Electric t case problems

fordornothing · Feb 25, 2013

Well I'm having a problem with my electric t case. When iI Bought the pickup I never had 4 low, then today it wouldn't go in to 4 high. I tried several times and it's a no go... I looked at the wiring and the plug on the bottom end and it all looks good. Does anyone know of a quick fix for this? I plan on swapping it for a manual shift t case soon.

20007.3L · Feb 25, 2013

Replace the motor?

JLDickmon · Feb 25, 2013

replace the relays

rfrostick · Feb 26, 2013

i was having same issue with my truck, swap the relays, unplug bot plugs on t case motor and check for corrosion and plug them back in real good until you hear it snap into place, another thought im not sure if it affects it any but if you still have the vacuum lines hooked up check for leaks or just do what i did and unplug lines from vacuum pump and plug hole on pump and do away with auto locking hubs. you will have alot less problems by removing all vacuum still for 4wd. If im not mistaken the hubs will try and engauge several times and if they fail to engauge using vacuum then wont go into 4wd at all

GreenF350 · Feb 26, 2013

rfrostick said:
i was having same issue with my truck, swap the relays, unplug bot plugs on t case motor and check for corrosion and plug them back in real good until you hear it snap into place, another thought im not sure if it affects it any but if you still have the vacuum lines hooked up check for leaks or just do what i did and unplug lines from vacuum pump and plug hole on pump and do away with auto locking hubs. you will have alot less problems by removing all vacuum still for 4wd. If im not mistaken the hubs will try and engauge several times and if they fail to engauge using vacuum then wont go into 4wd at all

That last part is incorrect. It will apply vacuum to the hubs and if they are faulty/leaking/etc it may not engage the front wheels, but the T-case will still go into 4wd and give you the light on the dash, the hubs just won't "lock in".

To the OP. Are you having issues with the front tires actually getting power or are you not getting the light on the dash? These are potentially two different areas to look at and we could give better advice with that information.

JLDickmon · Feb 27, 2013

GreenF350 said:
That last part is incorrect. It will apply vacuum to the hubs and if they are faulty/leaking/etc it may not engage the front wheels, but the T-case will still go into 4wd and give you the light on the dash, the hubs just won't "lock in".

To the OP. Are you having issues with the front tires actually getting power or are you not getting the light on the dash? These are potentially two different areas to look at and we could give better advice with that information.

^^^ what he said..
and don't bother swapping cases..

CSIPSD · Feb 27, 2013

Oh hell if you can get a case cheap do it... I hate the ***ing switch on the dash. I want to be able to pull a lever back and be done.

fordornothing · Mar 8, 2013

That vacum lock deal went kaputs last winter. I just get out and lock them in. I can get the power to the ground in 4 high just no low. Which relays are they? If I get off at a decent time tomorrow I'll screw with it.
Joe- what I don't get is, it's a 6 speed. If you already have to shift just to move then what is so ***ing hard about reaching down and pulling a different lever? dam ferd engineers...

Christof13T · Mar 12, 2013

Relays are under the hood right next to brake master cylinder.
If you have towing package then its normally the 2 frthest forward.

Ignition on, engine off... in park with foot on brake... operate switch to 4x4 low.
Do you hear it try to engage?

jaybuller · Mar 12, 2013

if you get out check the bottom plug on the t-case actuator. unplug it. and if theres oil built up in it dump it out, clean it with electrical cleaner and plug it back in. then try again.

CSIPSD · Mar 12, 2013

Love being able to grab the lever and pull back... oh look, the 4x4 works. Would work underwater, would work unplugged, would work no matter what.

If I wanted a fancy button to get my truck into 4x4, I would own a GMC.

fordornothing · Mar 13, 2013

When I bought it, that was the big thing that I was deciding on.
No, it will not even try to engage into 4 low, Hell, it won't go even when you remove the actuator, so I'm thinking a switch now. The plugs looked great with no oil or dirt in them.

JLDickmon · Mar 13, 2013

you got varying voltages out of the switch?
if you did, the switch is good.

I'm still thinking relays...

got a PowerProbe tool?

shimmy underneath the thing and hook the ground lead up to where the black wire was, shoot power to the other terminal.. you should hear the motor operate

if you want, I can upload a wiring diagram when I get home..