67 sm420 question

[67ranchhand]

Hello everyone. Got the dual exhaust put on today at the muffler shop and finally got to drive this thing! It drives real nice and good power for a stock 327. My question is, does this trans or the t case usually whine? It’s not loud but you can hear it whine. I changed all the fluids in everything and all the old gear lube looked fine but with no exhaust before, I never heard it. Just curious if this is normal for these or do I have an issue? Truck has 102,000 miles on it. Thank you.