not shifting into overdrive when warm

[98Silveradoz71]

i have a 98 chevy silverado that when its cold it shifts into overdrive fine but when warm it wont. it showed s check engine code sayin the 3-4th silinoid is bad... has anyone ran into this here? im also new to this forum...

 

[71 cuda man]

Replace the solenoid

 

[98Silveradoz71]

Does anyone kno of a thread to help me with this? ive never been inside a trans before...