!997 Silverado 4L60 Transmission

My son has a 1997 Silverado that has started something new: the transmission howls and has fluid that is brown. It was OK last time he checked fluid at oil change time last month. I think it could be cooler contamination but the radiator is relatively new. He reported that the truck still drives the same, just noisy.

Any ideas?

why do you think rad is newer? did you change it?
if you did, why did you change it?
i had a 3yr old rad fail and dump coolant into trans oil.
changed rad again and put in used trans. ugh. not a good week

It is a 2-2.5 yr old radiator. Figured it might be that fluid and antifreeze could cause a brown soup if it gets mixed. I will have him check the antifreeze today to see if it is muxed up.

I am afraid it is a main pump or clutches that are toast. sometimes it is something simple. Looking for tips before we get too far down the wrong path.

That transmission is on the Grim Reaper’s short list. It is gonna die, and soon! Brown fluid is a bad thing! If you aren’t seeing any brown fluid in the coolant, the radiator is probably OK, the transmission is not!