I have a volvo VNM630, 2012, 564000 miles, I have a RETARDER TEMPERATURE HIGH, on my screen, anyone can help me.
And check your oil pressure as well in both engine and transmission. If they agree along with your axles you are ok. Something is going on. Im inclined to follow Boneebone here for sure. In my day we use Jacobs over the Pistons the hard way. Never had em fail unless the fuse box got loose somehow. In the meantime turn off the retarder and get to a shop where you can safely check the oil levels.
The only retarder that can get hot is the euro electric eddy retarders. They dump the heat in heatsinks. Otherwise it wouldn't make sense to me why it would warn of that. Retarder (mechanical engineering) - Wikipedia
I have a volvo engine D11 and volvo transmission, my truck is automatic with I Shift. I don't have any error code
It looks like it's an electric retarder in the transmission. Could be a dirty heatsink, clogged oil cooler, or something of that sort. It could just be that you're using it too much for it's specifications. Could just be a simple hydraulic retarder.
Would it be possible you have a factory installed pto Set up and have left it on not knowing. and thats why its calling retarder temp high.