Is my 4WD working???

[C Jeff]

I have a 95 with control trac 4WD which means when in 4HI the front wheels only engage when the rear wheels spin. The funny thing is when I switch into 4HI in about 1 to 2 minutes the lights, 4HI & 4LO, blink 6 times and go completely off, but the EX feels like it is locked in 4WD. Moving the switch does nothing to either put it back into 2WD nor does it turn the 4WD light back on. The reason I believe it is locked in 4WD is the rear wheels do not spin on wet pavement and I can feel the front wheels drag if I turn sharply. However I can get it back into 2WD when I stop put it into park and shut it off. It also does the same thing in 4LO. As a side note it did the same thing several months ago just minutes before my transmission went out. I also run the transfer case once a month in both 4HI and 4Lo to keep everything working. I am confused as to what I need to do.

 

[tenikiwon]

Don't know if I have an answer but....

Check your lights again. Do they blick six times and then go off for a long period of time and then blick on again? My 97 does that when I pull the fuse or disconnect the "yellow wire"(see other post) Mine has auto/4/4Lo and my dinconnecting the system I get the blinking lights and the 4wd system is no longer active. sounds like yours might be backwards and when you flip the switch (which might be bad) it's cause a the system to lockout and stay in 4x4.

Do you have to restart to get back into 2WD?

What does your switch look like? 2/4/4lo ?

Does 4lo work?

 

[topo4u2]

Hello, for what its worth I had the blinking light syndrome and the dealer changed my dash switched to fix it. I was surprised. It could also be your speed sensors in transfer case, this was the next option.

 

[dogfriend]

Originally posted by topo4u2
Hello, for what its worth I had the blinking light syndrome and the dealer changed my dash switched to fix it. I was surprised. It could also be your speed sensors in transfer case, this was the next option.

Did you test the switch? I still have a hard time believing that the switch was causing your problem because the front disconnect was working.

C Jeff: The flashing light is indicating that the GEM which controls the transfer case functions is detecting a malfunction. It is probably setting a DTC (diagnostic trouble code) which can be retrived with a scan tool (with GEM scan capability). The trouble code will give you a better idea of what the problem is.

If you want to try to fix it before spending money to have it scanned, I would check the connector near the transfer case shift motor to make sure it is plugged in and all wiring looks ok. Another thing you could try is to remove the driveshaft speed sensors from the case and make sure they are clean. I read here that someone else was able to fix a problem by cleaning them.

 

[topo4u2]

Hi DF. no I did not test the switch...not sure how? But they did give me the old one, and yes I have a hard time believing it myself, by the way last night I tested out the 4x4, still hate the control trac system but anyway, crawled under again and now the front shaft coming out of the case free-wheels in 2wd like it should I suppose. Weird!
Heading out to auto store for some good synthetic 5/30. Changing oil tomorrow.

 

[dogfriend]

Use an ohmmeter to test the two center terminals of the switch. I posted the values for the 97 switch in the original thread. Your values may be slightly different, but switches usually fail badly, i.e. the resistance won't be a little off, it will probably be way off (short or open) if the switch is bad.

If it fixed your problem, great, but I'm having a hard time understanding how it could be the switch when the front disconnect was working.

 

[topo4u2]

I will give it a test DF, by the way I changed the oil in my X a few minutes ago and the rear speed sensor was leaking a bit of oil so I pulled her out to fix the gasket and I noticed that there was some gunk on it. Those goof balls at the dealer never did change it like they said. I do all my own work from now, as long as I can do it..screw the warranty...see you get no warranty coverage if you do it yourself(backyard tech's) That is why I went to the dealer to begin with...NO More!

 

[dogfriend]

My rear driveshaft speed sensor was leaking at one point too. If you still have a problem, you might need to replace the o-ring on the sensor. I wasn't able to find the same kind of o-ring and ended up replacing the sensor to get an o-ring that wouldn't leak.

