Trans Tune for hard downshift [SOLVED]

I have 2005 Lexus ls430. When stopping, it downshifts hard at about 4 mph. The fluid is dark. Will Sea Foam help?

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Jim D.
1 year ago

Thanks for the question, Ty. Can’t say for sure, but Trans Tune might help.

Fluid condition plays a strong role in shift condition and timing. Best bet is to try Sea Foam Trans Tune as a pre flush for 50-100 miles and see if shift condition improves.

If the shifting improves with Trans Tune, flush transmission, and then use Trans Tune as a fluid conditioner.

However, there are a few repairs that I see that are pointing to PCM replacement due to a shorted shift solenoid driver. If condition isn’t improved with Trans Tune, the vehicle should be diagnosed by a professional technician.