[90503]

Originally Posted by hotlap

Why would they have used the non-upgraded fluid if the triple flush and TC replacement was done on my car six months after Chevy changed production? The dealer needed approval from Chevy for each step.

My understanding from Al's statement is they identified the problem as the fluid. Triple flush is to remove the old fluid from the system. If the TC was burnished due to the original fluid, the TC needs to be replace because the new friction modifier alone won't fix it

Ok....still I'm unclear on their procedures and dates....I thought that the triple flush was the first attempt (with same fluid)....then TC replacement, if needed....

After it was determined that the fluid was the problem, only a single flush with the upgraded fluid was the procedure....

I'm wondering if flushes and TC replacements were done before the upgraded fluid was put into use....If all the triple flushes, TC replacements, then "single flushes" were done with the new and improved trans fluid, then I stand corrected. Thanks.

Yeah, a re-read showed you are correct...I misunderstood the triple/single flush business...

"So, what is the service procedure? Once we determined the issue was due to the quality of the friction modifier in the fluid, we developed a service procedure to flush and fill the transmission fluid 3 times, which eliminates most of the shudder concerns. This service process may not work for a vehicle with shudder that goes too long without service, in which case it will most likely require a new torque converter. Since we started using Dexron HP transmission fluid in March of 2017 both in production and for service, we believe we have basically eliminated the shudder. When used for service, it only requires a single flush and fill.

[hotlap]

Originally Posted by cooper1965

Wow, some of you guys are really taking Al's cleverly designed response as total gospel. Im not sure if its a lack of understanding, or just plain refusal to accept the truth. So many questions UN-answered.
If there was a build date cut-off, why doesn't GM recognize it? Why weren't dealers ever informed of this information? Why does the TSB specifically list current 18's including the Camaro? Why are dealers still performing the "FIX" on 18's? If fluid was the root cause, how come there are so many examples of shudder returning? The torque converter you say? Ok, how about the guys who got the flush and a torque converter only to have shudder return again? How about the countless examples of tuner's eliminating shudder permanently? How about the fact that nothing changed fluid wise or internally in the transmissions for 2018, yet Global warranty claims are down dramatically? Ect..Ect..
You guys can believe what you want, but the proof is there. I will circle a few critical areas on my previously posted document, since there still seems to be some confusion on that subject... Once again "EOP"= End of Production.

You are missing or ignoring that Al said he changed the Camaro’s production March 2017 and was clear he was only speaking for Camaro. Meaning other models or divisions did theirs later.

[Spartan268]

I'm not completely confident in the answer but I'll take it. Worst case scenario I already accepted I should just go and get the slip values tuned out instead.

[Deakins]

The answer sounds plausible to me and I could see how a fluid spec that wasn't quite good enough could lead to the hit and miss issues. Also, I've been around a few automatic transmissions in my life (not an a8) and none of them used the torque converter in any way to regulate line pressure so I'm not seeing the slippage causing low line pressure. Maybe too much time has passed me by since tech school.

[Chutzpah]

Originally Posted by Deakins

The answer sounds plausible to me and I could see how a fluid spec that wasn't quite good enough could lead to the hit and miss issues. Also, I've been around a few automatic transmissions in my life (not an a8) and none of them used the torque converter in any way to regulate line pressure so I'm not seeing the slippage causing low line pressure. Maybe too much time has passed me by since tech school.

Not an expert either, just parroting what I've read here... Apparently, the line pressure to the torque converter is reduced under certain loads / gears. It sounds like this is done to cut down on pumping losses, which in turn increases fuel economy. Less line pressure = more slip at the converter. Add poor: fluid quality, converter material or converter machining and there seems to be a recipe for burning up the TC.

[indyz]

GM should be proactive as someone above said. If there's A date, every car built prior, should get the triple flush and TC replaced

[Chutzpah]

Originally Posted by indyz

GM should be proactive as someone above said. If there's A date, every car built prior, should get the triple flush and TC replaced

I personally appreciate the backing here... although, since I fall into that category, I'm not certain how I feel about the car being torn apart without a really solid reason (concerned about collateral damage). A free single flush and filter change, sure thing... seems to makes sense. A triple flush may be overkill. No one really knows, and for me that's the issue.

[RockerC]

Thanks for the clarification, Al. I had the flush done at 15,000 and then the TC replacement. However the shudder returned at 18,000 and has been increasingly evident. I will make an appt with dealer next week (I did not want to chance driving it during snow season).

What I don't understand is, if it got a new TC and the proper fluid, why would it be happening again? At this point it only seems to occur when in V4 mode (which, I guess would be light throttle).

thanks,


-bill

[Gunmetalmissle]

Originally Posted by RockerC

Thanks for the clarification, Al. I had the flush done at 15,000 and then the TC replacement. However the shudder returned at 18,000 and has been increasingly evident. I will make an appt with dealer next week (I did not want to chance driving it during snow season).

What I don't understand is, if it got a new TC and the proper fluid, why would it be happening again? At this point it only seems to occur when in V4 mode (which, I guess would be light throttle).

thanks,


-bill

Do you happen to have any paperwork that shows they used the latest recommended fluid?

[90503]

DEXRON® Brand Product Descriptions

DEXRON® Automatic Transmission Fluid (ATF)

Modern ATF typically contains a wide variety of chemical compounds intended to provide the required properties of a particular ATF specification. DEXRON® ATF contains the prescribed combination of additives that improve lubricating qualities for your GM Vehicle. These additives include anti-wear, rust and corrosion inhibitors, detergents, dispersants and surfactants (which protect and clean metal surfaces); viscosity modifiers, seal swell additives and agents (which extend the temperature range of the additives' application); and anti-foam additives and anti-oxidation compounds to inhibit oxidation and improve fluid stability. DEXRON® offers two varieties of ATF, Standard DEXRON®-VI and DEXRON®-HP (High Performance), used in situations where low temperature fluidity and potential fuel economy are priorities.

************************************************** *********

I found the above at GMdexron.com....http://www.gmdexron.com/overview.aspx But I could not find anything on it being for sale or available anywhere....I googled dexron hp atf, but only got info for dexron-VI for sale, but nothing for Dexron HP....just trying to find info on Dexron HP atf.....Hopefully it does exist, and dealers have been using it....just can't find it for sale anywhere....????...Maybe I'm searching wrong or something...???

[grampa_ss]

My 2016 manual says to use GM part number 19300536.
But I read on a corvette forum that that part number has been replaced with 19353429.

[Gunmetalmissle]

Originally Posted by 90503

I found the above at GMdexron.com....http://www.gmdexron.com/overview.aspx But I could not find anything on it being for sale or available anywhere....I googled dexron hp atf, but only got info for dexron-VI for sale, but nothing for Dexron HP....just trying to find info on Dexron HP atf.....Hopefully it does exist, and dealers have been using it....just can't find it for sale anywhere....????...Maybe I'm searching wrong or something...???

It’s Mobil 1 the dealers have it.

[Norm Peterson]

Originally Posted by mlee

Why would they need to say something like that.

It's a simple answer but one that pretty much sums up the issue a lot better than folks are going to get at their local dealership. It's a fluid issue not a tune issue.

Makes a lot of sense to me. Sounds a lot like the difference between putting and not putting friction modifier in when you change the fluid in a positraction axle. Or not putting in enough of it.


Norm

[indyz]

Yeah. It looks like it's pretend and extend. We do have 5 yrs 60,000 miles to get this fixed repeatedly, correct?

It makes business sense to do it this way. Such is life.