not have.

                looking over the trouble chart, all of it says low control pressure, sticky valve body, or governor problems.

                Gov check is to accel to 25 mph then completely back off the throttle. If it doesn't kick to third, the gov isn't working properly.

                84 manual has nothing trans related, my 85 powertrain manual just tells how to set the TV linkage and rebuild it. No troubleshooting or diag stuff. I didn't look at the 86 manual but its likely the same one you have.
                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


                  #9
                  Originally posted by gadget73 View Post
                  bah, 91 manual says "control pressure specs can be found in the special specifications booklet" which I do not have.

                  looking over the trouble chart, all of it says low control pressure, sticky valve body, or governor problems.

                  Gov check is to accel to 25 mph then completely back off the throttle. If it doesn't kick to third, the gov isn't working properly.

                  84 manual has nothing trans related, my 85 powertrain manual just tells how to set the TV linkage and rebuild it. No troubleshooting or diag stuff. I didn't look at the 86 manual but its likely the same one you have.
                  Thanks for the info.

                  I don't think I will have any trouble making it pass the governor test like that, as it upshifts too readily already. It's the downshifting (or lack thereof) that's concerning me.

                  Wasn't there a variation of box panther that had a '2nd gear lockout' to prevent engine overspeed? I'm thinking it may have been a police interceptor feature? Or am I totally out to lunch on that one?

                  I may get another governor and try it to see if it makes any difference. I did drop the valve body the other night, everything looked fine. I did get the chunk of brass out of an oil galley, and for kicks I pulled the 2-3 accumulator to have a look, as 2-3 and 3-2 shifts seem to be the worst affected. Everything looked great.

                  My transmission does have a 3-4 accumulator piston in the front left corner of the case, so I assume it has been built to an earlier model standard. Builder says he's stumped, figures a bottle of friction modifier MAY help.

                  It's never good when the tranny guy says to put additives into the transmission lol
                  Summer car-> 1988 Lincoln Town Car, triple blue, 335,xxx km. New HO 5.0 in and running. Bought 2006/08/22. June 2017 PotM!
                  Winter vehicle-> 1995 Ford F-250 XLT SuperCab 4x4, 284,xxx+km. AKA "Brutus" 460/E4OD/4.10 axles and 12 MPG. Bought 2019/08/14

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

                  Comment


                    #10
                    police cars had "2" as the lowest gear rather than "L". Different valve body.

                    may be worth getting hold of the special spec book and checking what exactly the line pressures are under what conditions. The trouble chart has stuff like if its low in this position but not that position, go here, look at that, etc. Also maybe post over at clickclickracing. They're AOD guys and might have more insight. I've never had my hands in one beyond changing a valve body.
                    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


                      #11
                      First casualty today from running it with too much TV pressure...output shaft housing seal blew out of the extension housing, slid back on the drive shaft yoke. Coated the underbelly of the car with ATF and made a fine cloud of smoke and droplets on my way home today.

                      I took the driveshaft out and put the seal back in. Before I reinstalled it, I put a thick coating of loctite on the mating surfaces of the seal and the transmission extension housing in an effort to help it stay in place.

                      I'm going to need a valvebody I think. Governor tests fine (drive it to 25 mph, back out the throttle, goes into 3rd). Only other thing it could be far as I can see.
                      Summer car-> 1988 Lincoln Town Car, triple blue, 335,xxx km. New HO 5.0 in and running. Bought 2006/08/22. June 2017 PotM!
                      Winter vehicle-> 1995 Ford F-250 XLT SuperCab 4x4, 284,xxx+km. AKA "Brutus" 460/E4OD/4.10 axles and 12 MPG. Bought 2019/08/14

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

                      Comment


                        #12
                        That seal should not actually be under any pressure. There is a vent in the case that is supposed to relieve any pressure from heat expansion though, might want to check that. Its a little button looking thing on the main case, right where the tailshaft bolts up.

                        is the bushing in the tailshaft any good? If thats really sloppy the drive shaft can move around and it might be enough to grab and yank the seal out. Rusty driveshaft yoke might also do it.

                        here's an off the wall thought, is it the proper dipstick and tube? I don't honestly know if there are multiple choices for the AOD besides the obviously goofy looking van one but I'm wondering if the fluid level is not actually correct because the dipstick lies. How much fluid went in on initial install? Should be pretty darn close to 3 gallons / ~11 liters for a completely dry trans and converter. If its more than 3.5 gallons I'd be concerned about the dipstick accuracy.
                        Last edited by gadget73; 05-06-2020, 10:37 PM.
                        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


                          #13
                          I don't remember seeing any vents on the main case when I put it into the car, it blows the dipstick out during sustained highway driving. Is it possible only later model AODs had the vent?

                          Very good point about the tailshaft bushing. I noted the tailshaft moved laterally significantly when the driveshaft was out to replace the seal. I also noticed significant driveline vibration at highway speeds as well, supports the tailshaft bushing being pooched theory.

                          Upon installation, the dry transmission took about 10-11 liters to fill. 4 liters, start and let it set settle. Then 4 more, let it run and top off with 2-3 more liters.

                          The dipstick is the one from the original transmission that came out of the car in 2008-2009, when that one had to be replaced. I kept it and replaced the O-ring in it over the winter while my transmission was sent off to be overhauled, so he didn't mix it up with a truck dipstick or anything like that.
                          Summer car-> 1988 Lincoln Town Car, triple blue, 335,xxx km. New HO 5.0 in and running. Bought 2006/08/22. June 2017 PotM!
                          Winter vehicle-> 1995 Ford F-250 XLT SuperCab 4x4, 284,xxx+km. AKA "Brutus" 460/E4OD/4.10 axles and 12 MPG. Bought 2019/08/14

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

                          Comment


                            #14
                            "I don't remember seeing any vents on the main case when I put it into the car, it blows the dipstick out during sustained highway driving. Is it possible only later model AODs had the vent?"

                            EDIT: I looked a a couple pictures I took of the transmission prior to installation, it does have a vent on the top back by the extension housing.
                            Summer car-> 1988 Lincoln Town Car, triple blue, 335,xxx km. New HO 5.0 in and running. Bought 2006/08/22. June 2017 PotM!
                            Winter vehicle-> 1995 Ford F-250 XLT SuperCab 4x4, 284,xxx+km. AKA "Brutus" 460/E4OD/4.10 axles and 12 MPG. Bought 2019/08/14

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

                            Comment


                              #15
                              I'm having balance issues after doing the aluminum driveshaft swap with a crap bushing. I read something about the aluminum driveshaft having a dot that is supposed to line up with a paint mark on the tailshaft. My driveshaft had blue and yellow dots, though I'm pretty sure the yellow is supposed to be used. I had seen the paint on the end of the tailshaft but had not been aware of its significance. I read about another type of car (possibly a Mustang) that is supposed to have a paint mark on the diff flange or wherever for the same purpose. I'm going to try repositioning the driveshaft before having the bushing dealt with (hopefully at a shop that has the tools to replace the bushing without removing the housing). I had trouble recently finding the source I had seen previously, but it must be out there somewhere. Not sure if that will be useful for you, but it might be something to consider.

                              2000 Grand Marquis LS HPP, a hand-me-down in 2008 with 128,000 km; 175,000 km as of July 2014
                              mods: air filter box 'tuba', headlight relay harness, J-mod (around 186,350 km), 70mm throttle body, KYB Gas-A-Just shocks, aluminum driveshaft, ARA3 PCM

                              Comment

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