Transmission Fluid Change Question

[John Galt]

Originally Posted by JCL

Do you think they changed their mind or did they change the transmission?

GM uses the exact same transmission as the early E53's that supposedly have lifetime fluid. GM suggests changing the tranny fluid (with DexIII) every 50k miles under the following conditions:

Change automatic transmission fluid if the vehicle is mainly driven under one or more of these conditions:

• In heavy city traffic where the outside temperature regularly reaches 90F or higher
• In hilly or mountainous terrain
• When doing frequent trailer towing
• Uses such as high performance operation

If you do not use your vehicle under any of these conditions, the fluid and filter do not require changing.

If the manufacturer of the transmission suggests 50k mile fluid changes under moderately heavy use, I think I trust that more than I trust BMW's "lifetime no matter what" approach.