Auto trans Stopped in D on incline pops then grinds as it drifts rearward

Brand new Off Road Double cab and I noticed with the transmission in drive on an incline the truck drifts back with a pop then a grinding sound. Never had an auto transmission act that way. The anti-skid light illuminates on the dashboard. Already contacted the dealer. Seems to run great other than that. Anyone ever had this happen?

 

I dunno about a pop then grind but the auto ORs hill assist control has been reported to act strangely.

 

This is my first Toyota. Never had an auto trans act this way. I shot a vid and sent it to my dealer. I’m sure I will hear something Monday.

 

It's the abs system reacting due to hill assist .

 

Yeah that’s hill assist telling you to keep your foot on the brake or gas pedal ...don’t let the trans hold you in place

 

Will do...thanks for the replies. I just wasn’t sure.

 

Just make sure you depress the pedal firmly when you are on a hill. If you don't you hear that noise. If you do, it will hold there for a second or two and then it will make that noise.