Miguel Olea

Thanks!!! Just what I was looking for. I wanted to reply earlier, but for some reason it was not allowing me to type and then I forgot about it. If and when they go bad, hopefully the get stuck open and I can just depin the motor wires at the main connector under the radiator close out panel and just leave the wires for the ambient temp hooked up. Thanks again. Miguel

all the mods I've seen require leaving the motor connected. I'd like to eliminate it completely. Usually it's the motor that gets water inside and then the green crusties form resulting in "lost communication" and a check engine light. I guess you could use the allen key mod and relocate the motor to an easier spot to access, but then - where would you get the stupid motor when it eventually goes bad? I just ran a bead of caulk around the top seam and put some heavy synthetic plastic/rubber safe brake caliper grease around the motor shafts to discourage water intrusion. I also added a small plastic over hang over the motor to shield it from water

well, this is getting off topic. I already have my truck back together, but any info on deleting the shutters would be great. I'm hoping to tune them out if they ever get stuck in the open position, rather than break the font end apart again to R&R them.

Because when they fail it costs $300+ for the part and requires removing the urethane bumper cap and wheel lip moldings which have numerous plastic clips and never go back the same. Also, it will set a Check engine light which will be an automatic fail at time of inspection.

morning bump - any other input?

No. The shudders are still in place. I did unbolt them and swung them over on top of the radiator support to seal the motor halves with high temp silicone. I also used some high temp synthetic brake caliper grease on the motor shafts to try and seal out water. Didn't unplug them as I was afraid to set a code. Thinking of attaching some plastic shield over the top of the motor to deflect water. Having to take the urethane bumper cap and grill off is stupid design to replace these useless things!!!

I removed the grill and upper bumper cap on my 2018 Sierra for another project. I'm starring at those stupid shudders. My truck has 47K miles and they still work. Should I replace them now as preventive maintenance? I assume they need calibration after? If they fail later, in the open position, can I just unplug them and have them completely tuned out? I've seen where people leave the motor with a stop; however, most of the time it's the motor that fails. Should I remove them clean the connections and try to seal it up? I think water enters where the shaft spins and makes its way down to the connector from the inside and gets corroded.

Bump on the thread? So much info. I have AFM turned off on my 2018 6.2. Will I loose some torque off the line if I remove this flapper valve completely? I plan on keeping the stock muffler and resonator. People who have removed the valve on a stock truck - do you notice any off the line performance loss?

I really can't say when the fluid turned cleaner as mine only had 5k miles so it was still very clean. I highly suspect GM used the wrong fluid (see above post) and that is why I changed it. I used 20 quarts to make sure it was a complete flush. Jegs had the best price with free shipping if I recall correctly. I have the thermostat delete kit in mine so it was easy to flush. One hose barb in the return port and I was good to go. I also bought an adaptor that screws into the check fill port of the pan and I was able to use a drill pump to pump the new fluid in. Shifts improved immediately after the flush. I had my doubts when doing the flush, but I guess GM did have some other fluid in that "flo tech" flush machine.

Update! I've only driven the truck 5K miles since I had the service done. My buddy and I dropped the pan changed the filter and did a flush with 20 quarts of the new blue label Mobil 1 fluid. I also added 1 10oz bottle of the lubegard platinum to further protect against any shudder although I've never had that problem. The truck drives and shifts so much better which leads me to believe that GM had THE WRONG fluid in that flush machine. It probably had Dexron 6.

I drove my brother in law's 2018 Centennial edition 2018 with the 6.2 and it is the exact same thing; so I'm more at ease. On a side note, my truck feels so much more responsive. I wonder if it is the fact that I have the catch can protecting the valves, ported throttle body, and an airaid Jr. intake. I also shimmed the plastic gas pedal bracket to take the flex out of it when you first step on the gas. Both trucks have the same ratios, engine and transmission.

I looked over the TSB and I could not find where it states that the trans needs 1,000 miles to relearn; only the 3-400 miles and to cold starts to eliminate the shudder.

right! because they said the flow tech machine was already full! So they made it sound like I got a deal and only paid for 8 quarts instead of 20. How will we ever know if it was the correct mobil 1 blue label in the machine? Of course they said "we only use that machine for 8 speed transmissions so it had the right fluid." Doubt is still in my mind.

back in November - as soon as it warms up, I'm going to drop the pan at home and replace the filter and refill with the 7.5 quarts of the new mobil 1 fluid. I will do another service after that in 5- 10K miles just to make sure the correct fluid is in the trans. So the clunky shifting for the first 1K or so miles is normal after introducing the new fluid?

yup - and that's how it all started. My 8l90 has been smooth and very trouble free. It would shift firm when driven aggressive and smooth when driven normal. I never had the shutter, but at 30K miles I wanted to change the fluid as preventative measure. I do all my own work, but b/c GM was retarded and did not include a drain bolt, dip stick or dip stick tube - I decided to have GM do the complete fluid exchange. Long story short, they made me feel like I got a deal and only charged me 400.00 dollars including 8 quarts of the new fluid. They claimed that the flow tech machine was nearly full when they started. Nearly full with what? The new blue label fluid, Dexron 6, piss, maple syrup???? Also, as I sort of watched the tech work on my truck, he did the fluid exchange before dropping the pan and changing the filter - big no, no in my book. Since then the truck was a clunky mess for the first 1,000 miles. It appears to have smoothed back out - but the doubt is still in my mind!