What Type Of Transmission Fluid To Use

[lumberjack890]

Doing a fluid change (not flush) on my 4L60E with no prior service as far as I know. At 287k miles.

It takes Dexron III, but I can't seem to find any at my local auto part stores. I've heard that Dexron VI is compatible but which brand showed I get?

The one I'm trying to decide between is the Castrol Dexron VI/Mercon V Full Synthetic AT Fluid and STP Dexron VI AT Fluid.

Feedback is greatly appreciated

2001 GMC Yukon 5.3 V8

 

[PNWYukon]

Found this on Bob is the Oil Guy Forum: During early 2005 General Motors released a newly developed automatic transmission fluid (ATF) for the factory fill of all GM Powertrain stepped gear automatic transmissions. The new fluid provides significantly improved performance in terms of friction durability, viscosity stability, aeration and foam control and oxidation resistance. In addition, the fluid has the potential to enable improved fuel economy and extended drain intervals. Since the performance of the new fluid far exceeded that of the DEXRON®-III service-fill fluids available at the time it became necessary to upgrade the DEXRON® service-fill specification in order to ensure that similar fluids were available in the market for service situations. This latest upgrade to the service- fill specification is designated DEXRON®-VI. Since General Motors introduced the first ATF service-fill specification in 1949 it has been periodically necessary to upgrade the specification. This upgrading process ensures that available service fill fluids are of an appropriate quality for use in transmissions that have been designed around the factory fill fluid performance. It should be noted that, as with previous upgrades, DEXRON®-VI fluids are designed to be backward compatible with earlier transmission hardware. More importantly, earlier type fluids are not forward compatible with transmission hardware that was designed to use DEXRON®-VI fluid, i.e. DEXRON®-III is not compatible with the most recently designed transmissions, and the use of these earlier type fluids could result in transmission damage. All current calibrations and certification tests are now conducted with DEXRON®-VI ATF. DEXRON®-III fluids should not be used for these applications where the owners manual recommends the use of DEXRON®-VI. GM does not license or support obsolete ATF specifications or the use of fluids that are being marketed against cancelled specifications. All DEXRON®-III licenses expire at the end of 2006 and will not be renewed. Beyond that date GM will only support the use of DEXRON®-VI fluids for use in Hydra-Matic transmissions. Fluids sold in the market after that date bearing claims such as “suitable for use in DEXRON®-III applications” or similar wording should be avoided. DEXRON®-VI licensed fluids are fully backward compatible and can be used in all applications covered by earlier GM ATF specifications.

 

[bigdog9191999]

pretty sure brand is irrelivant just as it is with dex 3 . use the brand that you are comfortable with and call it a day. i know when i had the trans rebuild in my 02 he flushed it and put 6 in it. and all the information i have seen confirms what is in the post above, that the 6 is compatible backwards with no issue, but the old stuff is not good in its place.

 

[OR VietVet]

Dexron VI is compatible and will be just fine. It is a better fluid than the Dexron III. It is an upgrade.