Anyone drive in 3rd in the city?

[AzTruckGuy]

So I am just learning this and I viewed it on Trailvoy, I took my dog out to the park and on the way home, put it in 3rd. Wow I'm not kidding the Trailblazer felt way smoother with no engine drag or the feeling of slow gears. It felt like a completely different Chevy, why didn't anyone tell me this before?

 

[littleblazer]

Huge loss of fuel economy I would guess? My trucks tune is good enough where I don't mind. 3rd for me means 50-55 most of the time and that's pretty high up there in the band for around town... but yes it puts you right in the power curve so more is right there.

 

[AzTruckGuy]

Your kidding right about the fuel loss? I already have bad MPG, so you think 3rds going to make it worse? We shall see since I am imputing my fuel ups on fuelly. In my case my city commutes consists of about 4 - 5 miles of stop and go driving, the highest MPH being about 40 though most of it is about 25 - 35.

 

[Mounce]

Well yeah, making it stay in third of course takes fourth gear away which means to run the same speed the engine is turning more rpms in third than it would in fourth.

Higher rmp generally means more fuel.

Biggest difference you're feeling is probably the lack of delay of kick down to third where that the engine will bog down a bit before the computer decides to switch gears shifting.

 

[AzTruckGuy]

Well yeah, making it stay in third of course takes fourth gear away which means to run the same speed the engine is turning more rpms in third than it would in fourth.

Higher rmp generally means more fuel.

Biggest difference you're feeling is probably the lack of delay of kick down to third where that the engine will bog down a bit before the computer decides to switch gears shifting.

Yes which made me think the transmission maybe needed the shift solenoids replaced, which they clearly do not need to after driving around in 3rd, makes me feel like this what a PCM flash would feel like.

 

[Capote]

Don't do it, I tried 3rd in town for like 2 weeks, that's when I started having a knocking noise. Wastes gas too, as mentioned already.

 

[Sparky]

Driving in 3rd will not cause knocking (coincidental that it started happening then but totally unrelated), but it will use more gas if you're driving at a speed where normally it would shift to 4th.

 

[littleblazer]

A couple years back when I did it I went from high 12s to low 9s...

 

[HARDTRAILZ]

I have done it many times in mountains n such. It just eliminates overdrive and allowed my tC to lock in better for the speed changes.

If the speeds are low enough you dont need overdrive...like your sub-40 city and it will not affect anything even MPG that much if any since in 3rd your rpm will still be quite low.

 

[AzTruckGuy]

I have done it many times in mountains n such. It just eliminates overdrive and allowed my tC to lock in better for the speed changes.

If the speeds are low enough you dont need overdrive...like your sub-40 city and it will not affect anything even MPG that much if any since in 3rd your rpm will still be quite low.

I agree with you, theres misconceptions on what 3rd gear does, when I was driving around in D, I noticed that I was around the 1,500rpm range most of the time, in 3rd gear its the same. So for me to drive it around in 3rd, its more logical for now. I will be inputting fuel info, since I am tracking it. I like the 3rd gear feel, its more smoother and consistent.

 

[HARDTRAILZ]

Locks in better than fumbling with in and out of overdrive when not needing OD. Used to be a standard thing to do for decades back a decade or so. I did it all the time with my first blazer back in the day

 

[shovenose]

Sounds like a great idea. I will try it. When I drive to/from work which is stop & go traffic the whole way for ~5mi the tranny sucks. This thing gets awful MPG in town anyway so who cares lol.

 

[littleblazer]

Stop and go I understand. But most of the back roads I use are 50... so that's 2300 rpms vs 1500. I tried it again today and it didn't really feel great... well it actually just ran warmer is all. Not worth it for me.

 

[HARDTRAILZ]

Backroads at 50 are certainly not city like the OP was referencing in this thread

 

[dkvasnicka]

I have done it many times in mountains n such. It just eliminates overdrive and allowed my tC to lock in better for the speed changes.

You mean your TC locks even when you have the tranny in 3rd? My Saab 9-5 did that but the 9-7X doesn't seem to do that. When I limit its choices by shifting to 3 it just doesn't shift higher and revs higher...

As for the specific scenarios I definitely use this when (somewhat) fully loaded with people and stuff and doing 50 - 60 MPH on steeper inclines. In situations like these when my cruise control is on the transmission first tries it in 4th & locked, then unlocks and when it goes even lower to 3rd I immediately put the lever to 3 because if I don't do that it soon starts to think it could upshift and even lock.... which of course works for like a few secs and here we go again

Transmission lifespan > obsessing over tenths of MPG.

 

[Sparky]

My Trailblazer would lock the TC in 3rd.

 

[dkvasnicka]

I admit I didn't do any thorough testing. Maybe the inclines were too steep for it to lock. But then again why would it try to upshift and even lock momentarily in 4 when in D and not lock when in 3...? Or maybe the slight drop in RPM as it gained momentum and tried to observe the speed set on CC on the incline was actually a lock.
I do not regularly frequent places where I would need to do this.

 

[Sparky]

I should say it rarely would lock the TC in 3 when I had the shifter in D. It would go to 4th instead. If I put the shifter in 3 then it would readily lock the TC.

 

[littleblazer]

See when I tested it today the tc was present but didn't seem to lock. If I let off the gas it dropped almost 400 rpms. Second my foot touched the gas any amount it jumped back up. This was at 45 though and could be due to the tune... my Trans has always seemed a little off and it whines.

 

[Sparky]

Letting off the gas will unlock the TC. That's normal.

 

[Harpo]

I think I read somewhere that 3 would allow the Tc to lock in third as it in D doesn't do that. I have also really tried to get a Tc lock in third gear when in D,it's not possible,trust me.

