1994 ls400 shifting weird
#1
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1994 ls400 shifting weird
Hey all,
1994 ls transmission has been shifting weird. To start. last week it was shifting great accelerating, but would struggle downshifting on its own(like slowing down a standard transmission without pushing clutch in) Now, it is having that issue, as well as shifting from first to 3rd like instantly then also od quickly after that. Now, I have been fooling around with the shifter and if I shift it manually it shifts smooth accelerating and decelerating. Also, if I let it shift automatically from the 2nd gear location it will shift correctly from first to second, then I will have to shift to D for it to continue as would be expected. The filter and fluid were changed 2 months ago as routine maintenance, I used the recommended fluid for that, as well
The car has nearly 240k on it. and has been flawless
I did some research about this issue and cannot really find exactly what I'm experiencing .Most posts about this lean towards #2 solenoid. I did the engine/transmission diagnostic as instructed here on the forum. There are no codes. Also, the fluid levels are where they should be and a nice pink color.
I'm guessing the problem is the solenoid, but not the electrical part of it that would throw a code? I think it must be sticking, as none of these symptoms happen all the time downshifting or accelerating. Does this sound right?
Thanks for your input
Skip
1994 ls transmission has been shifting weird. To start. last week it was shifting great accelerating, but would struggle downshifting on its own(like slowing down a standard transmission without pushing clutch in) Now, it is having that issue, as well as shifting from first to 3rd like instantly then also od quickly after that. Now, I have been fooling around with the shifter and if I shift it manually it shifts smooth accelerating and decelerating. Also, if I let it shift automatically from the 2nd gear location it will shift correctly from first to second, then I will have to shift to D for it to continue as would be expected. The filter and fluid were changed 2 months ago as routine maintenance, I used the recommended fluid for that, as well
The car has nearly 240k on it. and has been flawless
I did some research about this issue and cannot really find exactly what I'm experiencing .Most posts about this lean towards #2 solenoid. I did the engine/transmission diagnostic as instructed here on the forum. There are no codes. Also, the fluid levels are where they should be and a nice pink color.
I'm guessing the problem is the solenoid, but not the electrical part of it that would throw a code? I think it must be sticking, as none of these symptoms happen all the time downshifting or accelerating. Does this sound right?
Thanks for your input
Skip
#2
Lexus Champion
by far the most common cause of shifting issues on a '94 with no codes is failing ECU capacitors
this makes perfect logical sense if you think about it, for three reasons:
● the LS400 does not have a seperate computer to control shifting, all shift decisions are made by the ECU
● the 94 LS400 (and several other years) have a known factory defect in the ECU capacitors
● Florida is by far the most common state for this issue to show up in, must be exacerbated by heat/humidity combination it seems
this makes perfect logical sense if you think about it, for three reasons:
● the LS400 does not have a seperate computer to control shifting, all shift decisions are made by the ECU
● the 94 LS400 (and several other years) have a known factory defect in the ECU capacitors
● Florida is by far the most common state for this issue to show up in, must be exacerbated by heat/humidity combination it seems
#3
BahHumBug
iTrader: (10)
by far the most common cause of shifting issues on a '94 with no codes is failing ECU capacitors
this makes perfect logical sense if you think about it, for three reasons:
● the LS400 does not have a seperate computer to control shifting, all shift decisions are made by the ECU
● the 94 LS400 (and several other years) have a known factory defect in the ECU capacitors
● Florida is by far the most common state for this issue to show up in, must be exacerbated by heat/humidity combination it seems
this makes perfect logical sense if you think about it, for three reasons:
● the LS400 does not have a seperate computer to control shifting, all shift decisions are made by the ECU
● the 94 LS400 (and several other years) have a known factory defect in the ECU capacitors
● Florida is by far the most common state for this issue to show up in, must be exacerbated by heat/humidity combination it seems
The Aisin transmissions in our cars reqire reasonably clean Toyota T-IV fluid. Swap all the fluid out (fluid exchange, not power-flush) for fresh fluid and then see if you still have an issue, usually that resolves most minor issues.
#4
Lexus Champion
Actually the single most common issue for shifting issue on the LS is simply old/incorrect fluid type. Hundreds of threads throughout the forum (SC, GS, LS, and IS subforums) support this.
The Aisin transmissions in our cars reqire reasonably clean Toyota T-IV fluid. Swap all the fluid out (fluid exchange, not power-flush) for fresh fluid and then see if you still have an issue, usually that resolves most minor issues.
The Aisin transmissions in our cars reqire reasonably clean Toyota T-IV fluid. Swap all the fluid out (fluid exchange, not power-flush) for fresh fluid and then see if you still have an issue, usually that resolves most minor issues.
as with any transmission issue on any car though, the first step is always fluid and filter change with the correct manufacturer specified fluid. - if the car has gone an excessive number of years or miles (like greater than 7-8 years or more than 100K since a fluid change), then the new fluid should be introduced a quart at a time, over the course of a year, so as not to "shock" the transmission into a premature failure. - this is why it is all to common to hear of someone who had the fluid completely changed and then a transmission failure happens soon afterwards!
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as with any transmission issue on any car though, the first step is always fluid and filter change with the correct manufacturer specified fluid. - if the car has gone an excessive number of years or miles (like greater than 7-8 years or more than 100K since a fluid change), then the new fluid should be introduced a quart at a time, over the course of a year, so as not to "shock" the transmission into a premature failure. - this is why it is all to common to hear of someone who had the fluid completely changed and then a transmission failure happens soon afterwards!
#6
Lexus Champion
crack the drain plug, catch a quart, tighten her up good, add a quart of fresh T-IV
repeat this in a couple months
double check that you do not leave a leak at the drain plug, keep checking fluid level with car in Park, transmission hot, on a very level surface, I would check it daily.
repeat this in a couple months
double check that you do not leave a leak at the drain plug, keep checking fluid level with car in Park, transmission hot, on a very level surface, I would check it daily.
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#9
Lexus Champion
this one from Mityvac
and this style
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