Issues immediately after startup on 1999 infiniti g20 (automatic transmission)

My problem exhibits itself in two symptoms that persist until the thermostat needle rises to normal temperature. In order to avoid these issues, I purchased a remote starter so that I can let the car warm up in the morning before I get in and drive. The first symptom is a loss of acceleration power in second gear that is accompanied by a hollow crunching sound. Even if I slam on the gas, the car will accelerate at an elderly pace until the rpms pick up a bit. The second sympton arises when I have to brake. If I’m in second gear or above, pressing the brake pedal causes the same holllow crunching sound, but the sound is more intense and if I deccelerate too quickly, the car stalls. On bad days (like everyday I drive this car isn’t) my car will also stall, after exhibiting one or both of the previous symptons, when I have to put it in drive. I have found that I can avoid stalling by shifting the car into nuetral as I brake. This issue has been accompanied by two rare symptons: teetering reverse (during warm-up period) and a check engine light code indicating “2nd gear ratio incorrect.” I should note that when the car is warm, the car’s shifts are not always smooth.

I don’t know if this is related, but recently I’ve noticed that once my car is warm, if I have to apply more pressure than normal to the brake, I hear crunching (different from the hollow crunching noted before) and liquid splashing.