94 Suburban 2WD 4L60E Wont Shift Out of First until I Let Off The Gas

[Vjlaw72]

I have a 4l60e and I did a transmission flush on it and two weeks later it started the problem that I mentioned. It wont shift out of first unless i let off the gas then it shifts fine into second then third but overdrive dosent work either. Reverse works fine. I replaced the speed sensor,tps sensor and some of the shift solenoids and pan gasket and filter. There are no codes showing and I have 327000 miles on it. What could be the problem.

[j cAT]

what is the specific method you or some repair shop has done ?

you must not use any transmission flush machines on these GM transmissions !!!!!
also you do not use any Dexron III fluid.. 2006 GM has banned this ...

the proper procedure to replace the tranny fluid is drop pan clean up the mess, replace the filter .. fill the tranny with 5 qts of dexron VI.. then setup the fluid exhange method by removing the tranny cooler line top... having a clear marked container setup so fluid flows into the container .. start engine when this is all set up .. as 1 QT comes out add one quart and it may take total 11QTS of Dexron VI..to get the fluid to look like new ..

if a machine was used you will need a complete tranny breakdown and a new/cleaned torque converter .. also line/radiator tranny fluid flush ..good luck.