Heads up to anyone with a 2006 Duramax diesel?
 

Seen a few guys mention they have a 2006 Duramax trucks here so I figured I’d give some forewarning about a pretty dumb screw up by GM, I figure if it even saves one guy a few bucks on not having to replace some transmission seals then it’s worth it.

Had a seal start leaking on my Allison transmission in my 2006 2500HD Duramax. Owner’s manual said to use Dexron IV. Decided to just in case see what all the fellas on the Duramax forums say to use. Turns out Allison released a memo stating any 2006 6 speed Allison transmission paired to the Duramax with a serial number before 6310670488 for Indianapolis build and 6320784373 for Baltimore (most Pickups) have seals in the transmission that are NOT very compatible with Dexron IV, and it will eventually cause seals to fail. Those serial numbers also generally coincide with the start of the 2007 classic Duramax trucks, so majority (if not all) 2006 trucks are not recommended by Allison to be using Dexron IV, and should be using either Dexron III or TranSynd (or any TES-295 ATF). Supposedly, running those fluids will both save your seals, possibly extend the life of your trans, and if you’re running a tuner, will also help your trans deal with the extra power a lot better. As well, never allow a trans shop to flush your Allison, supposedly it can seriously damage your transmission, only drain, change the external filter, and fill.

Anyway, I suppose if you have had seals fail on these before, this might explain why. Hope this helps for any of us still clinging on to these old piles of junk. Lol

Thanks for the heads up. I have a 2007 Duramax - Classic.

Your truck should be fine then.

Best Duramax ever imo.

Sold my 07 LBZ for a new LML and regretted it ever since.

Take care of that truck!

I have a 07 duramax classic as well. Bought a2018 but can't seem to let go of the 07. Best truck I have ever owned, bought it new. Don't think the 2018 will prove to be as good but here's hoping

I've been using Transynd for a number of years now in my 06 LBZ. It really is good stuff and worth the cost. Didn't realize it help prevent those seal issues though. Thanks for the heads up

Yep. Don't use it much in the winter. 150,000 klicks. No rust and no issues.

I have a 2008 duramax 336000 klm's still looks like new . I have had many come up to me and ask if I would consider selling . Great truck if you look after them.

I have a 09 d'max closing in on 500,000 km, still looks like new if you stick a finger in one eye and squint hard with the other. Great truck but an expensive sumbuck to keep in reliable shape. I'll never buy another diesel pickup.