Im currently in Colorado for a summer vacation, and I drove my 05 TL with 108k on it almost 1000 miles to get here. Ive also been averaging about 120 miles per day sightseeing. Everything was fine on the way, but the first day we spent here we went driving up a long, steep mountain road and startin at about 40 mph it seemed to not want to shift. The rpms sat between 3-4 until it finally would catch gear and drop to 2. I thought this was just due to conditions, but since then it seems that if I dont have momentum in my favor, or if I accelerate at highway speeds after cruising steady for a while, the rpms rise and hang between 3-4 for an extended period of time before dropping. Now when this happens, the car does continue to accelerate, but at a sluggish rate until it shifts. This is anywhere between 40-70 mph. At city speeds, everything is fine although the 1-2 and 2-3 shifts have always been slightly jerky I did do a 3x3 drain and fill a couple months ago and I know im going to catch hell for this but no I did not use OEM fluid I used Valvoline. I checked fluid level and its full and fluid looks clean and smells fine. Is this a problem or i it to be expected given circumstances? Thanks for any input

 

It takes more effort to go up hill so the engine will need to work harder to get you up there. That's why the car shifts at a higher point. Its perfectly normal.

 

Good to hear...Im not sure if I explained it well enough but what do you make of this: here and there while cruising on the highway, if I lose momentum after peaking a hill or even on a slight incline, the rpms peak arpund 3 1/2 and it wont accelerate smoothly. Instead, even under light throttle, it bogs down, then zooms off as if I just floored it. This only happens spontaneously so Im not panicking but I had never noticed this behavior before

 

Maybe Im being an idiot...it makes sense I would have to give it more gas uphill but it just seems more sluggish than usual.