Having an issue with our 2007 Hummer H3. When driving and pushing down on the gas pedal when in D, will speed up to about 20 - 30 but is having a hard time increasing speed. I have to shift down to 3 to increase speed and then back to D for the increase in power. I know the H3 does not punch it when you hit the gas pedal, but we have not seen this behavior before.

Any suggestions on what this issue may be is appreciated?

Thanks
RMACH3

 

I NEVER drive in (D) unless I'm driving 50mph+ NEVER!
What are your shift points? 1-2 should be around 13-15mph normal acceleration & 2-3 should be around 22-25mph normal acceleration. Did you check transmission fluid level/condition? Could be a sticky shift solenoid? Simple to correct with Trans Tune & DEXRON-VI

 

Thanks for the input Hummerz, will review the trans fluid and possibly adding the trans tune as you suggested. Not use to shifting an automatic out of Drive, that has been our normal setting for all driving. Will update when I am done and the difference I see.

 

Whenever asking any question, include Year, Model and MILES.

How many miles since your Trans Fluid and Filter were changed?

There is absolutely no reason whatsoever to not place an auto trans in D and leave it there. They are designed to operate that way, with very limited exception, end of story.

From the OM:
"DRIVE (D): This position is for normal driving. It provides the best fuel economy for your vehicle. If you need more power for passing, and you are:
• Going less than about 35 mph (55 km/h), push your accelerator pedal about halfway down.
• Going about 35 mph (55 km/h) or more, push the accelerator all the way down.
Downshifting the transmission in slippery road conditions could result in skidding, see “Skidding” under Loss of Control on page 249.
DRIVE (D) can be used when towing a trailer. You may want to shift the transmission to THIRD (3) or, if necessary, a lower gear if the transmission shifts too often under heavy loads and/or hilly conditions.
THIRD (3): This position is also used for normal driving. However it reduces vehicle speed more than DRIVE (D) without using your brakes.
You might choose THIRD (3) instead of DRIVE (D) when driving on hilly, winding roads, when towing a trailer, so there is less shifting between gears and when going down a steep hill."

 

Been driving a 4l60e transmission for over a quarter century, NEVER had 1 fail under me!
The 4L60-E will perform better and in fact last longer if you drive using (3) instead of Overdrive (D) when you are traveling under 50 mph. Driving in overdrive will cause your transmission to shift into and out of 4th gear constantly at the lower speeds of city driving(35-45mph). Each time the transmission shifts there is slipping and friction in the clutch packs/bands. This slipping and friction generates heat, an automatic transmission's worst enemies. Plus each shift causes a minor amount of wear on the clutch and steel plates and components in the trans. After thousands of 3-4/4-3 shifts this extra wear can add up and lead to component failure.
Like shifting a manual transmission, rpm's rise 2.5k+, shift. Shifting a 4l60e driving the on ramp to the highway, rpm's rise, 2.5k+, shift! Less effort 3 to D with an automatic. I also down shift D to 3 on the off ramp.

 

Thanks Hummerz, the transmission fluid change immediately corrected the issue. Could feel a change in speed as soon as I test drove it afterwards. I am going to look at the Seafoam products for Transmission and Gas as my 07 is not a daily driver having only about $116K miles on it.

 

Currently @ 91,746 miles on my '07.#SEAFOAM WORKS SEAFOAM
I use the motor treatment in the tank, crankcase, throttle body, and induction dispenser(Starts, Runs, & Drives Like New)
I used the Trans Tune a few years back when I noticed no 1-2 shift solenoid when moving from a start, yet I could manually shift 1-2-3 and all was normal, having clean/full DexVI fluid. After a few miles with Trans Tune installed, all back to normal taking off in 3, NEVER a problem since.
Btw, my H3 has an impressive 0-60mph (when not loaded).

TopTierGas
Induction Clean: