View Single Post
  #80  
Old 12-15-2012, 09:13 PM
Dalmat3 Dalmat3 is offline
Registered User
Location: Vancouver Canada
 
Join Date: Dec 2012
Posts: 5
Mein Auto: 95 740il
I've replaced 2 or 3 times trans fluid -admittedly not on 7 series. Each time tranny quit short time after. If it says "lifetime" -trust it is
Seals in the original tranny become quite acidic due to fluid wear. By putting low ph (new) fluid into tranny, we cause more trouble by allowing those old seals to suddenly get exposed to new fluid with radically opposite ph factor. This is what screw them seals up. If I had to change I'd change half fluid only, so that chock of new fluid wouldn't ruin the tranny too soon
Reply With Quote