spontaneous shifting in an auto

[spidydude]

So today my mother's GMC Envoy XL has an auto box in it and lately it has been making noises and shifting gears very randomly, as today she shifted into first at about 50 from 4th and almost did some damage to the engine. She also stopped and the engine went down to almost 200 RPM! it was ridiculous. there is no manual feature, and it occasionaly makes strange noises (like grinding gears) when it shifts up, but never when it shifts down.

any ideas?

[Silent1]

it's broken

HTH

[spidydude]

ahh, i never would have guessed

[Silent1]

Good job i'm here to provide out of hours support then isn't it

[Trooper2]

spidydude said:

So today my mother's GMC Envoy XL has an auto box in it and lately it has been making noises and shifting gears very randomly, as today she shifted into first at about 50 from 4th and almost did some damage to the engine. She also stopped and the engine went down to almost 200 RPM! it was ridiculous. there is no manual feature, and it occasionaly makes strange noises (like grinding gears) when it shifts up, but never when it shifts down.

any ideas?

Get it in and have the DTCs read.

[SplatSpeed]

check the oil

if its low this can happen

if it still happens after oil is topped up

guess what