A8 Flush
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Joined: Jan 2019
Posts: 70
Likes: 27
From: San Antonio, TX
Amen brother, I've already had my TC and whole transmission replaced and now I'm getting a slight shudder at about 2,000 RPM when accelerating (normal driving not wide open) Checked with one of two dealers I've used for this tranny thing and they are telling me I have to go thru the complaint / I have a problem routine, that they can't just do it. I'm going to check with the other dealer and see what they say, but like Maxie2U said, looking at the procedure I'm sure they're going to screw something up.
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Joined: Jul 2010
Posts: 83
Likes: 56
^^^
You should have the triple flush done again - the new fluid with the blue banner bottle has lower moisture pickup (according to GM). The new TSB is all about the fluid composition difference, not just having 'fresh' fluid. And, according to GM, the previous versions of fluid WILL pick up moisture over time thus changing the friction properties that lead to the shudder.
The 'vette procedure in the 18-NA-355 is essentially the same as the first version of 16-NA-175 -- both call out the triple flush. (A fluid flush done by dealers to resolve the shudder problem within the last 6 months or so was very likely a single flush, which is not nearly as effective at clearing out old fluid as 3 successive fluid changes. The TSB '175 was changed to a single flush procedure along the way a few months ago.)
IMO, the fluid change procedure for vettes in the '355 TSB may be the easiest of them all in that document. It says - 'Drop pan - replace pan - fill - circulate fluid;; repeat;; then fill a 3rd time and do the check level procedure.
The check level procedure has not changed from what I can tell.
You should have the triple flush done again - the new fluid with the blue banner bottle has lower moisture pickup (according to GM). The new TSB is all about the fluid composition difference, not just having 'fresh' fluid. And, according to GM, the previous versions of fluid WILL pick up moisture over time thus changing the friction properties that lead to the shudder.
The 'vette procedure in the 18-NA-355 is essentially the same as the first version of 16-NA-175 -- both call out the triple flush. (A fluid flush done by dealers to resolve the shudder problem within the last 6 months or so was very likely a single flush, which is not nearly as effective at clearing out old fluid as 3 successive fluid changes. The TSB '175 was changed to a single flush procedure along the way a few months ago.)
IMO, the fluid change procedure for vettes in the '355 TSB may be the easiest of them all in that document. It says - 'Drop pan - replace pan - fill - circulate fluid;; repeat;; then fill a 3rd time and do the check level procedure.
The check level procedure has not changed from what I can tell.
Safety Car
Joined: Aug 2012
Posts: 3,960
Likes: 1,106
We complain when dealers throw parts at a car trying to fix a problem but corporate doesn't seem to be doing any better with this shudder issue after throwing multiple torque converters, different flush and fill procedures, and 3 different fluids at an issue that has been going on for 4 years now.
Le Mans Master
Joined: Aug 2015
Posts: 8,243
Likes: 4,615
From: Southwest Florida
Clearly you must have complete confidence in your dealer and can trust they will actually conduct a complete 3 flush faithfully following the instructions as called out in the bulletin. It’s a very tedious process and a lazy mechanic could easy skip steps and the number of flushes. Yes, call me skeptical.
Last edited by Maxie2U; Jan 29, 2019 at 12:23 PM.
Racer
Joined: May 2014
Posts: 318
Likes: 49
From: Mt. Juliet TN
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Burning Brakes
Joined: Jun 2015
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And when the shudder comes back again, they will introduce the quadruple flush with fluid revision #4 including Colonel Sanders 11 special herbs and spices. That should put GM only a few months and a couple of flushes away from when most of the 8L90 transmissions will have their warranty flushed away 
Next the voodoo revision TSB will be released requiring the tech to run around shaking chicken feathers and chanting the names of past GM CEOs while doing the flush.
My Z06 has been running with a Range module since i took delivery in March 2016 and it is shudder free.
Next the voodoo revision TSB will be released requiring the tech to run around shaking chicken feathers and chanting the names of past GM CEOs while doing the flush.
My Z06 has been running with a Range module since i took delivery in March 2016 and it is shudder free.