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also, if you ever need to replace the sensor, this might be useful:
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[topo4u2]

Thanks DF again, yes I put some high heat silcone, not very much around the seal and it works great...no more leak.
I took a drive this afternoon for some testing..here
is what happened.
I got on some sand and flipped the switch to 4 auto and got the back wheels spinning. For some reason I could not get the front wheels to spin? I even tried in 4low. Those rear wheels I feel were going fast enough to engage the front. Anyway when I got home I jacked her up and made sure that the front diff, transfer case were all locking up...they were. I'm thinking, and I do not want this to be the case after all the hell I have been through that maybe the clutches are worn in the transfer case and when torque is applied they slip?
Also since I spun the rear wheels now every time I take off from a stop I feel a little grabbing in the rear end for a couple of seconds...is that the rear end clutches in the limited slip?
And DF, I tested that switch and I can only get a reading of 5 on the 1k scale.

 

[dogfriend]

Originally posted by topo4u2
I'm thinking, and I do not want this to be the case after all the hell I have been through that maybe the clutches are worn in the transfer case and when torque is applied they slip?
Also since I spun the rear wheels now every time I take off from a stop I feel a little grabbing in the rear end for a couple of seconds...is that the rear end clutches in the limited slip?
And DF, I tested that switch and I can only get a reading of 5 on the 1k scale.

I'm also thinking that I could be a possibility, but I'm not sure how you could test to make sure that the clutch wasn't slipping. In 4wd Auto, the clutch only engages about 4% of the torque most of the time, so (even) on dry pavement its not very noticeable. Even on slippery surfaces, the system can increase and decrease the torque in miliseconds, so its hard to get the clutch to engage for very long in Auto mode.

In 4wd Low, the torque is split ~50/50 so it should be easier to tell if the clutch is slipping. Also, if you are on dry dirt with 4wd Low, and you make sharp turns, you will feel the driveline "wind up" as the front wheels move at a different speed then the rear ones. When this happens, you will feel the wheel(s) slip to release the "wind up". If you don't get this feeling, then it is possible that the clutch in the transfer case is slipping.

I had limited slip on my Ranger and sometimes it would "chatter", usually when taking off in a turn. There is an additive that you can add to the differential oil that helps to minimize / prevent this. Also, I have seen some threads on here about rebuilding the clutch pack in the limited slip. You might see if you recognize the symptoms that they discuss in the thread(s).

If it is reading 5k ohms, no matter which position it is in, then the switch is hosed.

I wonder how the front disconnect knew to engage then? Telepathy?

 

[topo4u2]

I just sent a reply but the page screwed up..I hope it does not go again..
Yes, I guess that switch is toast!
Tomorrow I'm going to jack this unit up and see if I can get all four wheel to spin. I'm also going to pull off the shift motor and check out the front sensor but I dont think it is a problem because I'm sure I would have flashing dash lights.
By the way, when I was under her today and the shaft was freewheeling, I grabbed it and gave it a back and forth spin as fast as I could, it slowly started to lock up just from the syntrical force..so maybe the clutches are grabbing but not holding when torque is applied....that would really tick me off. If that is the case its going to be a 2wd winter for me.

 

[C Jeff]

Sorry for not replying this weekend, I was at the inlaws nailing plywood on a second story house addition, I did some more driving tests and discovered that it only stays locked in 4WD when I go from 4LO back to either auto 4WD or even 2WD. Where are the sensors at and how hard are they to get out and clean or replace? Is there anyhting else I should be looking at?

 

[topo4u2]

Hi C Jeff, yippee another 95 owner!
The rear speed sensor is very easy to get at..at the rear of case..5 min job to remove an clean. The front one is behind the shift motor which must come out to get at....I would clean the shift motor while it is off if you can..there are some good threads on how to do it.

