TH400 whine

[Formula1973]

Hello Everyone-
I have a brand new (less than 500 miles) TH400 transmission in a 73 Formula.
When decelerating, there is a slight whine. Nothing too loud and only when decelerating.
Is this normal.
Probably nothing, but bothered me enough to ask the experts.

 

[melsg5]

No it's not, if it is from the transmission take it back to the shop that did the work.
Did you check the fluid level when fully warmed up and after selrcting each gear position and returning to park
Are you sure the noise isnt coming from the differential?

 

[Formula1973]

Yes, I checked the fluid as you wrote above, all looks good.
Does not sound like the differential, that is new also.
Can you upload videos here?

 

[melsg5]

The differential is the typical source of a whine upon deceleration, ring and pinion issue.
If you decelerate and shift into neutral is the noise still there?
How skilled was the person who did the overhaul of the differential, I assume that is what you meant by new.
What weight and type of oil was used in the differential?
It should not be synthetic and in some cases the whine can be minimized by using 85w140

Advance Auto Parts - Down for Maintenance

You can try to attach files but a video typically doesn't help much in determining the source of a noise.