668 is the updated 295 spec fluid. While 668 has some extra goodies....both it and 295 will perform EXCEPTIONALLY well in a pickup truck Allison and will be more than solid in a stock transmission/hp set up. Use either with confidence and they are both compatible with each other.

 

I run Schaeffer's 204SAT All-Trans Supreme full-syn fluid in my built 6spd...

All-Trans Supreme® | Schaeffer Oil

Schaeffer's ALL-Trans Supreme is a superior alternative transmission fluid to Dexron III, Mercon, Mercon V, and Allison C-4 type fluids.

www.schaefferoil.com

 

Same here. Will not find a better product.


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Is your transmission stock @Vroom_vroom ?

 

If it’s stock and never been touched, Dex3 should be used. Even though GM says Dex6 is backwards compatible, some of the seals and sealing rings internally don’t really get along well with the Dex6. That’s last I knew/remember from Allison people anyway. If it’s never been touched or updated with the compatible parts, I would stick with the Dex3 compatible fluid.

 

Was 2006 the year the seals changed Matt?

 

Yes, when they changed to the 6spd the way I understood

 

My trans is stock never touched. So even here some of you guys say 668 is ok but another says it’s not good on seals. This is what makes me confused.

 

668 is okay, Dexron 6 might be an issue. 2 different fluids. The 295 and 668 specifications are from Allison themselves. Dexron specs are from GM. The Schaeffer product Rob is using is a Dexron 3 product for example (a very good one at that).

 

So is the Shell 668 I posted alright of an oil?

 

Seals where changed when the 6spd was introduced in 2006...

 

It's excellent.

 

Thanks all for replies.

 

Just a bit of an update that makes me more confused, I called a dealer and they say use their DEX VI that’s what they put in all their trucks.
Problem is that Shell668 I was looking at is getting discontinued at where I found it and afraid of mixing fluids later on. I’m thinking I should use TES295 from all the reading I’m doing but finding it hard to find around here, any suggestions on readily available fluid brands. Keep in mind I’m in Canada so maybe Piper can be of some help. Thanks

 

TES-668 has superseded/replaced TES-295 fluid... The dealer has no options other than Dex IV.

 

The best fluid for a stock trans other than my choice of Schaeffer's would be Mobil Delvac ATF...

On/off highway - Mobil Delvac 1 ATF | Mobil™

Mobil Delvac 1 ATF is a fully synthetic fluid recommended by Allison Transmission, Inc. approved against the Allison TES-295 Specification.

www.mobil.com

 

668 fluid can be found at most truck (big) dealerships as well as 295. The 295 fluid is on the way out, being replaced by 668. Both 295 and 668 are FULLY compatible with each other and will also not do anything bad if they are mixed with Dex6 while you are in the process of changing over.

As Rob mentioned, a GM or light truck/car place will only have or recommend Dex 6.

I'd try Rush Truck Centers (International dealer) or the Freightliner dealer up there (I think it's called Francis now). International has a fully licensed house brand (Fleetrite) of 295 that's as good as any other 295 fluid. Your also likely to find the actual Transynd branded stuff (Castrol) in either 295 or 668 at many dealers. Any dealer that does a lot of school bus or government trucks (snowplows etc) is likely to have it since those vehicles are almost 100% Allison automatics.

Don't get hung up on whether its 295 or 668. Either is vastly superior to Dex6, especially in the cold and are fully compatible with each other.

 

668 fluid can be found at most truck (big) dealerships as well as 295. The 295 fluid is on the way out, being replaced by 668. Both 295 and 668 are FULLY compatible with each other and will also not do anything bad if they are mixed with Dex6 while you are in the process of changing over.

As Rob mentioned, a GM or light truck/car place will only have or recommend Dex 6.

I'd try Rush Truck Centers (International dealer) or the Freightliner dealer up there (I think it's called Francis now). International has a fully licensed house brand (Fleetrite) of 295 that's as good as any other 295 fluid. Your also likely to find the actual Transynd branded stuff (Castrol) in either 295 or 668 at many dealers. Any dealer that does a lot of school bus or government trucks (snowplows etc) is likely to have it since those vehicles are almost 100% Allison automatics.

Don't get hung up on whether its 295 or 668. Either is vastly superior to Dex6, especially in the cold and are fully compatible with each other.

Fleetrite is $152 gal. 😵‍💫

 

Thanks everyone, this is a great place to learn.

 

Summitt Racing has the Mobil Delvac 295 Allison approved ATF (may be 668 now) at a decent price. Last time I ordered from them, purchases over $100 get free freight, may have changed but worth looking into.

 

Shipping is never free to Canada, and shipping costs are crazy……sometimes as much as product.

 

04 LB7 somewhat lost in the woods it’s was cold dark and cold transfer case had a tear in it an inch wide and a foot long across the top Stuck in 4LO made the mistake of shifting to reverse when I coulda rolled over the saplings brush and rocks ahead of me because shifting back to drive with the case having lost so much structural integrity caused mayhem with the driveline and almost ripped it out of the gear box breaking the rear seal almost seoerating the trans and case transmission fluid gushing I think I lost 10 quarts instanly what was left in it wasn’t enough to spin the torque converter. Snow was beginning to fall no 4x4 at this point phone blowing up with texts that started with hey babe it’s getting late hope your ok we’re now hey ass hole I know your with that girl again
I had to get off the mountain
Long story short I pulled about 6 quarts of oil of the engine ran it down the tranny dipstick tube crossed my fingers it was not pretty was not a comfortable ride home but it worked It’s a Chevy man I think I coulda peed in it and made it home. I think your shell product will do just fine