[Ramblin Fever]

Welcome!

3K RPM's at 50 mph doesn't sound unusual to me, I have the same year, same engine as you, and I live in the Rocky Mountain Region. I'm hitting 3k rpm's at the base of the mountain, by the time I top most mountains, I'm hitting 4k rpm's.

Nothing unusual here.

If you're use to having lived in the flat-lands, you're just not used to allowing the engine to work a bit. 3-4k RPM's on the 3.2L's is harmless, I very RARELY ever take it past 4k rpm's though - as it really serves no purpose.

This engine is designed to put out optimum power in this range.

Two things you can do to help stay in the correct power band, if you notice the truck downshifting quite a bit on an upslope, manually shift down to 3rd gear if you're within the 45-50mph range.

Otherwise, your "Powermode" button serves as the "O/D OFF" button persay, what this does is keeps your transmission on the up and up as to which gear is appropriate for the speed your going and the load on the transmission.

I would NOT recommend manually shifting to 3rd gear if you're at 55mph+, however you CAN leave the "Powermode" on at all times and it won't hurt a thing. It acts as the "brain" if you will, in helping the tranny decide what gear is best for the slope you're on.

I climb the I-70 corridor quite frequently, sometimes climbing into the 9-12k feet range, I typically push the "Powermode" button at the start of the mountains, leaving the lever in the "D" selection.

There are some grades, i.e. Loveland Pass, where I manually shift down to 3rd gear, and turn "OFF" the Powermode feature.

As, leaving the "Powermode" feature ON with the gear shift in 3rd, the truck will have a tendency to overwork itself and shift down to 2nd at 45-50mph - sending your rpm's to 4,500.

In this instance, I'd rather go a tad slower in 3rd gear, versus trying to keep 50mph in 2nd gear.

I have never been to Hawaii, but I'm guessing most mountain passes may not be as steep as Colorado's. Thus, 2nd gear is probably not something you'll need, as I've VERY rarely ever used it myself - when I have, that's with pulling our 4K# boat.

I would not be driving mountain passes simply in the "D" range if you feel constant up and down shifting, and/or engine lugging, you WILL burn up the transmission.

Keep in mind, you have a heavy truck (i.e. 4k#) mated to a somewhat weak, but strong willed engine.

Living in mountainous regions will truly teach an owner of the importance of preventative maintenance, i.e. spark plugs, filters, belts, hoses, transmission fluid, etc. as one will learn quickly if their vehicle is not in tune.

If your plugs have over 40k, change them; also, if you haven't done it yet, your hitting the time of needing a new timing belt, waterpump, and probably O2 sensors (there are 4 on this truck) - those items alone, though not cheap if you take it to someone, will make a very noticeable difference.

We have the 4L30-E GM Transmission, a tranny famous for complete failure if overheated, low on fluid, and/or dirty fluid. I currently just rolled over 158,800 miles on my truck, original transmission, and I change the fluid every 30k miles on a flush or every 15k miles on a partial drain/refill.

If it's been more then 30k on your transmission since your last fluid change, do a partial drain/refill and keep that fluid clean, can't stress that enough living in the mountainous regions.

There are still a LOT of older Rodeo's here in Colorado, they may have a weak output engine, but the 3.2L sohc are very strong willed and sturdy built.

FWIW - I've just recently gone through a major tune-up myself; i.e. 2nd timing belt and waterpump. New NGK sparkplugs, fuel filter, transmission serviced with new fluid and filter, all new O2 sensors, EGR cleaning, PCV valve replacement, etc. it still hits the 3-4k rpm range when climbing, but feels strong while doing it.