I recently took a test drive with a 2008 equipped with a factory exhaust brake, we had over 4000 pounds in the back going down a steep grade.

The truck did not increase speed at all on the grade , in fact it kept slowing down, i was really impressed..

Will a PacBrake on my 2004.5 automatic give the same performance as the 2008 automatic with the factory brake???

Also is there any difference in the exhaust brake performance on a Manual Transmission compared to the Automatics....??

Thanks

 

As far as performance it should be close.

As to the trans, no. It will need help to be as effective as a manual. It can be but not totally stock.

 

Don't forget on an automatic you need to be sure the TC is locked up or the fluid will get hot pronto. Find a transmission controller to help in that area!