My 1993 GMC shifts way too early and will not downshift unless I do it

[happypackfan]

manually. In 4wd it shifts ok 4 a time. My 1993 GMC shifts way too early and will not downshift unless I do it manually. In 4wd it shifts ok until its warmed up. My transmission is I believe a 700r4. This is boggling my mind. Please help!! Fluid has been changed along with filter, but other than that I am stumped.

 

[Pedro S]

tranny is shifted by compuiter... can be affected by bad battery/bad bat connection...bad tune up [believe it] get to good mechanic

 

[Pedro S]

tranny is shifted by compuiter... can be affected by bad battery/bad bat connection...bad tune up [believe it] get to good mechanic