Skipping gears on purpose 6L90

[truethinker]

Hello all. It's been a while.

Working on a 2015 GMC Sierra 2500HD, 6.0L, 6L90E, SRW

My Duramax is down with a burnt up DEF heater. So, while awaiting delete parts and tunes I jumped in the work truck and after a few days of regular driving it started dropping 3rd, 5th and reverse. I know it's probably a cracked 3,5,R drum. The problem is, this truck needs to keep getting me from point A to point B until the work on my DD is done. Probably a couple of weeks.

I disabled everything above 2nd gear, in tow haul, in order to plow snow. That worked well. For standard driving I'm running the RPM's to 4k in manual 2nd and then clicking up to manual 4th while off the throttle. Once I see the revs drop twice I get back in the throttle and drive in 4th. I can't get to 6th. Also, I find that reverse works better in Tow/Haul.

I need some help as soon as anyone has time. I need 3rd gear and 5th gear totally deleted. Also, I can't seem to figure out why reverse works better in tow/haul.

Perfect scenario would be;
-NORMAL MODE
--skip 3rd and 5th
--make reverse act like it does in tow/haul
--make these changes also work in cruise

-TOW/HAUL
--disable everything above 2nd gear

This tune file already has the Tow/Haul lockout above 2nd and it's working well for snow plowing.

Any help would be greatly appreciated.