Has anyone else experience this.

My truck is a 2017 2500 CCSB.

I deleted it at 34000 miles and since then have been dealing with low line pressure in 4th gear.

I have 46000 miles now and the pressure starts out great in the 150 to 160s.

Then once my rpms hit about 2200. It drops to 130 even at at wot.

I have changed both filters and all fluid.

The local shop says I need a shift kit and new pressure pump, but if I can get 160 to 170 in 5th I doubt my pump is bad.

I dont race my truck only tow with it.

More about my truck tow tune with trans tuning from breakout diesel in Idaho. Banks air horn flo pro exhaust.

Before the delete I never threw a code and since I bought the truck new I have monitored every thing with a Edge Insight.