03 2500HD 4wd issue (arg)

[tribaltrans]

All, New to this group, not to wrenching or 4x4's gas or diesel. any info welcome..

Spent a good 2 hours or so searching, no conclusive answer.

2003 2500HD Diesel 4x4

Can an ABS error prevent all new hard parts to not engage 4wd? Driving or parked..

also have brake indicator as well as the dreaded "Service 4wd" error.

NEW Encoder, New Dash switch, New front axle actuator, Fluids checked and changed

Batteries detached for over 30 minutes

The Instrument panel rebuilt and all gauges and fuses in operating condition.

I have been able to get 4lo and back to 2wd (some effort) never 4hi without light flashing and falling back to 2wd. rolling & parked, in neutral and drive tested.

Speed sensor?

Ill be putting on jack stands tomorrow to ease any binding and check grounds again (1st thing I checked).

Truck was purchased knowing 4x4 was inop. Has temperature control issues and cabin fan speed problems. Parts in hand, 4x4 more important.
Runs incredible, pulls in 2wd like a beast..220k miles.

Thanks,
Tribal

 

[Awenta]

Put a tech 2 on it instead of replacing everything

Sent from my SM-N910V using Tapatalk

 

[tribaltrans]

Parts were included..thanks

 

[chevyburnout1]

Run by the dealer and have them pull all the codes in the whole vehicle. That'll help us greatly. Could have been a wiring problem the whole time.

 

[02CCSB]

ABS error won't prevent shifting.

Long story short, unit likely has mechanical failure inside, mode fork the culprit.