I notice that when I drive up Vail Pass heading east, my Auto Tranny will sit right at 5k, just a few notches below red line and hold itself there, even when I barely let up on the gas. I heard that a Toyota tranny knows when to shift itself, but I'm surprised at how long it will flirt w/ the redline. This is w/ the OD/off and driving w/ the goal of maintaining 55/60 mph on a high mountain incline. Any thoughts on how hard this is on the engine? So far, it's happy at 140k.

 

with od off and at that speed on a hill, it probably isnt trying to shift, it needs to exploit as much power as possible

 

Well, if your OD is off then it won't shift at all. I am pretty sure you have an 4 speed transmission so in your case it's probably just sitting in 3rd at the high RPM. From my experience ('96 4Runner) my tranny does the same thing in 3rd with OD off, but with OD on (going uphill 65 mph) it will stay @ 5000 for 3 seconds and then shift, but it WILL shift.

 

oops, let me clarify...it's at almost 5k rpm, in 2nd gear, however the gear selector is in D. If I let up quite a bit on the gas, it will shift into 3rd. Again, my curiosity is more about the RPM's. Do I need to regulate the tranny's desire to shift or not shift in these situations, or let good ol' Toyota Research and Design handle this?

 

if the tranny hasn't shifted itself, it has not decided it needs to shift... given your conditions, that rpm doesnt seem that bad.... lets jsut say i beat my truck, and i can go well past 80 in second gear, yes it revs high, but isnt close to blowing itself up....

 

I would say that you should just take a good judgement. If the engine sounds nice and healthy at that RPM I would say just let it do it's thing. But if it's not all that rosy, maybe step off a little and let the speed drop just to spare the engine.

On my 3.4L, it roars very nicely at 5K and I usually keep it there so I get that extra high way UMPH (and probably because I am an idiot and prefer UMPH over MPG, hehe). Never had any problems and I don't think you will either.

Marko