Allison 1000 - LBZ Duramax ATF Choices

Apr 19, 2021
I know this has been discussed countless times, but most of the threads are many years old now, and I want to make sure I am not overlooking an important detail. I have a 2006 LBZ Duramax with the Allison 1000 6-speed transmission. The truck has around 60k miles and the ATF has never been touched. I am looking to do the double drain and fill method to get some fresh fluid in there. I am assuming the tranny has Dexron VI in there now, but I am not for sure. I plan to drain the pan and change spin-on filter, drive truck for 20-100 miles and repeat. So I have a couple questions...

1. What fluid can I safely use? I use Valvoline MaxLife Multivehicle in a few other cars I have, so I'd love to use that, but I read a lot about TES-295 and now TES-668 spec fluids. I know I am being cheap, but the official stuff is PRICEY. Any good bargains on that stuff out there? What about this stuff on Wal-Mart's website. Sinopec Multi-Vehicle HD ATF

2. My research says to just to a double drain and fill, no need to drop pan and change internal filter. Is this still best advice?

Thanks for all the knowledge that BITOG has brought me over the years.


Staff member
Aug 20, 2003
Naperville, IL
TES-295 is a very robust ATF and is meant for your 1000, so I would stick with what Allison specs. Yes, it's pretty expensive, but with the miles you put on it's a one-time event. You can also use TES-389, but the change interval is shorter.

You only need to change the spin-on. Make sure you get a genuine Allison filter, as they body thickness makes the filter much stronger than others. If you would, cut the old spin-on open and show us what the filter caught.
Sep 6, 2007
Here is knowledge from Dmax forum, the author is also a member of BITOG:

It is not about the procedure but the fluid.
You can visit the forum yourself and read up on the changing process.