I have a 3800sc along with a 4t65e-hd in my 88 gt. A few months back the car started shifting weird or rather not at all on the way home from work.
It seems to have stayed in 3rd gear. Reverse worked fine. I stopped and had the codes looked at and it showed p01758 P01753 and p1860.
I cleared the codes and it drove fine for several hours then as I was picking up my son I shut the car off and the cel came back on when starting and the transmission shifting issue came back. This happend this summer but I got bad sick and couldnt mess with it for several months.
Anyone have any insight with this? I cannot imagine all the solenoids would go out at once. I've checked power to the trans connector and it is getting power.
When you are in limp mode, or the PCM is unable to activate the solenoids you will only have 3rd and reverse.
What definitions are you seeing for 1753 and 1758? When I looked in the list of DTC codes for a 98 PCM (HP Tuners) I didn't see those two listed. I did find the 1860 as a TCC solenoid issue.
As far as the TCC Solenoid goes possible causes are dirt in it, the solenoid is bad, or perhaps the internal wiring harness.
But only having 3rd and reverse is completely normal for being in limp mode. When I converted from a Muncie to the 4t65e-HD I did all the wiring correctly, but forgot to provide power to the solenoids.... I didn't get any codes, but had the same issue 3rd and reverse only.
With all three popping a code at the same time I would hazard a guess that its electrical. If the fuse is fine for them, then most likely its the wiring, unfortunately its probably the wiring inside the transmission.
I would check the external connections first though. You could check the impedance of the wires from the solenoids ( on the connector for the transmission )to the PCM connector first to see if they all check out.
If so you might have to look at replacing in internal transmission harness.