No i havent scanned my car for codes yet i posted mileage in the previous question from soft ride

I do a pan drop/filter change and use GM'* latest fluid Dexron VI (6) every 50 k miles.
You may want to get the codes read & see what codes state.
New fresh filter & fluid may help, but codes are needed for sure.

thank you

my 08 buick lacrosse is in the shop and the only code that is coming up is p0128 which is coolant temp below thermostat so what do i do now because there isnt any transmission codes

What kind of shop did you take it to? A transmission shop, dealer or general mechanic or ?
I find it unusual with these kind of shifting issues, that no transmission codes are present on an 08 lacrosse. What kind of scanner are they using?
What is the "shop" saying about your trans condition?

Your P0128 code- thermostat could be stuck open and only use the correct GM/ Delco replacement in there.

i took it to aamco they said they might have to run more tests but it might not be a transmission issue

If it'* not the trans hopefully they find the problem and report back what they do find.
Post back once you here more please..

The shop could not find any other codes for the Lacrosse and they said that I would need a new transmission.

How exactly did they arrive or jump to that conclusion?
Did they drop the pan, look inside for clutch material or even consider servicing the trans first with new fluid & filter and see if it runs then?
In most situations a trans can be re-built.
I am leaning towards recommending another trans shop.
What scanner were they using? It requires a good scanner like TechII or Snap on ultra to get the car scanned properly.

Attention TechII -help...
If I remember right, they should also be able to command trans solenoids to make sure they are working correctly, with the correct scanners.