I am about to do an ATF flush on my truck and I was confused on one part of the procedure. I have read on here that you can simply drain the oil and put the ATF in without changing the oil filter (using the one currently in the truck for the cleaning). However, I have also read that you should use a new filter just for the procedure itself (thereby needing two new filters at the time of the flush). Which one of these is true?

Also I just wanted to confirm that you have to do a regular oil change roughly 1000 miles after the flush.

Finally, I want to know if it is actually safe to do on my truck with 126,000 if I'm not going to be able to clean anything else (remove the oil pan etc.). I don't have the tools or the room (I live in the city) to do anything like that so I don't want to attempt a procedure that might clog up my engine if I don't clean it out. So, this being the case, should I just leave it alone? Any thoughts? Thanks a lot for the help.

 

First, I have not seen, but maybe 2 people that had to pull their pans after cleaning their engine, and both of these were abused engine with ton of built up crap inside.
I usually recommend using the old filter when doing the flush, may be some benefit to using a new one although we never did when we did this in the shop.
Yes, you need to check your oil color around 1000 to 1500 miles cause it can continue to break down sludge for awhile afterwards thus causing you to do an early oil change.
Once this has been done I would recommend on every other oil chamge that you buy a 1 quart can of Gunk engine flush and use it before your oil change to maintain a cleaner engine and better oil flow/pressure.