Hello, 

I have a 2012 Ford F150 with the 5.0liter v8 - 6 speed transmission and 160k miles.. About 6 months ago I noticed a small rattling noise after accelerating from a stop while in 1st gear. Otherwise no real shifting issues. Took to a transmission shop and said it was the front head of the transmission, but I could still get another 50k miles from it or more. They didn't charge me anything and did no repairs.

Last week I hit 160k miles and was doing my routine oil change every 5k miles. Went to valvoline and they talked me into a transmission fluid replacement and flush. I don't know if the car had ever had the transmission fluid replaced. I bought it at 100k miles. The rattling noise is still there and is not any worse, but I feel that the 1st gear shifts into second much quicker. While in second gear trying to get to third gear, whenever I hit 2000rpms it seems the rpms suddenly drop to 1800rpms and then continue to climb their way back up to 2200rpms or so to shift to 3rd gear. I also feel some slight tremors, it seems, or more noticeable vibrations, while cruising on 6th gear on the interstate around 1800rpms.

I looked this up on the internet and came across your videos about not recommending flushing transmissions especially at this milage. Now I am worried I have made things worse, as it seems I have, and feel that I decreased my transmission's remaining lifespan. The gear shifts do not seem to be rough. 

Is there anything to be done in this situation or will it eventually just need the transmission replaced? Any recommendations for shops around the Nashville area? I live in Murfreesboro, TN. Thank you so much for your help and advice.