So recently we were on the top of mount Washington in NH. This is my wife's car and she has 2017 RDX with tech/advance (all the bells-whistle model) package. While going up, I was able to keep the gear in D2/D3/D4 and I did not notice any issue. But while coming down, I wanted to keep the car in the lowest possible gear to use engine braking. I wanted to keep the car in D1 (or M1 in S mode). I tried to downshift using paddle but D1 just blinked and then car went into D2 (or M2 in S mode). Under S mode I wasn't able to keep the car in M1. I had to constantly use the brakes under D2/M2. While talking with local Acura dealer, they said you cannot use D1/M1. I'm puzzled. I looked at the manual. I called acura and they said Is should be able use M1 under sports mode. It should not shift to M2. Has anyone else experienced this issue?

While reading the manual, I did notice second gear lock. I tried to unlock it but it did not work.

Second gear lock mode
If you pull the (+paddle shifter while stopped or driving at 6 mph (10 km/h) or less, the gear position will be locked in 2nd gear. This makes it easier to pull away on slippery surfaces such as snow covered roads.
To cancel the 2nd gear lock mode, pull the (- paddle shifter, or move the shift lever from (S to (D

This is very annoying. Why can't car be in M1 when driving downhill?

 

Correct. You CANNOT hold 1st gear under any mode in the 2nd gen RDX. Just the way it is. Funny thing is, I had a 1st gen RDX and you COULD hold 1st gear. I think for safety issues or not accidentally blowing up the engine they removed that option on the 2nd gen.

 

Yes, the transmission behavior contradicts what it says in the manual. I was just up Mt. Washington myself a few weeks ago, and decided to take the shuttle van instead of driving my 15 RDX because it does not stay in 1st gear no matter what. You can get it to 1st if you're at a stand still or really crawling at 5 MPH or less, but it will automatically up-shift to 2nd almost immediately no matter what mode it's in.

 

Thank you. This is super annoying. Why even then give D1 if the customer won't be able to use it.