Fluid and Filter changes

[Instrument 40]

2000 5.3 Silverado, 126K, no problems other than sending unit.

Would like to change the transmsion filter and fluid, never been done, 126K miles. I know, should have been done sooner. Having no problems with trans but wondering if I were to change what are the chances that I may cause problems?

Also, want to change the coolant as well, along with hoses and thermostat. Not running hot just needed PM. What coolant should I use? I was told that I would need to buy the housing along with the thermostat, is that correct? Can I just drain the system and then add the coolant mixture back in or Am I trying to oversimplify a job that more complicated than what I have spelled out?

[GM-Tech]

I don't see where it would hurt to change the tranny fluid/filter at this point in time. Yes, the thermostat is part of the housing.

 

The coolant is Dex-Cool. Use it. If you just drain the radiator and replace, you're only getting about half the old coolant out of the system. I personally would have a flush done that replaces all the coolant.