300 TE radiator repair or replace?

[dka-66]

I have a 1989 300 TE with the m103 engine.

Water is leaking from the radiator tank where the upper transmission cooling line attaches, it is leaking where the brass fitting go's into the plastic tank.

Is it better to replace or to try to get this repaired?

In a thread I found someone (david s poole, If your out there) mentioned "aluminum shrinks over time and temp cycles so won't flow enough at idle.usual life is 5-7yrs."

I have never heard of this before and was wondering how many of you out there have heard this......and does it indeed make that big of a difference?

Here is the link to that thread radiator question