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Slow Roll Transmission Problem

Discussion in '80-Series Tech' started by tomlite, Mar 16, 2004.

  1. tomlite

    tomlite

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    More so in Power than economy mode. When I slow down to about 10 mph then Gently Press the gas pedal, it feels as if the engine revs up for about 1/2 second before the transmission catches it. Then everything else feels normal.

    1997 Lexus LX450 with 78,000 miles. When I first bought the truck about 6 months ago, the transmission fluid looked cloudy with virtually no smell. I kept domping the contents of the pan and refilling with about 4 quarts. I know it is supposed to take less, but that's what drains out. After about 6 dump and refills the transmission fluid is correct level, very little discoloration, no burnt smell. I don't that the filter has ever been changed.

    It looks as if someone has been adjusting the Throttle Position Sensor. Do these get set to a specific number or do they get adjusted until the Idle Contact closes.

    Thanks in Advance,

    Tom
     
  2. Rookie2

    Rookie2

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    hmm.. strange, a guy meeting your description was having this same problem, but I think he said his cleared up after a couple of dumps. Anyways, I'd be interested to know the answer to this problem, since I too experience a little "spooling" at low speeds.

    later (tem??),
    Rookie2
     
  3. MoJ

    MoJ Moderator

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    Had the same problem in my 91 FJ80 and have it to a much lesser degree in my 94 FZJ80. Would love to hear a solution. I've developed a feel for when it will do it and try to avoid making it happen.
    -Jason
     
  4. floatinghat

    floatinghat

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    Could it be the lock up rpm on the Torque converter? mulling around at 10mph hmm, I idle around 25mph in drive on a flat road. Hmm, wonder what my MPG's are at idle in drive? oh well I'm over that now.
     
  5. Outback

    Outback

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    I asked this same question to the Aussie experts...

    Dear Jody

    In response to your question :

    G'day Orto,

    I'm in the US and have a 1993 FZJ80 Land Cruiser. When coming to a stop sign and not quite stopping fully, the transmission is slow to shift down to 1st, and when accelerating from that slow roll it kicks down into first pretty hard. What
    causes this slow downshifting? I have 265,000 miles on her now. All other
    shifting is normal and smooth. I have had a shop look at it and they say it is
    all "in spec" and adjusted properly. They say it's acting like a loose tranny
    with 265,000 miles on it. I don't buy that. What do you think? Also, would it
    be worth it to ship an extreme A442F to the US?? I'm in no hurry, so it can go
    by boat. Thank you for your time, I look forward to your reply.

    My answer is : I would think that it is completely normal because of the fact
    that the computer controls the gear changes and not the transmission. It is
    normal for the A442 to down shift quite late and leave the car struggling to pick
    up the pace again until you kick them and I can tell you that because I have the
    same landcruiser and it does the same thing, Not all the time but most, it very
    much depends on the road speed and there is a fine line between when it feels it
    is time to down change. We do send transmissions to the U.S on a regular basis
    and it is quite cost affective to do so. You might not need to go as far as the
    Extreme because we can do standard rebuilds and fit our Extreme Recalibrated
    Valve body as we go. This can also be fitted during a rebuild if done in the
    U.S. But it still wont fix the down speed shift timing. Let me know.

    Regards,

    Rodney

    Thankyou for visiting the Wholesale Automatics web site, and I hope I have been
    able to help you.

    Orto
     
  6. colo_tlc

    colo_tlc

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    Same problem here, patient is a 1997 80 w/ 101K. Is this normal? How can I find out if there is a problem I am gettin gready for road trip and would like the problem or lack there of identified soon. All help is greatly appreciated. :beer:
     
  7. alaskacruiser

    alaskacruiser

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    This problem is not limited to the A442F. I have had the same problem on my '97 LX450 with the A343F since I got it at 35k miles. Also had the same problem on my old '93 Landcruiser with the 442. So I'm pretty sure this is normal.
     
  8. Scamper

    Scamper

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    I've noticed this since new...pretty sure it's norbal, or I've missed an opportunity for an under-warranty repair :doh:

    Tom
     
  9. Extreme_Trans

    Extreme_Trans

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    Hi it's Rodney here from Wholesale Automatics. I see this all the time and they all do it. As for the reason, well I have some fact and some thought. The first thing is that the A442F and A343F can hold 3rd gear at an incredibly low road speed with barely any throttle pressure, this is normal but when you ad some more pressure you think that the transmission will down change smoothly and take off and this in fact happens. But now add even more pressure 1/2 throttle and more and now we have a problem as the ECU can command the transmission to change gears faster than the transmissions hydraulics can keep up. because on a 1/2 throttle acceleration the transmission is now being told to down change 2 gears at once and is releasing the 3rd gear almost instantly and the engine revs start to quickly pick up before the hydraulics get the transmission into 1st gear. In other words the transmission as gone "s***" I wasn't ready for that but in mechanical terms we have just experienced a miss-timing in gear shifts. While Toyota does quite well with it's ECU designs and programming it is imposable to account for every situation. Infact The A442F has 2 trait hic-ups that are well known. One is the above and the other is the harsh thump when backing off the throttle just as the transmission is about to change gear ( I hate that one! ) but they all do it to some degree. My valve bodies will NOT fix either. It's Just what happens when you have a computer controlling shift points and a transmission controlling the pressure. Still a great transmission and a near perfect ECU. On the A750E 5 Speed the Computer controls both. I can mention dozens of cars that have ECU's that should be Shot! I hope this helps. Regards Rodney
     
  10. Outback

    Outback

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    Rodney,

    Thank you so very much for posting your expertise on the Land Cruiser automatic transmissions. I read your post almost mezmerized by the vast knowledge that professionals like yourself bring to this forum. We should all realize how lucky we are to have these folks amongst us.

    Thanks again Rodney... Please stick around.

    Jody.
     
  11. turbocruiser

    turbocruiser SILVER Star

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    Rodney, I echo Outback, thank you for the explanation, it was perfectly understandable and totally took the worry of this thing out of my mind. Also, exceptionally honorable and honest of you to go out of your way to explain that your valve bodies would not address this particular shift pattern although they do address so many other things!!! Cool man, thanks.
     
  12. 92Cruiser

    92Cruiser

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    Rodney,

    I would like to thank you also for your info. That second problem regarding the back off throttle thump has bothered me for the past 2 years. I kept thinking my tranny was on the way out but now I won't worry about it. The u-joints have to take a beating though.


    Brian