TCC flutter Advice?

[r-charger]

I think I have TCC flutter. The symptoms seem to point that way (I thought it was engine issues at first).

2004 Envoy i6
No mods

Recently replaced:
Fuel pump
Fuel Filter
Variable timing cam/crank solenoid
Cam sensor
Plugs
Air filter
Cleaned throttle body
Thermostat
Temperature sensor
...all to try to resolve this problem. (I was convinced it was an engine issue)

The O2 sensors replaced 2 yrs ago
All fluid changes last summer (Transmission, Transfer case & diffs)

No codes using scan tool. (pending or otherwise)

Once the Envoy warms up (about 5 miles), holding a constant speed the engine varies by about 300 rpm giving a surging sensation. It's very rhythmic. From reading, searching and cross referencing I think it's the TCC flutter.

The more I read the more confused I get. I've read posts here, at the offroad site, and the "other" site.

I do some towing, very little offroad... mostly daily driver stuff.

I looked at the shift kit:

TransGo Engineering Solutions

Should I get the SK 4L60E or 4L60E-HD2? The writeup I read had the HD2 but got confused when I read other posts whether the HD2 is needed to fix the problem or they just wanted to further upgrade. Would it be worth it to get the HD2? Is this the kit to fix the problem?

Do I need to buy a big honk'in kit with corvette servos & stuff or will the kit from TransGo be all I need? I just want to fix the flutter but don't mind spending a bit more if it will help make the transmission more reliable/last longer. I really don't care about making the truck into a performance machine... just a reliable one.

I appreciate any advice any of you can give.

BTW, I'd prefer not taking the transmission out.

Thanks!

 

[dfc739]

The HD-2 kit includes several spring changes to make gear shifts harsher/hold longer at higher RPMs. It's typically meant for heavy towing or someone that wants to punish themselves and passengers. I didn't want that so I went with the Transgo SK 4L60E. Instructions were great. Just make sure to leave ample time.

Fixing the TCC flutter is actually super easy and I'm disgusted I was almost robbed of $500 at a transmission shop to do it. The SK 4L60E kit comes with the ISO-CONV valve, I think they call it. Others just call it the isolator valve. It removes the PWM (pulse width modulation) of the TCC lockup. Remember before how you really couldn't feel the application of TCC? That was the result of the PWM. When you remove it, you get more of another gear shift and it holds lockup better.

I wrote up an article using this kit, but it was more centered around a few other parts that are known weak links (plastic accumulators and valve body separator plate). You don't need to drop the transmission to install this kit but have a clean place that you don't mind getting transmission fluid on. There is a parts list in this other link.
http://gmtnation.com/f93/how-remove-4l60e-valve-body-replace-plastic-accumulator-pistons-4972/
http://gmtnation.com/f24/built-4l60e-replacement-4894/

Others have also done the same work and installed the corvette servo, which is NOT necessary. It's just another nice upgrade. I put my corvette servo in later.

 

[r-charger]

Thanks dfc739!

My parts all have arrived. I've read and read and read...
I think I'm ready to tackle it!

Wish me luck!
Thanks for the help!