 

[topo4u2]

I am going to use this post for a question since I have used up alot of time on other ones.
Anyway, I guess my 4x4 is working ok, I put it in 4low and made some very slow tight turns and I could feel it grab somewhat so I will leave that for now. BUT, That driveshaft between case and front diff is still spinning when my dash switch is in 2wd. To my way of thinking I really dont think that is right.....so here is my question. Does anyone think that I can install a quick disconnect on that brown wire? If its power thats getting to the transfer case when it shouldn't then that would cure it and when I wanted 4 wheel I could just reconnect it. I wonder if I would get a trouble code with that wire cut?
Anyone got any ideas??
Thanks.

 

[mikefox]

topo4u2 ? on oil change...

When you posted you were going to get "good synthetic 5/30. Changing oil tomorrow" did you mean for the transfer case? If so, I think you need to check the owner's manual. I know mine says to use Mercon type tranny fluid in the T/C. This could be why you are not able to get the front to spin. Just a thought.

 

[dogfriend]

Originally posted by topo4u2
. BUT, That driveshaft between case and front diff is still spinning when my dash switch is in 2wd. To my way of thinking I really dont think that is right.....so here is my question. Does anyone think that I can install a quick disconnect on that brown wire? If its power thats getting to the transfer case when it shouldn't then that would cure it and when I wanted 4 wheel I could just reconnect it. I wonder if I would get a trouble code with that wire cut?
Anyone got any ideas??
Thanks.

Hey, I got your email. I hope that the shop working on your brakes isn't the same one that did your transfer case!

Anyway, I think that the driveshaft rotating with one of the front wheels might be normal for your truck. From the description on the other thread, the vacuum disconnect works by disconnecting the front differential from one of the front axles. The other side stays connected all of the time and spins the front shaft. Also, in 2wd, the power to the transfer case clutch should be cutoff anyway, so disconnecting the brown wire makes no difference.

You won't get a trouble code by disconnecting the brown wire, but you will if you disconnect the yellow wire coming from the GEM.

Do you have any schematics for your year truck? I have schematics of the electrical system for Control Trac but for 97 which is slightly different than your 95. I'm curious how the vacuum disconnect is turned on and off. I assumed earlier that the GEM controls it, but I don't understand how it worked when your switch was messed up.

 

[topo4u2]

Ok, thanks for the replies,
Firstly, Mike Fox- No I did not put 5/30 in case it went into engine. but thanks for checking.
Hey DF, glad you got my mail, you must think Im a pain by now. You had me thinking when you mentioned about the one side of the front diff still engaged but that theory cannot work because several time now I have been able to turn that shaft by hand with the vehicle on the ground. So if the drivers side front axle was still locked up with that rear shaft I would never be able to freely spin it, correct?
It seem that I have an interrmittant problem, like one day it will spin and the next it wont.....please keep in mind that my dash switch is still in the 2wd mode.
I believe that once you move the switch from 2wd to 4 auto it sends a signal to the gem and it sends a signal to the vacuum solenoid. I may have some diagrams available but not sure how much they will help....but I will look.
I still may dissconnect that brown wire for fun and see what happens...maybe just maybe the gem is sending unwanted power there in 2wd and causing the clutches to grab. Or the damm clutches are grabbing on there own?

 

[dogfriend]

Read this reply from the other thread:

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I don't understand/believe that the axles are spinning in different directions, but I think that he is right about the drivers side axle always being connected to the front differential.

 

[topo4u2]

Well I think Darren is right but I have to sit and think about this for a bit. It still does not explain how I am able to turn that front shaft easily in park and 2wd at times. I must be just turning the spider gears in the front differential.
Im thinking that the front vacuum solenoid would have to be engaged for there to be any torque involved with the front axle. I dont know...its crazy! What a puzzle or Iam just too damm tired.

 

[topo4u2]

I do know one thing, this is in two wheel drive of course.....if I jack up the left front tire, I can spin it no problem, and the same goes for the right front tire. That is supposed to be like that.
I wonder if I can pull a fuse temporarily and see if it stops that axle from turning.....sorry DF for turning this into a nightmare!