I like to pay attention to the owner's manual. if you think you have extreme service, pay attention. if not, looks like no need.
that being said, I am about to drop the pan and change the filter on my son's 08. but it has a big dent in the pan, so i have a new pan on the way, and wonder if the dent racked the filter housing. there is also a TSB on at least the 08 for a magnet which is too weak to hold all the filings. the TSB says add a couple magnets (in specific places) when you do have the pan off.
will use an oem filter and full synthetic DEXRON VI.
old wive's tale on the if you did not change it, don't, if you think your tranny is held togetther with old gunk, you need a new one anyway.
and don't let the oil shop charge you for a flush and go without changing the filter or dropping the pan.
this is the TSB I talked about.
Bulletin No.: 08-07-30-040C
Date: July 25, 2012
Subject: Information on Normal Maintenance or Warranty Service for 4T40, 4T45, 4T65, 4L60 Automatic Transmission Oil Pan Magnet Upgrade
2002-2011 GM Passenger Cars and Light Duty Trucks
Equipped With the Following Transmissions:
4T40-E or 4T45 HYDRA-MATIC(R) Automatic Transmission (RPOs MN4, MN5, ME7)
4T65 Transmission (RPO M15 and MN7)
4L60 Transmission and Derivatives (RPO M30 is 4L60, M32 is 4L65, M70 is 4L70)
Do not remove the transmission oil pan unless normal maintenance or diagnosis of a customer concern requires it.
This bulletin is being revised to add 2010/2011 model years. Please discard Corporate Bulletin Number 08-07-30-040B (Section 07 - Transmission/Transaxle).
A new transmission oil pan magnet, P/N 29535617, was released for service. The current square transmission oil pan magnet may become saturated with normal ferrous sediment and the Pressure Control Solenoid (PCS) is now collecting ferrous sediment, making it vary from design. For a given current the PCS electromagnet is stronger, causing the line pressure to be less than needed.
When checking PCS line pressure (refer to Line Pressure Check in SI) and it shows that the line pressure is lower than required (refer to Current-Amps/Line Pressure Chart in SI), for a given current at the PCS or the transmission oil pan was removed (for either normal maintenance or warranty service), only then should the transmission oil pan magnet be upgraded.
1. Remove and discard the original square transmission oil pan magnet and install a new one in the current location (See graphics below for the correct application).
2. Install the second new transmission oil pan magnet in the following location as shown in the illustration.
4T40 & 4T45
Only on 4T65E, the second magnet (left) should be attached to the transmission filter.
If the magnet is attached in any other location, it may cause interference (refer to graphic above).
Note photos from the TSB did not copy.
you should be able to google up the tsb number
oh what the heck.
here you go.