Hey Guys. The stock transmission found in the new Duramax trucks, the automatic 4L80E... How much power can the stock unit handle? Horsepower and torque? Please advise.

 

The automatic in the Duramax's are allisons. They should be able to handle 400 or 500 horse if I remeber correctly.

 

I agree with Scott, that you do not have a 4L80E tranny. They were used in the pre Duromax and pre 8.1 engines. I don't know if some version of itis still used in the smaller engines. It was a good tranny, but no wheres near the Allison. If you have a Duromax you have the best of engine tranny combo. If you plan to hop up the Duromax, try one of the after market kits advertised, as they have been tested with the Allison and should be a good bet.
Mel

 

Hi. I want to know about the factory 4L80E...

 

The OEM Hydro-Matic 4L80-E is rated at 461 lb/ft of torque.

 

Done... 4L80E swapped into 07 Tahoe