Cut off an inch of your long allan key and then just put a wrench on it. Alternatively, I'll sell you my special short allen key for 2005 Corvette diff fluid change for $20, haha
The Allen wrench I used had a ball end for angled application.
Worked awesome.
An old spark plug wrench (or pipe) for leverage on the short end of the Allen wrench.
This might not be possible for 2005.