so at 100,000 miles I'm planning to replace the transmission fluid and filter.

I'm looking at the service manual, and assume that " 6L50/6L80/6L90 " means the 6 speed transmission.

Do I seriously have to remove the cat?!?!

I bought this manual way back in 2009. Can't believe I never actually used it until now...


Service Information
2009 Chevrolet Tahoe - 4WD | Avalanche, Escalade, Suburban, Tahoe, Yukon (VIN C/K) Service Manual | Transmission | Automatic Transmission - 6L50/6L80/6L90 | Repair Instructions - On Vehicle |
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Automatic Transmission Fluid, Fluid Pan and/or Filter Replacement




Component Name

Caution: Use Dexron VI transmission fluid only. Failure to use the proper fluid may result in transmission internal damage.

Preliminary Procedures
Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle.
Disconnect and lower the catalytic converter. Refer to Catalytic Converter Replacement.
Place a suitable drain pan under the transmission.

1
Transmission Fluid Pan Bolt (Qty: 18)

Caution: Refer to Fastener Caution in the Preface section.

Tip
Tighten the bolts in the sequence shown.

Tighten
9 N·m (80 lb in)

2
Transmission Fluid Pan Assembly

Procedure
Check the condition of the draining fluid. Refer to Transmission Fluid Check.
Fill the transmission with the proper fluid. Refer to Transmission General Specifications.
Fill the transmission with the proper amount of transmission fluid. Refer to Fluid Capacity Specifications and Transmission Fluid Check.

3
Transmission Fluid Pan Gasket

Tip
The fluid pan gasket is reusable. Inspect the gasket to determine if it may be reused.

4
NEW Fluid Filter Assembly

Tip
Pull the fluid filter assembly straight out. Do not bend or twist the filter neck.

5
NEW Fluid Filter Seal Assembly

Caution: Do not damage the case sealing surface when removing the filter seal assembly.

Procedure
Use a screwdriver or snap ring pliers to remove the filter seal.
Use the DT 47848 and the J 42183 to install the filter seal.
Lubricate the filter seal with transmission fluid before installing the filter.
Special Tools
• DT 47848 Seal Installer

• J 42183 Driver Handle

© 2016 General Motors Corporation. All rights reserved.

 

4 speed trans have 2 large trans cooler lines that are separate from each other and clip into the passenger side of the trans


6speed trans use 2 smaller cooler lines that come across to the driver side and are bolted as one piece to the trans with a coupler.


with a helper, the y pipe can be pried down so the pan can be slipped forward and to the passenger side and out.
if the pan gasket is oem and wasn't leaking, clean it and reuse it. they are reusable and much better than aftermarket replacements.


100 000 is a long time between service intervals.

 

It's definitely a 6 speed. One of the reasons I bought it over a 2008 (way back in 2009)

c'mon my 1995 Tahoe went 260,000 miles without any transmission services and it still worked fine when I sold it.

it's OEM, I don't think the pan leaks, but there are some drips along the lines going to the front cooler. It drips, but the parts to fix it are way more cost than adding a quart every year.

 

I wouldn't worry about a cooler line seep either. 50% of the time the new ones leak the first time it goes to -40*C.


fluids cheap, trans rebuilding $$$. severe service interval is 60 000miles. if you do complete fluid exchanges after the new filter....you never need to drop the pan and change the filter ever. that is right from gm engineering.

 

In my 2007, I was able to use the pump in the transmission to pump the fluid out, while pouring in new fluid. It is the 4l60e though, not the 6 speed, so unsure if you can do it that way or not. If you can, you could at least do that without changing the filter.

Let me say, it was a 2 man job at some points, and I changed the filter. On mine one of the biggest issues was the shift cable bracket, which is mounted from the top in a tight location with torx head screws. I got so frustrated at one point, that I almost had it towed to the dealer, because I couldn't get the pan out with the bracket in the way, unless I dropped the exhaust which I had no intention of doing.

I ended up bending the bracket to the side and clamping it to the front driveshaft, allowing just enough clearance to get the pan out. After that, it wasn't so bad, but I was pretty nervous because the solenoids are right there and before I moved the bracket I thought I could clear them which I couldn't. And you don't want to mess those up.

In the end it was a 2 day project. If I was to do it again, I'd gladly pay the $225 or so I was quoted to have the dealer do it, and just mark some bolts to make sure they actually dropped the pan.

 

Same here, I had heard enough about the level of "difficulty' if you will, that I too chose to let the dealer do the trans servicing. If I had access to a lift then I'd have done it, but some things are just too much of a pain the ash to do on your back.... plus I am a super neat freak and won't tolerate oil stains on the drive way
I have gone as far as propping up card tables to block the wind on a breezy day when changing engine oil just to keep that last little tiny thread of oil coming out of the pan from being blown outside the edges of the catch pan. Friends and family know that if they have an oil leak of any shorts, don't park in my driveway...
It's not so much about being uptight about it (which I am) but I use the driveway as an indicator of a problem, if there is a drip on the driveway it tells me something is going on with one of the vehicles...