Hard Shifting 4L80E

[charp1824]

I just replaced my rear main seal and obviously you have to remove the transmission. After I got everything back together, I drove it around and noticed it shifts hard now. When I put it into gear it spits and sputters and eventually will die and it idles perfect. Never had any problems before shifted great and ran great. it seams shifting into 4th gear is smooth and normal but not the other gears. What could it be? Something electrical?

 

04 GMC 2500HD 6.0L 4L80E

[davester]

maybe check for codes from the tcm?  This takes a more advanced code reader than the regular cheap ODBII code readers.

 

But also maybe unplug/replug the electric connectors, and check that the shift cable is properly attached.