So if you had a K&N and a 6637 both for no additional cost, which would you put on?

I've been running a 6637 for about 25 K miles, and figure it's time for a change. Picked up a replacement but haven't installed it yet, then ordered some performance goodies. The goodies came with a K&N, so I've got both available (and the original airbox for the K&N).

So, which would you put on, and why?

With the other goodies I'll be putting on the truck, it would be a good time to add an auxiliary transmission cooler. I'm thinking of one of the simple passive coolers, probably stuck somewhere between the frame rails and behind the radiator. Do I need to be worried about overcooling the fluid? Truck lives around Baltimore, and runs mostly on highway with light loads. Thoughts?

 

I would be willing to bet that around here most folks swear by the 6637 filters...I know I do

 

x2 .. 6637 wins ,,

 

I have a K&N. It works and works well. They do flow more air than the 6637 but they also let a lot more dirt get buy and that is not a good thing for your turbo or motor. I live in the city so I rarely see any dirt roads so I am in no rush to switch to the 6637 that has been sitting in my garage for about a month now but it is something that needs do be done if I want my motor to last as long as possible. And the 6637 is cheap enough if you know where to get them.

Air Filters and Breathers - FleetFilter Online Store

 

6637 k@n will dust your turbo

 

6637 wins no question! The K+N filters are bad news. The drop in K+N are REALLY REALLY bad news! Sell it on ebay!