Acceleration in 4 low going down hill

[Moabman]

I have experienced acceleration while going down steep rocky hill in 4 low, lockers on. Traveling at maybe 1-2 mph, maybe 1000 rpms when all of sudden the engine speeds up to 2500 rpms, moving me faster down the hill, but the hill is not any steeper or rockier. If I hit the brake my engine slows down. This has happened multiple times, kinda scary. Has anyone else had this happen?

 

[Madcowranch]

Hill Descent Mode engaged?

 

[ISFast]

I have experienced acceleration while going down steep rocky hill in 4 low, lockers on. Traveling at maybe 1-2 mph, maybe 1000 rpms when all of sudden the engine speeds up to 2500 rpms, moving me faster down the hill, but the hill is not any steeper or rockier. If I hit the brake my engine slows down. This has happened multiple times, kinda scary. Has anyone else had this happen?

I have had this happen to me when I leave work and due to the lights and no ones around that time of the morning I just put it in 1st gear and let the motor warm up. It will all of a sudden rev up to about 2K rpms and stay there until i hit the brakes then its back down to idle. I thought mine might be a warm up thing but maybe not.

 

[Moabman]

tried it with both Hill decent both on and off, same problem. The engine was on for over 1 hour before this started happening. So the engine was not cold

 

[19-Kilo]

ECU automatic rev to keep the RPM up and not lug the motor?

 

[BIRDMAN]

put the PRND321 in 1 if you're going down a hill. 1st gear is very short in 4Lo, sounds like you're experiencing a harsh shift in to 2nd gear in which will reduce engine braking and let you speed up(for lack of a better description)

 

[Raptorguy21]

put the PRND321 in 1 if you're going down a hill. 1st gear is very short in 4Lo, sounds like you're experiencing a harsh shift in to 2nd gear in which will reduce engine braking and let you speed up(for lack of a better description)

Exactly....OP are you in actual 1st on the indicator or in D?