Bad news .
The axel will have to come out & get split.
If it is a manual tranny then no worries.
If it is a hydro then it will be a PIA
The axel is held in by retainer clip.
Can be an E clip or a round wire clip
Usually when they pop off you need to put a thrust ( high tensile) washer between them & the case cause they chew the case out.
Try to find the remains of the retainer because it can get munched up & do big damage.
On hydro boxes they must be cleaner than clean and covered with a damp cloth while open as a small amount of dust kills them in no time flat ( the Y-Tube monkeys usually fail to show their repairs failing in a season or less ).
