81 monte chifts only at high rpm..help

[my81montecarlo]

81 with a 283 and 200r4,transmission will only shift above 4500 rpm.downshift cable is not connected.and transmission dont slip when shifting and when the cable is hooked up is down shifts.what will cause the transmission to shift at high rpm??

 

[pontiacgp]

That's not a downshift cable ...that is the TV cable has to be installed and adjusted correctly or you'll damage the transmission..

http://www.tciauto.com/Products/Instruc ... adjust.htm