2001 GS300. No codes, no CEL, seems to shift fine in manual mode but really revs out between 2-3 I believe. When driving conservatively in D it seems ok but when you get on it it’s very noticeable. My son (his car) said the other day going up a hill it was not wanting to downshift. Trans was making a rattle sound the other day, one quart low. Added fluid and sound went away. Fluid already in there looked fine (still red, not burnt). Does this sound like a solenoid to you or something more serious?

 

A solenoid issue is sure to throw a code. You may want to have it scanned by a shop with a scanner that can read the transmission specifically. Not all codes set the CEL. If no codes are present, it is not likely a solenoid issue. When you say "really revs out" do you mean slippage/high rpms? Or it just wont shift and continues to try and pull before without upshifting? You may need to look as the throttle/APP as these have a lot to do with shifting.

 

Yes, slippage /high rpm’s. Darn, I was really hoping for a simple solenoid but it sounds like that won’t be the case. Already making plans to have it diagnosed. Thanks.

 

Unfortunately slipping isn't a solenoid issue, it's worn clutches that can't hold anymore. Time for a rebuild or replacement.

 

So it turns out the erratic behavior of the trans was a side effect of an exhaust that was super restricted thanks to a cat that had self destructed. Still not a cheap fix but a lot easier!