LS 400 Transmission down shifting rough
10-27-13, 03:46 PM
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LS 400 Transmission down shifting rough
My LS 400 feels like you're hitting a rumble strip when it down shifts going up a grade. It only does it when losing speed and downshifts, when the torque converter unlocks. If I'm not mistaken, they shift from 1st to 2nd to 3rd to overdrive to torque converter lock. It's when going up a grade and barely losing speed, I feel a rumble and the rpms go up but if I push the overdrive button it shifts again. So it's seams like when the torque converter unlocks... Anyone had this happen?
10-27-13, 04:18 PM
#2
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change the fluid and filter, making sure to use the genuine Toyota filter and genuine Toyota T-IV transmission fluid only
If you still have the issue, it is likely to be failing ECU capacitors - the ECU controls the shifting on the LS400 and this is a common issue on '93's as the capacitors in the ECU have a known defect!
If you still have the issue, it is likely to be failing ECU capacitors - the ECU controls the shifting on the LS400 and this is a common issue on '93's as the capacitors in the ECU have a known defect!
10-28-13, 06:41 AM
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This this shifts beautifully. It only vibrates when downshifting going up a slight grade in the highest gear. All other shifting is perfect. I am looking for someone who has had the same thing happen. Seems like a lockup malfunction and or a shudder...
Last edited by Dwaino; 10-28-13 at 06:53 AM.
10-29-13, 03:36 PM
#6
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I agree that the transmission mount would be the likely cause of the vibration, but it also sounds like you have a gear selection type of issue as well
The transmission mount is low cost for the genuine Toyota part (you don't want aftermarket) and very easy to install
at least the vibration portion would likely be solved, then you could address why it is getting confused at to what gear it wants to be in, which is why I mentioned the ECU
The transmission mount is low cost for the genuine Toyota part (you don't want aftermarket) and very easy to install
at least the vibration portion would likely be solved, then you could address why it is getting confused at to what gear it wants to be in, which is why I mentioned the ECU
Last edited by LScowboyLS; 10-29-13 at 03:40 PM.
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