Question: Mercon V?

[Laynesman]

Can I use 'Mercon V' automatic transmission fluid for my 08 duramax?

It says use in auto and manual transmissions and power steering on the label, and I realize its probably not the top of the line as far as products go. I just need to know if it is okay ( not detrimental ) to put in for now. Thanks for any help!

 

[calewjohnson]

I would say yes, as long as it meets the TES-295 requirement or whatever your model year requires (IIRC DEXRON VI).

I know for me, I need DEXRON III, the dealer put in VI and said it would be fine, but for my model year, Allison specifically says not to use the VI. So I did a double flush with Mobile Delvac ATF.

Good luck.

Cale

 

[btfarm]

No. Do not use it. And for that matter Allison does not recommend Dex VI. Use TES 295 approved fluid. Transynd or Mobil equiv as mentioned. Unless yo have a built trans.

Sent from my SCH-I535

 

[calewjohnson]

No. Do not use it. And for that matter Allison does not recommend Dex VI. Use TES 295 approved fluid. Transynd or Mobil equiv as mentioned. Unless yo have a built trans.

Sent from my SCH-I535

Actually, DEX VI is what you will get when you go to a dealer nowadays. Allison put out a serial number list with a date starting in 2007 that was OK to use DEX VI since GM switched from DEX III. Factory fill now is DEX VI.

Trust me, I argued with the yahoos at the dealer, since DEX III is the recommended fluid for all 5-speeds.

Cale

 

[Magnus]

The Dex 3/Dex 6 issue has to do with seal material used. At a certain point they changed seals and now Allisons are Dex 6 compatible and come dex 6 from the factory, hence the specific mfr date referenced.

That said as long as you're changing do a TES-295 compatible fluid in trans transfer case and power steering and be done.

 

[Jbenso127]

What would be the proper fluid for an early 06 6 speed Allison?

 

[Magnus]

Dexron 3 is the Chevy fluid, but Allison has their own specification known as TES-295. If you flush and fill twice with any fluid that meets TES-295 you'll be able to run that fill for up to 100k miles and even at that point the fluid may still outperform other lesser tranny fluids.

The official TES-295 is licensed under the name transynd.

There are other good fluids too, and I personally run Schaeffers 204SAT bought locally for $130/5 gallon bucket. It has the best cold weather startup performance I've ever seen and at that price I did the whole truck (trans, xfer case, and steering).

Most people here will tell you to buy some transynd, and that is the official word from Allison.

 

[btfarm]

Mobil has TES295 synthetic and is Allison endorsed. It's a bit cheaper than Transynd but not much. I paid $225 to my door for a pail but I know I have the right stuff in it.

Sent from my SCH-I535