1990 suburban v2500. The 4wd auto hubs will not disengage. Have tried shifting in and out of 4wd and going in reverse to disengage. Does not work.

Check the linkages something is not allowing you to disengage the transfer case. Try shifting it again and back up. Some of these need to disengage in reverse. Make sure you start this process with it in neutral.

is it a 4l80e electronic shift transmission....it may be an issue with the solenoid pack...you can take it to someone who has a scanner tool for the trans...if it is indeed a 4l80e

you can go to any auto store just make sure you bring the vin # with you and the year

1990 Buick REATTA Recall ID from NHTSA: 90V164000 Auto Recall Date: 09/06/1990
Vehicle Component: POWER TRAIN:AUTOMATIC TRANSMISSION:LEVER AND LINKAGE:FLOOR SHIFT
Estimated Vehicles Affected: 63964
1990 BUICK REATTA Defect Summary:
TRANSAXLE SHIFT CONTROL CABLE MAY DISENGAGE FROM THE FROM THE FLOOR SHIFT CONTROL WITH LOSS OF GEAR INDICATOR REFERENCE AND SHIFT SELECTOR OPERATION.
Defect Consequence:
DRIVER WOULD NOT BE ABLE TO DETERMINE ACTUAL GEARPOSITION THE TRANSAXLE IS IN, WHICH COULD RESULT IN UNEXPECTED VEHICLE MOVEMENTAND AN ACCIDENT WITHOUT PRIOR WARNING.
Remedy:
INSTALL A TRANSAXLE SHIFT CONTROL CABLE RETAINING CLIP TO PREVENT CABLE DISENGAGEMENT.
Notes: GENERAL MOTORS CORP., 1990 Buick REATTA Recall ID from NHTSA: 91V158000 Auto Recall Date: 09/13/1991
Vehicle Component: SERVICE BRAKES, HYDRAULIC:SWITCHES:BRAKE WARNING
Estimated Vehicles Affected: 18904
1990 BUICK REATTA Defect Summary:
BRAKE INDICATOR LIGHT MAY NOT LIGHT WHEN IGNITION IS IN THE "ON" POSITION, THE PARKING BRAKE IS APPLIED, AND THE SHIFT SELECTOR IS IN THE PARK OR NEUTRAL GEAR RANGE.
Defect Consequence:
VEHICLES WOULD NOT MEET THE REQUIREMENTS OF FMVSS 101AND 105.
Remedy:
REPLACE THE PROM IN THE BODY COMPUTER MODULE TO PREVENT THIS CONDITION FROM OCCURRING.
Notes: GENERAL MOTORS CORP., 1990 Buick REATTA Recall ID from NHTSA: 90V031000 Auto Recall Date: 02/12/1990
Vehicle Component: AIR BAGS:FRONTAL:SENSOR/CONTROL MODULE
Estimated Vehicles Affected: 857
1990 BUICK REATTA Defect Summary:
THE FORWARD SENSOR FOR THE AIR BAG MAY HAVE BEEN INCORRECTLY CONSTRUCTED WITH PART OF THE WIRING HARNESS TO THE SENSOR REVERSED.
Defect Consequence:
THE REVERSAL OF THE WIRES COULD CAUSE DELAY IN THE DEPLOYMENT OF THE AIR BAG AND INCREASE THE SEVERITY OF THE OF INJURY TO AN UNBELTED DRIVER IN AN ACCIDENT.
Remedy:
REPLACE FORWARD DISCRIMINATING SENSOR AS NECESSARY.
Notes: GENERAL MOTORS CORP.

drive in reverse for 20 feet. if that doesn't work try disconnecting the battery neg first for a couple min hit your 2wd button.

try reversing for about 5 metres after disengaging.this used to work on my old toyota.

are you remembering to unlock your hubs ???

You might want to check the gear selector switch that is located on the driver side of the tranny, if the 4x4 is electric and not manual for engagement, selector must read neutral to disengage 4 wheel drive. by experience if you drove it through deep water gear selector switch can get damaged.
Your hubs may be locked as well. Try reversing for 30 or more feet to try manually unlocking your hubs. Make sure 4WD is turned off when trying.

No unless the auto locking hubs disengage the 4 wheel drive system stays in, our patrol sometimes disengages in forward motion but more often than not we have to reverse. hope this helps

As far as I know the procedure should go something like this...

Stop the vehicle, engage the parking brake and if applicable, get out and turn the hubs on the front wheels from Free, to Lock.(You may not have these on a Suzuki, they may be auto-lockers)

Get back in the vehicle and put the transmission shift selector into Neutral.

If you have a manual transfer case, move the selector-shaft to 4x4-High, or 4x4-Low -- whichever is desired. Now, putting the vehicle in gear with the transfer case is sometimes somewhat difficult. As long as the vehicle's transmission is in neutral, don't worry, the gears inside the transfer case are big and beefy -- Don't be afraid to be rough -- Again as long as the transmission is in neutral. You may also have to disengage the parking brake and slightly let the vehicle roll forward or back with your foot-brake to get the Transfer case to lock into place.

Once 4x4 of the selected High, Or Low range is selected, usually indicated by the vehicle jerking slightly with a slightly loud clank/thud. Move the Transmission selector out of neutral into your desired gear (Drive if Automatic, if Manual, whichever gear you pull out from). and voila! You should now be in 4-Wheel-Drive.

To disengage 4-Wheel-Drive. Just reverse the steps.