Said It Here

Passenger side transmission axle seal leaking after replacement

Differential seals often feel slightly too large for the bore or difficult to seat squarely, which leads to improper installation during CV axle replacement. This mistake causes transmission fluid to leak slowly or dump completely out within a day.

What people tried

Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.

  1. 1
    Replacing and reinstalling the transmission seal
  2. 2
    Ensuring the seal is pushed flush with the lip on the flange

In their words

Unedited, grouped by where they were said, most upvoted first within each place, each linked to the thread it came from.

r/MechanicAdvice1 person · September 2026

after replacing my CV axle on my 2010 honda civic my transmission started to leak slowly from the passenger side transmission seal.source ↗

I went to autozone to get the replacement seal and installed the seal and the next day all of my transmission oil leaked out.source ↗

I've come to the conclusion that I am not putting in the seal right.source ↗

AlternativeOccasion2 · r/MechanicAdvice · 2 upvotes
r/autorepair1 person · September 2026

I can't seem to get the diff seal to go into the bore, it feels just a little too large, despite being identical to the one i removedsource ↗

JC121 · r/autorepair · 1 upvotes

Where this came up

People with this problem also raised