Shifting to 3 is not ever a problem, and is a good idea in your hills if the road is wet. What I object to is the TCU down shifting to 1st at 25mph or less instead of keeping it in 2nd. A real pain in the Rockies when you want to do 20-25mph on a really steep mountain pass.

Some of the DTCs are minor and after getting set, never clear themselves. I try to clear all codes, except B2, at every oil change.

You might contemplate flushing the tranny fluid if it hasn't been done. Do NOT use a comercial machine to do this, but use the IPD method of unplugging the top tranny cooler hose and flushing 2 quarts at a time until the fluid is pink.

Keep having fun,

Klaus
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The 164 has a new home, all I am left with are a 95 854T and a 98 V70R :)