This the Big One ! 🎈
The Hummer H2 was produced between 2003 - 2009, so now many of them have over 100K miles on the clock.
Auto transmissions are very complex systems, with many moving parts. Transmission fluid lubricates and prevents overheating, but burnt-out or old contaminated fluid, choked filters, leaky seals, metal fragments and microscopic debris can cause irreversible damage.
We do of course, regularly check the transmission fluid levels, but as you'll see there is a little more to it than just the "level"
Start by watching this video, then by doing the work yourself you can save money in the long run, save your transmission and you'll have the satisfaction of knowing the work has been done properly.
On the subject of "flushing" here's a quote from GM Service Bulletin 04-06-01-029J "It should be noted that analyses of returned parts that have been exposed to these aftermarket 'flushes' show indications of potential damage and shortened durability shortened durability"
--- Click on Timeline Marker to Skip to Segment --
00:00 - Introduction
00:49 - Technical Data
01:03 - Introduction to the 12V Oil Pump and Pan with drain plug
02:16 - Reading Dip Stick and Checking Fluid Condition
03:49 - Adding Sea Foam before draining
04:11 - Tools & Parts needed
05:55 - Preparation, vehicle on ramps, penetration oil heat shield bolts
06:31 - Pump out as much fluid as possible to reduce pan oil content
08:00 - Remove tubular Skid-Frame
08:23 - Removing fluid-pan blots
10:15 - Attempt to remove fluid-pan, the remove exhaust
10:34 - Fluid-pan out transmission exposed
10:47 - Old fluid-pan inspection and new comparison to new pan
11:31 - Partial fluid measurement
12:02 - Filter removal
12:26 - Completed fluid measurement
12:45 - Inspect Transmission flange mating surface and clean
14:33 - Removing the old filter seal - watch this segment to save time!
16:00 - Fitting the New Seal - watch this segment to save time!
19:05 - Fit the new fluid filter
20:28 - Fitting the new gasket and pan, bolt tightening patter and torque settings
22:15 - Old fluid filter inspection and new pan leak checks, heat shield and exhaust re-fit
24:48 - Transmission fluid fill
25:37 - Achieving optimum fluid purity