Straight forward I have a couple questions answer if possible thanks guys

1. I’m about to replace the passenger Cv axle I’ve never done a transmission flush will doing so now
After 204,000 miles be bad is it ok to replace oil ?

2. What could trigger the car to have a shaky idle randomly
When I stop at a light it only happens sometimes steady rpm and out of no where it drops like it wants to shut off

3 is it normal ? I took out my spark plugs to see overall health and they are white/ grayish tip
With tip still being like new changed 10k miles ago

Thanks for the help

You'll need to drain the trans to replace the axle anyway. Otherwise, once you pop the axle out, all the oil will come out with it.

When was the last tune up? Cap, Rotor, Wires? If you replaced the plugs 10k ago, grey coloration is normal.

You almost never want to "flush" your trans at a shop, especially with high mileage. You'll want to just drain in your garage and refill. Do that for the next few engine oil change intervals and you'll be good for a while (probably the life of the car/trans/engine) IMO.