I’ve bought an 2007 Hummer H3 recently, I’ve been wondering if it’s best to keep the gear selector in position “3” until I reach speeds above 55 mph. It seems like all that unnecessary shifting into 4th Gear (OD) and back into 3rd Gear would cause a lot of wear/tear on the trans and shorten it’s life. I’m looking to get the most miles out of the 4L60-E transmission. Thanks

 

Do you have larger than stock tires on your H3? When I had 37s (Alpha w/4.10 gears) on our H3 I would use 3rd in the city because it would hunt between 3rd and OD. Once I regeared to 4.56s I would just leave it in "D".

 

I just have the H3's standard 32" tires, but most of my driving is between 30-45. This is where it will shift into 4 Gear (OD), and I'm constantly slowing down and speeding up. Seems like all that shifting would shorten the life of the trans. Isn't it the 3-4 clutch that usually goes bad in these transmission usually?

 

More likely third gear, then second, reverse and inability to fully lock up. There really is no "fourth gear", it is actually full Torque Converter lockup which is set to happen by PCM command at appx 45MPH. No shifting, just full lockup that acts similar to an overdrive.

I have driven GM trucks with these same 4l60E trans for decades. It has a "D" for drive, use it.

Here is what your Owner's Manual states:
"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."

 

What’s the normal acceleration shift speeds for the I5 H3? To me, it sounds like it shifts 4 times getting up to 40mph. 1-2 (10-13mph), 2-3 (23-26mph), 3-4 (32-35mph), TC Lockup at (40-45mph). Is this correct or does it actually not have a 4th gear?

 

There is NO 4th gear.

The 4L60E family of transmissions use 2 shift solenoids, 1-2 Shift Solenoid & 2-3 Shift solenoid. By activating and deactivating the solenoids in a predetermined pattern by the PCM shifts 1-2 and 2-3 occur, and when the torque converter clutch is commanded by the PCM to engage and locks up, 4 distinct gear ratios can be achieved. 1st=3.059; 2nd=1.625; 3rd= 1.000 and lockup at 0.696. Reverse=2.294

2006 & 07 H3s have no Transmission Control Module so the shifts are controlled by the PCM. 2008+ H3/H3Ts all have a PCM and a TCM.

 

Interesting. I can find no reference to the 4L60E being a 3-speed + torque converter lock-up. There are 4 different possible shift solenoid positions, each one corresponding to a gear:

Not trying to argue, just looking for clarification, as I too can distinctly feel 3 shifts and I can also go in & out of lockup on the freeway easily just by slightly varying the pressure on the throttle pedal, while remaining in 4th. Everything I can find on the 4L60E trans says that it is a 4 speed transmission. 3rd gear is 1:1 ratio and 4th is an overdrive ratio of .69:1. It also has a lock-up torque converter (TCC) which is a separate function (controlled by a separate solenoid) and engages in 3rd and 4th gears under light throttle.

 

I drive my 3 in [3] >>OEM 4l60e<< [D] only used 55+.
3-4/4-3 around 45(depends on throttle%):

 

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Ok, Thanks. Seems like the 4L60E does a lot of 3-4-3-4-3-4 in the city which I would think would cause a lot of wear on a tranny. Will the engine take 2,500-2,800RPM around 50-55MPH without any noticeable engine wear or should I shift it into “D” when I’m above 2,500RPM.

 

Use FULL synthetic oil + stay below the REDLINE!

Horsepower @ rpm: 242 @ 5,600
Torque (lb-ft) @ rpm: 242 @ 4,600
Maximum engine speed (rpm): 6,300


Superior temperature resistance. Synthetics can safely handle higher operating temperatures without oxidizing (burning) or breaking down. The upper limit for most mineral-based oils is about 250 to 300 degrees F. Synthetics can take up to 450 degrees F. or higher (some as much as 700 degrees F).