93 2nd into 3rd gear problems

[krodriguez]

I have a 93 Suburban 4L60E transmission. Its giving me code 28 which say it is the Transmission gear pressure switch, signal-circuit malfunction. I also have code 43 which is the knock sensor code.

I have replaced the 1-2 Shift solenoid the 2-3 shift solenoid the TPS and the Pressure Control solenoid.

my truck goes fine and switches into 2nd gear and then hits 35-40 and will not go into 3rd gear.

I can manually do from 1st to 2nd and then when I go into D or OD the RPMs go redline.

I pulled up a diagram of what is under my transmission pan and it shows 2 TCC solenoids a 3-2 control solenoid and a Transmission Fluid Pressure Manual valve position switch.

Is the code 28 that transmission fluid pressure Manual valve position switch?

if not what else is there that I should look for?

 

[zora]

the code calls it a Transmission Range Pressure switch. I would look at a second source to confirm what you are looking at is the same switch,

 

[krodriguez]

Thank you. I was hoping to fix it myself but since there are so many things and solenoids I don't want to chance it so it is going into the shop tonight. A lot of people have told me the transmission is blown but I don't want to even think about that now. There is only 63,000 miles on the tranny a new one was put in summer of 2003. And it all of a sudden started while I was driving on the highway.