Hello people, I am having a problem with my 4wd. It was not working at all so I pulled my radio out and went to the GEM mod. Pulled the bottom plug out and plug it back in and it work perfect, how ever after a few days it quits working, did the same thing again and like before it worked. Has anyone seen this before? The GEM is a costly part and with my luck it might be something else, so what do you think? Thanks, Steve

 

Spray some contact cleaner in ALL the GEM connectors, also behind the GEM closer to firewall is the 4x4 Double Relay module, pull off its connector and clean it as well

The GEM is the controller but it is a low amp module
It is connected to the 4WD switch and the 4x4 relay module(electric shift control module)
When you select 4WD the GEM activates one of the relays and that sends higher amps to the shift motor on the transfer case, so it turns clockwise or counter-clockwise


And just a heads up, the shift motor can get intermittent over time, from lack of use
Good practice is to shift into 4high and then 4low and then back to 2WD at least once a month to keep shift motor brushes clean and gears inside lubed, you don't have to move the vehicle, just shift it thru the settings

 

Pulled out the double relay and un pluged it, there was corrosion on the pins and the plug, so I cleaned them up with electric cleaner. I will know in a few days if this fixed the problem, I have a good feeling that it did. The Ranger has been sitting for two years since my home burned to the ground. The truck was close to the fire so it melted all plastic including the bed liner tail lights factory fender flairs took for ever to find them. At frist the tranny was doing bad so changed filter and oil and drove it and it started shifting better. My check engine light is on with a code PO340 which is a camshaft sensor it is making a squeak noise so I took the two screws out and removed it looked ok so I cleaned it up but is still making the noise could not figure out why it was squeaking. Any thoughts on this squeak? Thanks, Steve

 

The bushing in the synchro tower, under the sensor, is worn out, need to replace that synchro tower

Both the 3.0l and 4.0l V6 engines used this synchro tower, read here: https://therangerstation.com/tech_li...nsor_cmp.shtml

The 3.0l engine was much more prone to this failure than the 4.0l, but could happen to either

There are TWO wire, and THREE wire Cam sensors, 1998 could have either so make sure you get the same one you have now

 

Hello all well I ordered a synchro tower from rock auto thought the cost would be lot more can not believe it was $35.00 for the tool an cam positioner, an tower new should get it Monday part of my birthday list took the week off plan to do alot of things to the ranger.

My next job it to line up the red shift bar it is off when you put it in park the indicator show its closer to drive an so on. Has anyone try to correct this problem? If so a few pointers would be great. Thanks for all your help on this project

 

Not to hard to adjust just some labor getting to the adjuster, lol

How-to here with pictures: https://www.therangerstation.com/for...o-trans.53854/

 

Well adjusted the shift indicator, what a piece of cake, plastic was broken so super glued it an used a wire tie to take the load off, the piece should have been made out of metal or something better than plastic. Received the Part from rock auto, look's like it is made very well, got to get it on #1 the crankshaft nut very hard to get a socket on it so I will use a big pair of channel lock to get it on number one, I guess the tool that come with it keeps the shaft in line, it kinda like installing a distributor in in a 911 Thanks all AC is next

 

well got it all done AC blows cold 4wd works camshaft tower in place i believe it is ready for that test run Thanks for all the help I received Steve

 

Good work

Thanks for the update

 

Well took ranger for test drive AC blows cold runs great however put 4WD in high than put it in low after that would not come out of low now both high an lows lights flash I am back to where I started no fuses blown, so it worked just sitting with key on you can hear it switch before, but now it does nothing, Does not make any cents to me just don't know where to look next any thoughts on this problem

 

Lights flashing mean the GEM is not seeing the shift motor move when it sends it 12v/ground

So GEM is most likely working, or no lights would flash
That leaves shift motor and Relay box, and the 2 wires between the two

Tap on the motor with hammer or ??, then see if its starts working, if so then the brushes are not aligned in the holders

 

Taped on motor no change, pulled radio out and un pluged the GEM plug at bottom of box not it works like it did before,So what do you think now ?

 

it acts like it is missing a ground wire I mean it works the way it should but take it out on the road and go in to 4wd it goes in but will not come out it just stop working unless you unplug the bottom plug on the GEM box an plug it back in have you seen this before? 423-284-1255 thanks, Steve

 

No, not a common or even uncommon situation

Out side of the motor's ground which should be on the firewall near the dual relay box behind the GEM, the rest of the system doesn't use any grounds

Wiring diagram below

The GEM sends 5volts to the dash switch, GEM gets back 3.86v and 3,870 ohms for 2wd, 2.94v and 1,090 ohms for 4wd high and 1.76v and 357 ohms for 4wd low
No ground

GEM sends 5volts to contact wheel in shift motor, and gets back 5volts on correct contact to indicate position of wheel, shift rod
No ground

Check the dual relay box ground wire

 

I saw a u 2 video where the 4wd did not work an he found a broken ground which the guy did not know where it went so he grounded it to the shift motor the wire was by itself, after he did this the 4wd worked. I looked for a wire on my truck but there was none. so what you are telling me I need a ground from the motor to the fire wall near the gem relay?

 

No, the relay box needs the Ground, motor doesn't have a local ground, or it wouldn't work, not sure what video you saw.

The shift motor needs to turn in both directions, like a power window motor, up and down
In this case left and right or counter-clockwise and clockwise
So it gets 12v/Gnd OR Gnd/12v, on its 2 wires, to spin motor in two different directions

So if you were to ground motor at transfer case it would have a fixed ground and would only be able to turn one way, like a starter motor

The Dual Relay box needs the Ground for shift motor, in diagram thats G104, it may be down at the transfer case, don't know where it is, I would think on firewall but it would make sense to ground it to transfer case or engine.

 

Hello, Cannot ground relay box it is made out of plastic, I replaced the engine in the ranger and i recall a ground wire on the fire wall, however when I put the new engine in I could not fine the ground wire which I took off, I need to find out where this ground wire goes to. Just wish I knew someone with a 3.0 ranger with 4wd. does anyone have a truck like this that can look on the fire wall to see where this ground goes, the only wire I have on fire wall is from the wiper bolt to the engine, Thanks, Steve

 

No you wouldn't ground the relay "box", the relay box has a ground wire, pin 1, a black wire, test if it is a good ground, i.e. 0 ohms to body metal, the relays inside the box use that ground for the shift motors ground

Not a 3.0l thing

All vehicles will have a ground strap from engine to firewall, this provides the ground for all cab electrics

On Ranger V6 it would be on the back of drivers side head to the firewall, wiper motor bolt was common firewall ground point, seen here: https://www.justanswer.com/uploads/m...RAGERNOISE.gif

These are straps, woven flat metal ground wires

 

hello the link for the fire wall ground does not work can you check it and resend? Thanks, Steve

 

Here is pdf of it