Don't know about Cottonwood Pass, but went through Monarch about 3 years ago. It was pretty steep, we had just gotten the 5er then & the truck we had was a gasser. Had to stop about 3/4 of the way up & let the engine & transmission cool off. Plus we stopped 2-3 times on the way down to let the brakes cool off (didn't have problems, & didn't want to). Now we've got a Dodge & with the Cummins I wouldn't hesitate pulling that pass, especially now that we've got the Cummins & exhaust brake! Awesome scenery & if you've got the time there is a gift shop & restaurant at the top. Also near there is a place where the Indians used to run the buffalo over a cliff to stock up on meat. We stayed at Ridgway SP for about a week + & had an awesome time. The movie True Grit (the one with the Duke) was filmed in the area & it's near Ouray, Silverton, a lot of places to explore & things to do.
