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Username Post: 99 k1500 not locking in hi 4x4        (Topic#358800)
93 low 
Poster
Posts: 73

Loc: So Cal
Reg: 12-06-11
11-12-19 06:57 PM - Post#2780077    

99 k1500, 5.7 vortec, auto trans, extended cab, GMT 400. Has the electric push button switch on the dash for the 4x4. 2HI & 4x4 low work fine, but doesn't lock into 4x4 hi.
Manual says when shifting from 2HI to 4HI, press and release the 4HI switch. This can be done at any speed, and the front axle will lock automatically with some delay.
Any idea how long of a delay?
Thanks



 
rockfangd 
"6th Year" Gold Supporting Member
Posts: 2778
rockfangd
Age: 33
Loc: Utica ny
Reg: 04-13-10
11-14-19 06:18 PM - Post#2780176    
    In response to 93 low

Delay should not be long.
You need to find out if the transfer case motor is at least trying to turn it.
It takes longer to go into 4lo than 4hi.
It sounds odd that 4lo works but not hi.
Has the transfer case motor been replaced yet?

Old School GM fan FOREVER


 
93 low 
Poster
Posts: 73

Loc: So Cal
Reg: 12-06-11
11-14-19 09:04 PM - Post#2780193    
    In response to rockfangd

Delay should not be long...>> I drove it for a few miles today in 4hi and no change.

You need to find out if the transfer case motor is at least trying to turn it...>> How would I check that?

It sounds odd that 4lo works but not hi...>> It locks in to 4lo in less than 2 seconds.

Has the transfer case motor been replaced yet?..>> Not that I know of.

What does the transfer case motor do? Does it shift the transfer case from hi to lo or lo to hi?

I used to have a 76 K20, 4x4, SB 350, SM465 w/ a 205 transfer case & I know all about those, but this is new to me.
Thanks again



 
rockfangd 
"6th Year" Gold Supporting Member
Posts: 2778
rockfangd
Age: 33
Loc: Utica ny
Reg: 04-13-10
11-15-19 07:34 PM - Post#2780261    
    In response to 93 low

I honestly like my 90.
It has manual transfer case lever. I put the case in the range I want.
The motor turns the shaft on the TC to the correct range.
Go from 2hi to 4hi and have someone listen to see if they can hear any noise from the transfer case. No noise at all I would suspect wither a wire issue or bad motor.
If it does make noise but does not go in I would suspect a faulty motor

Old School GM fan FOREVER


 
454cid 
Valued Contributor
Posts: 3129

Age: 46
Loc: West Michigan
Reg: 02-18-12
11-17-19 02:56 AM - Post#2780338    
    In response to 93 low

  • 93 low Said:
99 k1500, 5.7 vortec, auto trans, extended cab, GMT 400. Has the electric push button switch on the dash for the 4x4. 2HI & 4x4 low work fine, but doesn't lock into 4x4 hi.
Manual says when shifting from 2HI to 4HI, press and release the 4HI switch. This can be done at any speed, and the front axle will lock automatically with some delay.
Any idea how long of a delay?
Thanks



Are you sure 4-lo is actually engaging the front axle and not just the low gears in the transfercase?

99 K3500 RCLB


 
JeremyB 
Senior Member
Posts: 753

Reg: 10-31-01
11-19-19 01:59 PM - Post#2780537    
    In response to 454cid

Doesn't the light on the switch keep blinking until the axle actuator is engaged?
It might be an encoder issue, see https://www.gmtruckclub.com/forum/threads/2hi-4lo -...



 
93 low 
Poster
Posts: 73

Loc: So Cal
Reg: 12-06-11
11-26-19 04:16 PM - Post#2781024    
    In response to rockfangd

It turns out the transfer case encoder motor was the problem.

Thank you everybody for all your help.



 
rockfangd 
"6th Year" Gold Supporting Member
Posts: 2778
rockfangd
Age: 33
Loc: Utica ny
Reg: 04-13-10
11-26-19 07:10 PM - Post#2781031    
    In response to 93 low

Excellent.
I figured that is what it would be.
Thank you for updating

Old School GM fan FOREVER


 
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