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Toyota Tacoma Transmission Problems



  • Greetings, was wondering if anyone has any thoughts on why my 99 Tacoma's automatic tranny suddenly started redlining be fore finally shifting up (HARD). Fluid is fresh and clean and no lights have lit on the dash... 160k miles and have never had ANY tranny issues before (believe it or not). Hoping for some insight, thanks in advance.

  • befuddled2befuddled2 Posts: 111
    Man, I wish I could explain it. The more stories I read and hear about autos anymore the more convinced I become that electronics on automobiles is not necessarily a good idea. The reliability factor of computers and sensors is not there and therefore dangerous. I wish you well.
  • Not sure if this will help on your Taco, but it's almost a sure-fire fix on older domestic transmissions. The symptoms indicate either a vacuum leak between the intake manifold and the transmission's shift modulator valve or a faulty shift modulator valve in the transmission (diaphragm or o-ring, possibly). Check for vacuum leaks first at the manifold and transmission then along the vacuum hose between the two. Usually, just replacing the old vacuum line will do the trick.

    Hope this helps,

    That Other Guy
  • wwestwwest Posts: 10,706
    edited June 2010
    Sorry, SOP, YOU'RE the one at fault.

    These days with fuel prices as high as they are, and along with the emissions issue, it would be UTTERLY STUPID for an automotive engine and transmission, drive train, manufacturer to continue to maintain ATF line pressure at a high level when the transmission is placed in neutral or park. Shift the tranny into a drive position with the engine idling and of course it might take 1-2 seconds to build, re-build, enough ATF line pressure to satisfy the valve body operational requirements and then enough additional pressure to actually engage, fully and firmly engage, the necessary drum clutches, 1st gear, HIGH torque, drum clutches.

    And all the while, of course, the engine remains at idle regardless of gas pedal position.

    Either buy a stick shift, stop complaining, or learn to live with the issue. Your vehicle was not designed to be shifted into neutral in those circumstances. The new torque converters equipped with lockup clutches have such weak torque coupling charactoristics with the engine at idle that the FE gain using your shifting procedure is probably negligible.
  • wwestwwest Posts: 10,706
    "..What's wrong with a throttle cable.."

    Ask that of an owner of a 99 or '00 RX300 that has had the transaxle replaced prior to 80,000 miles, maybe even 2 or 3 times and the latter ones often at least partially, if not altogether, on the owners nickel.

    With the abolition of the old style ATF pump, pressure relief spring valve and pressure holding accumulator in these new transmissions to improve FE the engine MUST be held at bay, IGNORING the gas pedal position until such time as a newly selected gear ratio's drum clutches can be fully and firmly engaged.

    The early RX300's did not have DBW so the engine RPM would rise in direct response to gas pedal position, all the while the drum clutches were in the process of being "meshed".

    By '01 Toyota had somewhat alleviated the problem by reprogramming the engine/transaxle ECU firmware in order to sustain the ATF line pressure at a somewhat higher average level. The transaxle premature failure numbers declined accordingly.

    What we got, owners of '01 to '03, was ATF that was so overheated that the recommended maintainance schedule for an ATF drain/flush/refill went from infinity (life of the vehicle) to ~15,000 miles or signs of ATF degradation, whichever cam first.

    The RX330 came with DBW and its own set of problems as a result. 1-2 second re-acceleration delay/hesitation soon became the NORM throughout the Toyota/Lexus/Scion fleet.
  • wwestwwest Posts: 10,706
    edited June 2010
    "..there is definitely a fix..."

    No, there is only a PARTIAL fix. Only some instances of the 1-2 second re-acceleration downshift delay might be eliminated, mostly those wherein the driver "knows' the future, immediate future.

    See post # 510 for a definitive explanation.
  • wwestwwest Posts: 10,706
    What you are most likely experiencing is the "new" coastdown engine "fuel-cut" procedure/technique now in more widespread use to improve FE. Basically the engine will be COMPLETELY starved of fuel during coastdown as long as the transmission can be downshifted enough to keep the engine from stalling. Obviously this technique must be discontinued before, substantially before, you come to a full stop. The "lurch" forward, feeling of being bumped from behind, is the result of the "upshift/surge" once the technique is discontinued. The downshift into first gear will then not occur until you have come to a full and complete stop.

    In my '01 RX300 the transmission makes a final UPSHIFT (lockup clutch release..??) as the road speed declines to about 10 MPH.
  • befuddled2befuddled2 Posts: 111
    I'm not a mechanic and obviously not aware of all these computer driven techniques of operating a automobile (perhaps the wrong term anymore). With all the problems I and others have experienced one has to ask is this technology really buying us anything? Like all things computer driven they are not reliable and very expensive. The reason for all this??? Better gas mileage? Are we really getting it?
  • ianc435ianc435 Posts: 10
    edited June 2010
    SOP ?????

