flashing indicator lights

Hello everyone.

My 96 k15 tranny is acting up. After a hard day Wheelin last week. I noticed that the [prnd321] was blinking in P,N,OD,and 2. At 1st I thought it was just bulb replacement. But this can't be, so what happens is it goes in the select gear, but the light will stay on or it will turn off. It shifts fine, goes in all gears fine. so whats the problem? I asked around and alot are saying your 4l60E is electronic it has an actuator for engaging the tranny mechanisms, shifting stuff insde as well. So they say I need the actuator. Oh! Plus my thermal 4x4 actuator is toast it goes into LOW but not HI. easy fix workin on it tdy. Then there is a cracked water pump replacing this tdy too.

Pls help with the tranny problem? THX.
One more thing what is code 1870 or is it 1860 mean?

try contacting www.sonnax.com for a lot of your questions. They have a free catalog that gives a lot of detail about code 1870 and whether it applies to you or not.

If the code happens to be the 1860, I'd check out the connector on the tranny for problems, and look at the park/neutral switch(determines the lighting of the PRNDL) It could even be the start of an ignition switch problem.

Are you replacing the front axle actuator with the electric motor type(gm part #26060073) or the thermal?

I am replacing the actuator, with an after market I saw on, 2 guys garage its a manual not electric or thermal. Name is 4x4 Posi-Lok it replaces the stock with a better design, that guarantees that the frt axle engages all the time.

As for the code it is a tranny code where, yes it is a switch problem. These new trucks are becoming more and more electric, switch, actuator and relays. Good for the grocery getters, but we wheelers know more electric more problems.