Used t-case - cost?

[IZwack]

Since the problem is purely electrical and not mechanical, if all else fails and you're getting ready to set the vehicle on fire and walk away, you can always do the brown wire mod

 

[CASTLE95X]

Don't do that, you're gonna fry something. To reset the computer just disconnect the negative for a minute or so, let the remaining energy ground itself out through the proper grounds.

ok cool only did it once but wont do it again i already need a new tcase and front suspension thanks storlied

 

[Paraphoe]

Jason: If you remove the shift motor from the back of the t-case, but leave it connected electrically, will the motor turn when you shift between H and L?

I did this test - when I move the dash switch from high to low, nothing happens. The motor just sits there. And yet, when we hooked the motor up to a power probe, we got it to turn fine.

The motor shifts the case into and out of low gear, it does not hold the case into high or low. If you are in low, and unplug the motor, the case will stay in low (and vise-versa). You can also remove the motor and shift the case manually.

Right...I was actually initially stuck in low and removed the motor and manually shifted it to high. So now I'm stuck in high.

In addition to the GEM, there is a shift motor relay behind the dash which has a higher probability of going bad than the GEM itself.

Something to look into, but I don't think the shift motor is the issue, because as you stated earlier, it doesn't hold the truck in high, correct? From my understanding, the motor always keeps the case in the high position and a clutch actuates when slippage is detected to engage the front wheels. What detects the slipping and controls the clutch? The speed sensors?

Flashing 4wd lights could just mean dirty speed sensors (just remove, clean, re-insert) - I've dealt with that problem several times. How many times are they flashing? The speed sensor code is six flashes.

My sensors actually did have some grease spots on the front of them...should they be totally cleaned off and white? They flash 5 or 6 times. I'll try to get a better read on the number on the way home tonight.

Let me know if you need a hand with a multimeter and or the Ford electrical schematics, electrical systems are my specialty - I'll be in PA (west of Philly) this weekend.

Thanks a bunch Aaron, but I'll be at my parents in Jersey for the holiday week. But this is why this site is so great, so many people willing to give up their time and lend a hand to another guy with a problem.

Since the problem is purely electrical and not mechanical, if all else fails and you're getting ready to set the vehicle on fire and walk away, you can always do the brown wire mod

Give me a week and a few more blown vacation days and I'll be at that point.

 

[gmanpaint]

I did this test - when I move the dash switch from high to low, nothing happens. The motor just sits there. And yet, when we hooked the motor up to a power probe, we got it to turn fine.

Are you saying you supplied an alternate power source to make the shift motor turn?

That's a great way to see if it works or not...BUT....that just means your switches are not communicating with the shift motor. This is what I would be concentrating on.

Another note, those sensors need to be as clean as they can be. If your old t-case had shavings in it, they would stick to them. So YES, clean them puppies good.

 

[IZwack]

Right...I was actually initially stuck in low and removed the motor and manually shifted it to high. So now I'm stuck in high.

Thats where you are supposed to be - HI range (4wd is independent of being LO or HI) .

Dont concentrate on the shift motor - this problem isnt with the shift motor. There are only two modes for the shift motor - HI or LO. The shift motor is now where it needs to be - HI. And we've confirmed that it has nothing to do with the shift motor because Jason disconnected the connector and the vehicle stopped binding. So the problem is the electromagnet is powering up when its not supposed to.

 

[gmanpaint]

So the lack of communication to the shift motor is in NO Way interfering with the correct path of communications with the Clutch pack? To me, it all has to be in order to function correctly. One problem leads to another so to speak. The dash switches do more than control the shift motor don't they? I was under the impression that they also run through the GEM as well.

 

[Paraphoe]

Are you saying you supplied an alternate power source to make the shift motor turn?

Exactly. And it worked fine.

Another note, those sensors need to be as clean as they can be. If your old t-case had shavings in it, they would stick to them. So YES, clean them puppies good.

Yea, there was a bit of grease and some very very minor shavings. I wiped the shavings off and left some of the grease on. I will pop them back out and clean them completely as soon as I can.

 

[Andy96XLT]

In the end if you want to try a new computer I have an SOHC auto computer sitting in my garage for just such an occasion. I believe it was out of a 97, I have the vin number to check

 

[Paraphoe]

I'l let you know Andy, thanks.

By the way, if the flash pattern of the 4wd lights means anything, I confirmed on my ride home that it's the usual 6 flashes, 2 minutes apart.

