- Joined
- Apr 3, 2021
- Messages
- 27
I put Mobil 1 75w90 in my F150s front diff when I last changed it and went to vacuum it to replace it with amsoil 75w90 but my cheap hand pump just wasn’t cutting it so I bailed halfway through and added a quart of amsoil to bring it back to the correct level. Is there any harm done with combining different brand diff fluids like that?