i have an 89xj that i use mainly for mud and sand. i sometimes use it to drive around. my jeep doesnt want to shiift by itselff. i have already put in another tcu but still the same. i also put in another tps and adjusted it and checke the voltage. i hot wired the tcu and shift manually from 1 2 3 put once i turn of solonoids 1 and 2 i dont get 4th gear. i heard sombody saying that engine has to be at operating tem for it to be able to shift to overdrive is this true.
sol 1 ON Sol 2 OFF 1st gear
sol 1 On Sol 2 On 2nd gear
sol 1 off Sol 2 on 3rd gear
sol 1 off Sol 2 off 4th gear.
sol 1 ON Sol 2 OFF 1st gear
sol 1 On Sol 2 On 2nd gear
sol 1 off Sol 2 on 3rd gear
sol 1 off Sol 2 off 4th gear.