I will say, your vehicle has 127k miles, and the trans in your type of vehicle, including the 626 and the 6 all have trans concerns that have always been consistent. It is possible that your vehicle may need a trans, I have not looked at the vehicle, I am only going by information given. With the information given, having over 30yrs of repair experience with all makes and models, and knowing how expensive it is to replace / rebuild a trans., I recommend to you, as I have many other people to try and go the cheapest route first. It is always a gamble when a trans has the symptoms you explained, but definately the cheapest. As I said previously, flushing a trans is good, flushing a trans and changing the filter and gasket, and adding Lucas transmission fix is the best procedure. I want to ask, "has the filter and pan gasket been replaced when the flush was performed?'. Was Lucas Transmission Fix substituted for the equivelant amount of trans fluid?".
So you understand better, the transmission and its internal make-up, think of a maze (like the ones used for testing rat's intelligence, or testing our own minds), you can compare that to what's called the valve body which is on the bottom of your transmission where your filter is located. These passages are very small in diameter, and if they get sludged / varnised,and the flow and pressure's are altered, then the smooth operation of the trans is comprimised. All automatic trans depend on flow and pressure's to determine shift and gear seletion functions. Besides the flow and pressures, there are solenoids, electrical device's that operate plungers to regulate flow and or pressure's. Then you also have what is called the clutches, there are what's called band's, and some units have o-ring seal's. The best way in my opinion to describe these to you is they are very similar to the brake pad linings of your vehicle. From day one when the vehicle is new, these clutches start wearing. It is the lining wear from these clutches, metal wear from other components inside the unit, that collect in the trans filter, and that is why it is so important to replace this filter. If it is restricted completely, or even partially, it is having an adverse effect on the performance of your vehicle.
I am aware that you put out hard earned money for the flush, although, before I would call the trans a loss, I would make sure the most effort was done to keep the trans unit in service. It could be around 1700.00 up to 2400.00 to replace or rebuild.
The flush has been done per information given, if the filter and pan gasket was not replaced, I recommend having a qualified Technician replace them. After replacing them, it should take around 4.5 to 5.5 quarts of trans fluid to refill. Since the flush was performed and if done correctly, it should have all new fluid. So, go to the parts store, and purchase yourself, 5 bottles of Lucas transmission fix, and your transmission filter kit which includes the gasket (so they can't mark up the product), and have the filter and gasket replaced, and instead of refilling with trans fluid, refill with the lucas Trans Fix. You will spend in the neighborhood of 70 dollars for the parts n Lucas, and the labor is an unknown factor, hence, everybody charges different labor rates. It will be a gamble, that is a given, although in my opinion it is worth a try. feel free to ask me any questions you would like, and you can direct friend's and family to ask me ?'s also. Blessings and smiles! Stephen