GMT800 5.3 was struggling up the grapevine (CA)

[Mark-23]

 

You can pull the shifter all the way down until its in 1, then shift the shifter up one click to 2, then shift to 3 and then D.

 

Well I know how to shift! Duh!!! But what does drive 1 through 3 do?

 

How does it affect my performance up and down?

[Mark-23]

Or, you just leave it in "D" and let the transmission do the downshifting. You mentioned that newer GM trucks are going faster than you; that's because GM keeps increasing the horsepower on that motor. If yours is like mine ('05 Suburban), it makes 295 HP. I think the newest 5.3's are making 355 HP. That's a big difference.

 

I left it at D. And I had my foot which is heavy pressed all the way down, and that's when it would work up the engine and go faster just to maintain 70-75mph

 

The newer GMs were going atleast 80mph if not 90 and god did my blood boil.

 

How does your 05 perform on that route?

 

How should I use the lower gears and when?

[Chris]

Well I know how to shift! Duh!!! But what does drive 1 through 3 do?

 

How does it affect my performance up and down?

The 3 let's the transmission shift normally in gears 1-3. No overdrive. 2 will start in 2 but downshift to 1 if needed, but generally give you second gear. 1 will only give you first gear

[r1byker]

My '05 does okay but it's definitely working on the uphill sections. I don't bother trying to keep up with anyone; I'm happy to just run at around 65. And just let the transmission do the work for; leave it in "D" and enjoy the ride.