    Find one other vehicle on the planet that exhibits this same condition. One of them was an 07 sienna. Yeah and that conditon was fixed (right out of the toyota techs mouth.
    You don't sound (read) like a nice person???.
  • wwestwwest Posts: 10,706
    edited June 2010
    The factory shop/repair manuals at indicate that a shift from neutral to reverse or drive will take 1-2 seconds. Toyota began using real time control of ATF line pressure back in about '98. With this capability why would the manufacturer not improve FE and reduce ATF heating by dropping the ATF line pressure to zero with the shifter in park or neutral..??
  • wwestwwest Posts: 10,706
    edited June 2010
    The TSB "fix" for the Sienna involves a 1-2 second re-acceleration downshift delay/hesitation, not the now "standard" delay shifting into drive.

    See posts # 510 and 551.
  • ianc435ianc435 Posts: 10
    So let me get this cleared up.

    When I shift my truck to drive and the vehicle starts moving forward (in gear) The pedal partialy responds and then when line pressures are satified the computer will reference pedal postion no matter where it is. and apply engine response thus leading to an unitended and undesired accelaration to anyone that it not aware of the problem. That (my opinion) is dangerous. I nearly drove up the backside of a car the first week I had the truck. What puzzles me is the 09 08, 07 do not exhibit this "characteristic". This could be easily overcome by anticipating transmission function by ways of the brake pedal.

    I also came across a thread about undersized torque converters for thes trucks??? any thoughts.

  • This is what my truck is doing... when you come to a stop and remove your foot off the brake to continue, it lurches forward, all the other shifting is fine. My truck only has 67K miles.

    The reason I'm here and asking, is that I've taken it to three different mechanics with 3 different answers...see below.

    I was told I have 1) bad motor mounts
    2) I needed a 4WD service... even though it's a 2WD?
    3) that my fluids may be low, which I checked, all are within range

    Has any one else had this issue or suggestions?
  • befuddled2befuddled2 Posts: 111
    You say you checked all your fluids. How did you check your transmission level?
  • mtrialsmmtrialsm Posts: 159
    My '09 Tacoma radio is having problems also. This is intermittent: Start up my truck, the radio comes and and ejects all the CDs, no display or a bunch of odd displays. After a few minutes of pushing on/off button, the radio works fine for a few days. this has happened three times now. the next time it happens I'll stop by dealer to see what they say. My truck has 30k miles on it now, I hope to keep it for 8 years, so glad I purchased extended war. No trans. problems yet, still getting 20-22 mpg. dbl-cab, 2x4. w/TSB shock upgrade.
  • wwestwwest Posts: 10,706
    Hill Assist..?

    Easy to inadvertently "arm".

    The way I read it if you press slightly harder on the brake pedal AFTER coming to a full stop the Hill-Assist is armed. Arming the Hill Assist results in all four brakes being lightly applied in order to prevent the vehicle from rolling on an incline. Once you subsequently apply, re-apply, pressure to the gas pedal the brakes are released and shortly thereafter the engine will respond to the gas pedal.
  • ianc435ianc435 Posts: 10
    happens when i shift from park or neutral to drive.
  • mtrialsmmtrialsm Posts: 159
    My radio had faulty display this morning, (4th time in several months), but other wise working OK. I didn't touch it and drove straight to dealer. Showed them the display, the rep. said he would order a new radio. I turned the truck off and radio went back to normal. Glad I didn't touch a button,,,,,,
  • mtrialsmmtrialsm Posts: 159
    Got new radio installed and front floor mats today. Took 50 minutes. They said it would take 45 minutes, I'll give them the slack:)
  • gypratgyprat Posts: 3
    edited July 2010
    Bought a new 2010 Tacoma, manual transmission, 4 cyl.
    Transmission is very hard to shift. 1st gear can only be engaged if truck comes to complete stop. It takes a lot of pressure to get it into first, it almost feels like breaking a chicken bone. I do press clutch all the way in and had driven many cars with manual trannys with no issues. It's hard to drive this truck in a stop and go trafic where the speeds are too slow to engage the 2nd gear and the 1st gear can not be engaged. I have to shift into second and burn the clutch to accelerate the truck to above 15 MPH.
    Shift pattern from first to second is very notchy, sometimes with a loud clunk. 2nd to 3rd is better but sometime I hear a clunk too.
    Reverse is another problem. Shifting into reverse is very hard. One morning I could not get it into reverse at all. I had to move the truck forward slightly and then use a lot of force to shift into reverse. I wonder if braking the shift lever is covered under Toyota warranty?
    Does anyone have similar problems? The dealer said everything is normal (like everything else with Toyota vehicles warranty claims. It sure seems like it).

    I'm very dissappointed with the quality. Especially with the fact that rear differential had hardly any oil in it since new. I described this problem in a defferent post under the OIL thread.
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