I THINK I had a 2003 or maybe 2004 Frontier with the same engine, but it was 4WD, when I bought my 17ft HiLo new in 2007. We pulled that trailer up to the top of Mt Graham (10,000ft) in Arizona, for its maiden voyage. And then, we took it to Colorado over Monarch and Red Mountain Passes (11,000+ ft). Uphill, it was in 1st gear all the way and bouncing off the rev limiter just to keep up with the heavy trucks.
I decided I needed a bigger truck when I saw the temperature going up on the 13 mile 7% grade out of Camp Verde here in the summer.
I bought a 2005 F150 with the 5.4L Triton engine, 4-speed transmission and tow package. It had a 3.73 axle ratio. That truck pulled the trailer all right, but it still dropped into 2nd gear on those same uphill runs.
Now I have a 2014 F150 with the 3.5L Ecoboost engine, 4WD, tow package, and a 6-speed automatic. It has a 3.55 axle ratio. That truck never drops below 4th gear on those same uphill climbs.
My advice is, don't try to tow with an underpowered tow vehicle.
- Jack