90 toggle switch front axle (i think)

[Joe91M]

so I've been going through my '90 Z71 with a fine tooth comb lately as i wait for parts to build my 93. Among other issues that I've come across, the 4 wheel drive wasn't working correctly, and the front drive shaft is completely worn out. The PO told me it would only lock up for him with a fuse in the fuse block and that you had to pull the fuse to take it out of four wheel drive. Sooo, I've been doing some digging and swapping of parts. so far, i have come across a bad set of U-joints, a slip yoke that has a full 1/4 inch of lateral play in it, an unplugged t-case switch, an unrelated but also unplugged backup light switch, a set of lights that were flip flopped in the shifter assembly for the t-case, a leaky set of axle seals, and a slower leak on my pinion shaft. the worst thing i found though, was that the two wires to the t-case for the 4wd switch were stripped back at the plug and twisted together for a positive full time engagement of the front axle. Separating these got rid of my 70 mph drive line vibration from spinning a bad drives shaft for no reason.

My current plan is to find a new drive shaft for the front end, replace my rear u-joints, and then wire in a toggle switch to engage my front axle so that i can still have 2 lo for moving stuff around my yard and for crawling in traffic. ( there is a security checkpoint in my morning commute that is usually at least a mile long crawl and i just had ankle surgery.) my other option

 

[Joe91M]

So I've looked at it some more, and I've decided that I should be able to run the actuator and the sensor and retain the indicator light in the shifter housing without any issues. My only concerns now are where to put the switch and whether or not to run a relay. Also contemplating switching to the stepper motor. I guess I need to check out the schematics for how the stepper motor receives power.

 

[Fordum]

Not sure which system you have. But, if its the old heater type, there may still be another option. The first units did not use a stepper motor, they used a sealed cylinder with a low boiling point fluid and a heater.
To engage the axle, you put 12v to the heater. It boiled the fluid and the pressure extended a pushrod that did the engaging.

Some of the problems with that were the obvious, burned out heater, fluid leak. Plus slow engaging in real cold weather and the axle disengaging when you turned the truck off.
Which meant that you had to wait a few seconds after cranking it back up.

Warn made an aftermarket replacement that did away with all that. It was an adapter that replaced the module in the axle and let you run a mechanical cable from the dash.
I helped install a couple, and both of my friends liked them. If I remember, the only problem I had with them was that due to the geometry of the adapter, you would push in the knob to engage the axle and pull it out to disengage it.
Which meant that you normally drove around with the knob pulled out. Unlike most pull knob controls.

But it definitely eliminated axle shifting problems.

Somebody told me they had quit making them, but I'm not sure. You might still be able to find some in stock somewhere. I also do not know which years it would fit.

Just something to think about.

 

[Fordum]

OK, looks like someone is still making the unit. I swear I thought Warn made it, and maybe they did. But this company seems to be making it now, and it looks like they fixed my main complaint.
According to the instructions, now you pull it out to engage the front axle.

http://4x4posi-lok.com/index.html

 

[Joe91M]

I've seen those but honestly, I have the the new heater element style that was $40 or so vs the $120-200 for the pull cable engagement. Also I'm just kinda curious to see if I can make it work. I will update on whether it works or not tomorrow, and if not I will probably end up just going with the pull type. My only real concern is weather or not I need a relay to run it. The circuit has a 25 amp fuse in from the factory. I will have to see if I can find the warn version though. I have only seen some cheaper looking versions. I appreciate the info on that.

 

[Joe91M]

Got the switch and relay in place. Now I've gotta go through the wiring for the axle and try to tie in the sensor and the indicator light on the shifter and wire the actuator to the relay. I will try to remember to take a picture of what my harness looks like for everything tomorrow.

 

[Joe91M]

Got the switch and relay in place. Now I've gotta go through the wiring for the axle and try to tie in the sensor and the indicator light on the shifter and wire the actuator to the relay. I will try to remember to take a picture of what my harness looks like for everything tomorrow.