I am not sure if these codes are related, but a couple of weeks ago my '99 4x4 4.2L 4R70W started hesitating, in and out of overdrive, then stalling at a few stops. Got two codes, p1740 and p0742.
So I replaced the TCC solenoid and topped the fluid off (4.5 quarts). Cleared the codes and it seemed to be fine.
Now, after maybe 70-100 miles, I noticed the 4x4 light coming on, then turning off, relay click from dash and a buzzing sound from the chassis somewhere. Did this a few times.
Is there any relation between these trans codes and the 4wd? Other than GEM, I can't think of any.
I didn't disturb any external wiring to transfer case or trans.
Gem module looks dry, as a matter of fact, no rust under dash. It looks like new.
Thanks for any insight.