Ok,
far be it for me to interject some reason into this thread, but...
Neither side has really presented a convincing argument. One side is saying, nyah, it does. The other responds, nyah nyah, it don't.
In fact, I kind of think the people that say this is an issue has presented a slightly better case, in the fact that at least they are offering direct, anecdotal evidence of an issue.
And, until I see something from a peer - reviewed or nonbiased source, I am not completely sure that the 'new detergent' theory doesn't hold a little weight.
HOWEVER,
instead of simply arguing back and forth, I'd like to present some ideas on why you might be getting a new problem after a transmission servicing procedure. Of course, this isn't all inclusive, or necessarily correct in all instances, but its' offered here as food for thought.
improper part for application
Hey, all this stuff looks the same to me. All it has to be is a teeny bit off, right? Especially considering they routinely make changes in a model year.
checkball not in correct raceway
Wouldn't take much for this to happen. Or, maybe one gets stuck to the separator gasket, and never goes back in.
improperly installed assembly / parts
Not everything fits only one way. You think a shops' gonna admit they put your fetzer valve in backwards? (they're all ball bearing now, btw). Hell no, they're not - it was the fluids' fault. But we can fix it, credit card please....
bolt(s) not torqued to spec causing fluid blow by
I have read several places where those vb bolts have worked loose. Considering all the psi in a automatic trans system, half a crank might be just enough to kill a new install.
bolts not torqued to spec causing part warpage
Lotsa heat, right? If you can warp a 50 pound cylinder head, I guarantee you can warp anything in an automatic transmission.
air in transmission
I don't know of a way to prefill all those races and chambers. So, it might take a while to get the bubbles loose, right?
lack of prime in pump, accumulator, etc.
It could happen, right?
improperly refilled / low fluid level in transmission
Hey, if not enough goes back in...
existing part damaged during disassembly or reassembly causing new issue
For instance, maybe one pin on the electrical connector gets bent or has just enough corrosion to make an intermittent short.
operator mistaking PCM relearn cycle as new issue
On electrically controlled transmissions, whenever the keep alive memory gets cleared, like when you pull the negative (you NEVER pull the positive), the PCM needs a few cycles to relearn everything. Until it figures it out, there's going to be some harsh shifting and other similar issues.
improper prep causing premature failure of installed part
You used a wood chisel on that gasket residue again, didn't you? lol
introduction of contaminants during service causing new issue
This could be a big one. I imagine with some of the orifices I've seen, it wouldn't take a pinhead sized piece of shop lint, or maybe you dislodged something else, and bam. New owner concern. I am betting a little occlusion in the pipe to the radiator could overheat the trans, right?
unintentional adjustment of item causing new issue
Maybe you bumped a band locknut.
item reached mean time between failure point unrelated to current repair.
Everything breaks eventually. Lets say part A fails at 90,000 miles. You do a fluid change at 89,000. Part A is going to fail at 90, it doesn't matter what you did or didn't do, its' just the way it is.
There could be others, thats' all I could think of on the drive into work. Maybe there are others, but every one of those potentially could cause the same issues. Flaming and other meanness welcome.... lol
Shawn