Does your old dog grumble?

So I’m not after vet advice but I am just curious. Our older dog turned 10 this year and unfortunately as he was getting off the couch one night he partially ruptured his cruciate ligament which he received prompt treatment for – they found through his x-rays however that he had pretty bad arthritis in his hips which we are totally up to date on a treatment plan including pain relief etc

Brings me to my question he does this like grumble sometimes ? It’s not a groan or a moan it’s a grumble he doesn’t appear to be in any discomfort sometimes he does it when he’s asked to move over or when he lays down fully or even when you just go for a pat he grumbles.

Their are no signs of distress or discomfort it’s more like he’s being inconvenienced 🤣 he’s always had an expressive face but he’s always been a very quiet dog and this only started after his injury. Has this happened to anyone else? I’m going to ring the vet in the morning anyway but I just wanted to see!