Duramax Allison issue

[ss3011]

Originally Posted by SDT1DYI

Decided to change the screw on external transmission filter during other maintenance work on my 2018 3500 Duramax.
Purchased a well know house brand replacement filter . Immediately experienced down shifting problems. Purchased a GM filter from the dealer @ a 34.00 cost.
Problems ended. Going to purchase a couple of more for inventory.

Be aware if you have late model Duramax tow rig.

Steve Teeter. STK 6380/6283

This is interesting ! Did you change the Fluid when you put the aftermarket filter in ? What happened when you say you had down shifting problems ? Did the problems go away immediately when you installed the GM filter ?

[Ralph A Powell]

Y

Originally Posted by ss3011

This is interesting ! Did you change the Fluid when you put the aftermarket filter in ? What happened when you say you had down shifting problems ? Did the problems go away immediately when you installed the GM filter ?

It's a Allison trans not a GM design and manufactured trans!

[ss3011]

Originally Posted by Ralph A Powell

Y

It's a Allison trans not a GM design and manufactured trans!

Allison was part of GM Hydramatic when the 1000 was developed . The Engineers from Indy work side by side with us in Ypsilanti . When GM went through bankruptcy Allison was spun off but the only Allison trans that remained with GM was the 1000 because it was in most of the 1-ton pickups . I think it's still built in Baltimore . Also Castrol developed the fully synthetic fluid Trans-Max , and later Allison re-named it Trans-Syn . It is a very good Automatic Transmission Fluid

[Mark Lewis]

Would the Trans Syn fluid be better in a 2001 1000 model Allison than the Dexron?

Originally Posted by Mark Lewis

Would the Trans Syn fluid be better in a 2001 1000 model Allison than the Dexron?

Yes! My 2003 has it. Smoother and less trans temp. Walmart is the best deal on approved Delvac Allison syn. I don’t use Castrol...

[monte385]

Originally Posted by Barry Polley

Yes! My 2003 has it. Smoother and less trans temp. Walmart is the best deal on approved Delvac Allison syn. I don’t use Castrol...

Summit's price was the best I found, never checked Wallmart.
Yes trans shifts smoother & runs cooler.

Works so well in the truck I’m tempted to try it in the race car.