 

[dogfriend]

I've never found anything in the service manual to decode the number of flashes. I believe it is just a signal that a code (or codes) have been set in the GEM. You need a scan tool with Ford Extended codes to read them. My Auterra software on the Palm Pilot can read GEM codes.

 

[V8BoatBuilder]

My money is still on the shift relay. You really just need to multimeter this one out.

1) Do you have voltage at the shift motor: If Yes, then the motor is bad, replace. If No, then go to step 2.

2) Do you have voltage going into the Relay: If Yes, Relay is Bad, replace. If No, GEM is bad.

Here's a link to a post in my 4406 conversion thread with photos of the electrical components of the 1997's shift system.

http://www.explorerforum.com/forums/showpost.php?p=1250342&postcount=205

The Shift Motor Relay is Gray, right behind the GEM. I picked one up at the Junkyard, with a TOD (for the clutch) for about $15

Here's another photo of the Shift Relay:

Photo of the Torque On Demand (Front Clutch) Relay:

 

[Paraphoe]

Thanks for the pics Aaron. I have good news. I figured I'd start checking the easy things before I started replacing parts.

I rolled back under the truck this afternoon, popped off the shift motor, and pulled out the two sensors. I cleaned off the blobs of grease that were on them that I mentioned earlier, put it all back together and took her for a spin. Problem mostly solved - now when all connectors are together, the truck is working fine in auto and 4wd high works perfectly. The flashing 4wd lights have vanished as well.

The only issue remaining now is that it won't kick into low. When I'm in high and I throw it in neutral and shift the knob to low, nothing happens (there's no clunk in the case) and the 4LO light doesn't come on either. I would suspect that that is the shift motor not doing it's job...would you guys suggest popping it out and trying to clean it out?

 

[gmanpaint]

Will it go into low if you do it by hand? If you remove the shift motor and place the rig in N, then turn the shift rail with a pair of pliers till it "Clicks" into Low. That will eliminate the clutch pack all together. I have learned in the past that just because the shift motor spins when it is off the case, it doesn't mean it is working correctly. The bushings in it might be shot, the motor too weak to turn the shift rail, etc...

 

[Paraphoe]

I'm kinda wary about messing with it at this point, but I guess I can give that a shot tomorrow.

 

[storlied]

Yeah, that's what I was saying before... the shift motor may appear to be working.. and might work for a shift that's easier to do perhaps.. but maybe it doesn't have the force to pop it into low. Glad you found the sensor malfunction though. You're pretty close to solving this issue, try replacing the shift motor and see if everything works correctly. [after checking manually]

 

[gmanpaint]

Just out of curiosity, when you tried to put into low range, did you try to drive the rig a little? Could you tell you were still in High range? Some cases will shift quietly and don't make the clunk noise at all. I am just wondering if it might have gone into low, and the dash light just didn't light up. Sorry, this was picking at my noggin not knowing..lol

 

[Paraphoe]

LOL....mine too Gregg. I didn't try driving it. I had always heard a very loud clunk in the past as it locked into low, and there was absolutely no noise when I turned the switch. Nothing changed, so I didn't even bother driving it.

 

[Paraphoe]

OK, another update. Took the motor off today. I couldn't get the shifter manually into low, and was losing patience so I said F that and left it. I had read on here that perhaps the brushes, armature, etc inside were gummed up or broken down, etc. Took the motor into the basement and completely broke it down. Everything looked fine, but I cleaned it off anyway and re-assembled it (will probably post a how-to thread on that at some point). While it was out, my father also helped me connect it to power and test the shifter. It worked exactly how it should.

So now the question still remains, what could be causing the lack of communication between the 4wd LOW switch in the cab, and the shift motor?

Aaron, your post (#71) still seems to be relevant here. Should I take these steps even with the 4wd high functioning properly now?

 

[dogfriend]

So now the question still remains, what could be causing the lack of communication between the 4wd LOW switch in the cab, and the shift motor?

Test the shift relay. The GEM reads the position of the 4wd switch (Auto, 4Hi, 4Lo) and sends a signal to the shift relay to make the switch between Hi and Lo range (or vice versa).

 

[gmanpaint]

Hmm, the fact you couldn't get it into Low by hand has me concerned. Did it feel as if there was resistance in it? Like the more you turned the harder it got to turn?

Also where you in Neutral & on flat ground? Sometimes you have to rock the rig or move it one direction to release any build up on the drive train while you move the shift rail by hand with a pair of pliers.