I have case Steiger 450. It is showing Trans fault 05042. Any idea what it is?

Any fault codes showing in memory when you read the codes.

sounds like you may have way over filled your tranny fluid.

Run fault codes and look for a TCM fault as it controls the shifting on the transmission.

most likely a thrush washer is at fault since the 4x4 kicks in for you
Have a trans shop give you an idea how much to repair before you grind this thrust washer to bits

i have a 99 durange and it wont go into part or reverse and the shop said it was a trans ring. 450 dollars

need to get trans checked by knowledgeable machanic,maybe its not engaging because the selector isnt working,big money if incorrect diagnosis,but does need to be looked at by expert

in the safety switch on side of transmission

i think u may have blown a fuse

It sounds like the trans has gone into "Limp In" mode. You may need to access the trans controller and look at fault codes. A Generic OBDII scanner may give you the codes. You could also try disconnecting the battery which will reset the trans controller. (however that is not a cure but it will verify the trans was in fault mode) The most common issues I've seen have been with the "Input" and "Output" Turbine Speed Sensors. They are both mounted on the trans case (External). The input is towards the front and the output is near the rear.

The information I can find on this shows a code 15, not 16. It shows it as a problem with the #1 shift solenoid or it's harness. Causing different internal transmission concerns. The book I found shows no code 16,this could be a miss print. Either way, this is a concern that appears to be an internal trans. problem.Good luck.