Shifting from Drive to 4 and back

Hey TacomaWorld Community when I first got my truck and would drive up a steep hill or an incline, I would shift from "D" to 4 and would feel some power behind it then accelerate and make it up the hill with no problem and once I level out, I would shift back to "D". Lately, I've been noticing when I do drive up a hill and shift, I don't notice a difference shifting from "D" to 4 and back to "D." It feels like i'm in "D"rive the whole drive up the hill.

My Tacoma:
2008 Double cab 4x4
got it at 27xxx miles, currently at 31xxx miles.
The front differential and ECU was recently replaced under warranty 2 1/2 weeks ago. I did install a Magnaflow exhaust and an AFE intake back in May but I don't believe that would be the issue.

Has anyone experience the symptoms that I'm describing? Any insight, advice or suggestion is greatly appreciated.

 

Does your 4wd dash light come on and stay on??

If you're engaged in 4WD, the dash light will be on and stay on. If its blinking or not on, then you're not in 4WD.

 

I don't think he is in 4wd at all...

 

Ya, hes talking about down shifting from Drive to 4th. Is this happening at highway speeds? Because i have noticed that around town my truck stays in 4th, thus not changing anything if i were to down shift.

 

@Chachie Yeah, this is just normal driving. I stay in "D" for most of my driving and shift to "4" on some hills or if there is a slight incline. Is your normal driving in "4"?

@Janster I'm not in 4x

I really appreciate the help.

 

No im usually in drive, but this is the first auto i have ever had and have got into the habit of counting gears. So i know that around town my truck never gets into 5th gear.

 

About how fast are you going when you start the hill before you switch to 4?

 

D is all gears with overdrive (5th gear) for economy... the only time to shift down to 4 or 3 or 2 or Low is when needing to prevent the truck from speeding up WHEN you are going down a big hill... saves the brakes. But, brakes are cheaper to replace than your transmission... so be careful using your tranny to slow your truck!

 

@Dorifuto Thanks for the insight. I'll switch my driving habits and Drive in "4" for normal.

@Jason'sLawn care
I'm going about 15-20mph before I shift into "4"

 

Ummm... no, 'normal driving' use D (Drive)... Putting your truck into 4 prevents it from using 5th (overdrive) and makes your truck engine work harder than needed and uses more gas. It is an automatic, so let it do just that, shift automatically for you.

 

@David K Thanks for the correction. Too early in the morning and didn't have my cup of coffee yet....but I really appreciate everyone's insight and help.

 

That's why. You are already in fourth or in many cases 3rd going that speed so. It typically shifts into fifth at around 32mph.

 

De nada, amigo!