BJ74 T-case not engaging in 4 Low

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Malahki

Malahki

10 Year 15 Year
Joined
Oct 1, 2006
Threads
81
Messages
1,074
Location
Lethbridge AB
So I just had a shop rebuild my T-case in my 1989 JDM BJ74. I picked it up late friday afternoon and as soon as I got the chance to try it I noticed the 4WD light does not come on in 4Low. I put the truck up on jack stands and confirmed that their is no power going to the front drive-shaft. If I engage the vacuum shift 4Hi button on the dash then I do get power to the front drive-shaft whether in 4Low or 4Hi.

So is this a manual linkage issue? It looks and feels "normal". Any advise here? I cant talk to the shop until Monday morning and would like to know what the problem is before I do
 
theres a plug that connects onto a switch on the back of the transfer case that activates the 4wd solenoids on the firewall when the low range lever is put into 4L, have a look underneath and you'll find they haven't plugged the connector back onto the switch
 
These are the only three electrical units that I can find which are all located on the right hand side and they all are plugged in. Is it one of them you are referring too and if so which one?

photo (2).webp
 
Here's a better view of it but judging from the silicone all over the one located at the top front I am going to have to guess that's the culprit. Wires must have gotten pulled out during disassembly and they tried siliconing them back in

photo.webp
 
So I pulled the 4WD actuator switch and cleaned all the silicone off. To my surprise it looked good and the wires are completely intact and undamaged. I am not really sure why he covered it with silicone?? I guess I'll call the shop in the morning and go from there.....

On the flip side this gives me an idea to wire in a toggle switch on the dash to interrupt the connection to this 4wd actuator switch. This should allow me to have the option to run 2WD in low range which would be handy in certain situations.
 
I talked to the shop this morning. Turns out they siliconed the 4Low actuator switch because oil was leaking out of it. I also tested the switch for continuity and it is no good. Possibly due to the oil interfering with the contacts. I also used a wire to jump the terminals in the connector located on the truck and 4low engaged. So it looks like its a nice easy fix if I can find the switch. So far no luck
 
Rather than add wires down to the transfer case...
Just find the signal wire to the vac solenoid on the fire wall....And interrupt / supply voltage when you want to fool the system...
Even easier if you just want 2WD low... don't engage the hubs........
 
The advantage of adding a switch to fool the system into 2 Low over leaving the hubs unlocked is I wouldn't have to get out of the vehicle on the trail when trying to turn really sharp or when the 4WD is trying to pull me straight through a turn. My other thought is if I ever damage the front axle (shaft, birfs, hubs, ect..) I can completely disengage the front and limp off the trail in 2Low

And yes my plan is to find the wires at the firewall not the T-case.
 
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