Looking at a SRT-6 that has over 50k miles. Oil changes done, fuel pump replaced, newer tires put on. But...it has the original coolant in it transmission fluid and diff fluid. Is that a big red flag not to get? Since those fluids are over 20 years old?

 

No, with that low mileage. If you buy it, you may want to change the fluids?

 

I have changed the coolant 2x but never the tranny or diffy. Maybe when I get closer to 60k - there is only 44k on it.

 

I don't have an automatic so I don't know about changing that fluid. The diff and coolant are easy to do.
Here's a link to a post I did when I changed my differential oil: LINK Differential oil change

 

My main concern if the damage has already been done. It's very rare for a used vehicle to be maintained properly. People seem to always skip out on all the other fluids except for oil. 😔.

 

Age matters just as much. It's not all just about the mileage.