I also would use 3 on curvy hilly roads around 35-45mph that usually makes the truck hunting gears and make a vortex in the fueltank, but that's probably very individual due to gearing, I got 3.73.

 

[HARDTRAILZ]

When in 3rd it will lock in. When in OD it will lock in. It locks in either if I select that to be my top gear or it will just shift through to the next gear

 

[Harpo]

How do you manage that?, I have tried this numerous times and never had it do this. I even used Torque to monitor Tc slip speed and it wasn't even close to lock in third when driving in D. In my experience it would shift to fourth gear before any Tc lock would happen.

If I as I'm doing now towing my 4400lb tt it will not lockup in third gear if I'm not putting the shifter in 3.

 

[HARDTRAILZ]

It cant shift to fourth with the shifter in 3rd.... As i describeed, I am putting it in third or otherwise it shifts to fourth just like I and you state.

 

[Harpo]

Aha ok, i misunderstood what you wrote

 

[BrianF]

I do if it is stop and go and not very fast paced. I also downshift on the highway all the time. around 80km/h I shift out of od to coast and engine brake. works great. Maybe explains why my factory brakes are still kicking with 198000 km on the clock.

 

[seanpooh]

If I'm in the "city" like NYC where the limit is 25mph and stop signs/lights at every intersection, I'll just drive in 2nd.
I have the PCM tune for the firm shift along with a Sonnax shift kit. The 1-2 shift is killer.

 

[Wooluf1952]

If I'm in the "city" like NYC where the limit is 25mph and stop signs/lights at every intersection, I'll just drive in 2nd.
I have the PCM tune for the firm shift along with a Sonnax shift kit. The 1-2 shift is killer.

Do you just leave it in 2nd? Or do you put it in 1st and then up-shift? If the shifter is in 2nd, the trans starts in 2nd, not 1st.

 

[seanpooh]

I leave the shifter in 2nd. City driving is city driving and driving in 2nd is no deal for me. It makes my trailvoy sound louder with my headers in 2nd anyways

My max mph is 25 in 2nd. If I go past that, I just push the shifter into third.

 

[Mooseman]

What Wooluf meant was that if you put the shifter in 2nd when you take off, it will take off in second, not first. It will be a dog and use more fuel. The owners manual explains this as to use in slippery conditions.

 

[dkvasnicka]

What Wooluf meant was that if you put the shifter in 2nd when you take off, it will take off in second, not first. It will be a dog and use more fuel. The owners manual explains this as to use in slippery conditions.

Interesting! I never noticed that in the manual. Now that I look at it it says "You can also use SECOND (2) for starting the vehicle from a stop on slippery road surfaces.", which is a kind of indirect hint at what you're saying But I get it.
Saab 9-5 has a "W" button for this and since I found no button in the 9-7X I simply thought this feature is not there. Very glad to know. The 4.2 has plenty of torque to be able to get the car moving on ice and/or snow when needed.
Is this a common "convention" on US vehicles in general?

 

[Sparky]

I think it is mostly common. My 99 Camaro won't start in 2nd if I put the shifter there, it still starts in 1st then shifts to 2nd, but there is a "SGS" switch on the dash for "second gear start" - well, was, I never drive this one in the winter so I removed the switch and used the switch spot for something else I put in its place.

 

[AtlWrk]

It cant shift to fourth with the shifter in 3rd.... As i describeed, I am putting it in third or otherwise it shifts to fourth just like I and you state.

This doesn't apply to the OPs specific case but from the hydraulic schematic manual for Overdrive Range (4th gear):
"Under normal operating conditions the converter clutch is not applied in Third gear. How-ever, at heavy throttle positions and vehicle speeds above approximately 105km/h (65 mph), the PCM will command TCC apply in Third gear."

 

[Harpo]

This doesn't apply to the OPs specific case but from the hydraulic schematic manual for Overdrive Range (4th gear):
"Under normal operating conditions the converter clutch is not applied in Third gear. How-ever, at heavy throttle positions and vehicle speeds above approximately 105km/h (65 mph), the PCM will command TCC apply in Third gear."

That's interesting, does it say anything how the tranny is "thinking" in pos 3?.

 

[Mooseman]

OK, to clarify things, lets do a chart as to what happens at each gear selection, AFAIK:

1: Stays in 1st gear, no TCC lockup
2: Starts and stays in 2nd gear, no TCC lockup
3: Starts in 1st gear, upshifts to 2nd and 3rd normally, TCC lockup in 3rd while cruising/light load
OD: Starts in 1st gear, upshifts to 2nd, 3rd and 4th normally, TCC lockup in 4th while cruising/light load. No TCC lockup in 3rd.

 

[MikeHayes]

Ok I have to ask the dumb, noob question.... What is TCC Lockup?

 

[Wooluf1952]

Torque Converter Clutch (TCC)

 

[l008com]

I drive around in 3rd gear when I'm running a tank of gas that has Seafoam in it. I like to make sure I get the RPMs way up to thoroughly clean everything. Terrible for gas though. Even worse on my 5.3.
But reading the first post, it sounds like @OP is just feeling the responsiveness that comes with being in a much lower gear than you need. Like when you put a manual in 3rd on the highway. You're wasting tons of gas but if you just look at the gas pedal, see ya later!

 

[gmcman]

I use 3rd quite a bit in the city, especially when I know my speeds won't reach 50 MPH. Also after installing the TCC PWM eliminator, keeping it from going into 4th and lugging around at 1500 RPM is easier on the motor.

 

[l008com]

My motor loves 1500 rpm