4WD not working does not appear to be in 4WD

1990 CHEVROLET 1500
150,000 MILES • 4.3L • 6 CYL • 4WD • MANUAL
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JAECHOLSJR
  • MEMBER
  • 1 POST
Truck listed above is a K1500 WT with 4WD and floor shifter. Will go into 4 lo and work properly but light on 4 WD indicator goes out when moved to 4 hi. Does not appear to be in 4WD at this point. Will not light up when moved from 2WD to 4WD hi. Where do I need to begin looking to figure out issue?
May 2, 2021 at 7:54 AM
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JACOBANDNICKOLAS
  • ✓Experienced Mechanic
  • 110,240 POSTS
Hi,

When you shift to 4wd (hi or low), a signal is sent to the front axle actuator to engage the front wheels. SInce it works in low range, the actuator seems to be working.

Since you are not getting a light when shifting to 4wd hi, I have a feeling there is an issue with the linkage itself. It may simply be out of adjustment.

Let's start by adjusting the shift linkage for the transfer case. If you look at the two pics below, they provide directions for adjustment. Try this and let me know what you find.

Take care,

Joe

See pics below.
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May 14, 2021 at 4:20 AM
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