Need help trobleshooting tranny...

[cliffj59]

I was coming out of Knoxville Tenn. a while back rolling down I 40 looked down and the trans temp was up about 245. Normally runs about 180 to 200. I was pulling a 10,000k horse trailer thats all I do with this truck. Pulled over to the side and waited for it to cool down, got back on the Interstate and watched the gauge for the next 3 hours never got back up that high again. Fluid smells fine not burnt loks nice and red. Every since then it feels like the trans is slipping. I have 120,000 miles on it the last time I changed the fulid and filter was about 20,000 miles ago also added a BTS valve body. I do have a chip DP Tuner F5 with no start 40 tow 60 tow 80 tow and 80 econo. I was rinning in 60 tow when it went hot. I have never abused this trans, no WOT, no burn outs, nice smooth starts and no OD under 55. Now I have done alot of searching here to maybe see what the problem could be and have came up with these options:
1. TC going out
2. Clutch packs slipping.
3. Sprag gear ?
4. Bypass line maybe stopped up
5. Just time for the OEM tranny to let go
6. Inline filter maybe stopped up.

I will be taking it to the trans shop to see if there are any codes in it. This is not my daily driver so I havent been in a real big hurry to check it out.

Thanks for any input here

2000 F250 4x4 EC, Zood Dad mod, BTS VB, Isspro gauges, Afe stage 2, 4" Mbrp turbo back, DP Tuner F5