Hesitation in 3rd gear

[draggin49]

My 1932 Ford v8 roadster is running the stock transmission.

Occasionally when shifting from 2nd to 3rd once in 3rd under heavy pedal the car hesitates and almost revs up like it’s in neutral for maybe a second then goes back to normal. Doesn’t do this in any gear but 3rd . Outside of that the motor /trans seem to work really well.

I am gonna check trans fluid tomorrow, if not that maybe the trans has issues?