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-   -   4 Wheel Drive & 4 low light (https://www.ranger-forums.com/drivetrain-tech-37/4-wheel-drive-4-low-light-1576/)

RuggerNate 09-06-2004 01:16 PM

Alright, did a little wheeling last night, nothing major. Again, my dash lights are still on. Before it was just a pain, now my speedo is messed up too. Apparently the computer still thinks I'm in 4 Low. So when I'm driving in 2 HI, around 55mph, the spedo reads around 30....... Cralwed underneath and cleaned up the contacts, still no change. Any other suggestions or ideas? Last time I took it to the dealer and they said all problems were due to escessive mud and water. What to do??????? Oh, it's a manual transfer case, not the dial..

FireRanger 09-06-2004 02:54 PM

I got a Fabtech Light bar
The speed is not determined like that. That wouldn't be the problem. Something else is screwing up the speed sensor. What, I have no idea. But the speed is real-time, not a guess based on RPM.

RuggerNate 09-06-2004 09:32 PM

Tonight when I left my paretns the lights were out. The speedo and odometer are also working correctly now....... Don't know how to explain it, but as long as it's working, I'm happy!

FireRanger 09-07-2004 03:43 AM

Sometimes it's better to just accept that it is working and pretend nothing happened.....

DownSouthTAS 09-07-2004 05:45 AM

The VSS is in the rear differential.

To go along with the computer thinking you are in 4Lo, what were your RPMs at 55mph, even though the speedometer was only reading 30mph or so?

LILBLUE04FX4L2 09-07-2004 07:18 AM

Try a 20 minute plus battery disconnect, and inspect the VSS connections above the rear pumpkin.

Dave and Julie 09-07-2004 09:23 AM

I have the same problem. The switches that tell the PCM where the transfer case lever is are screwed up. It's on my long list of things to repair before the warranty is up. The VSS doesn't know what speed you are travelling at, it just counts revolutions. The truck calculates actual speed for display on the dash based on some factors, like tire size, axle ratio and transfer case gear selection. If it thinks you are in 4lo it will reduce the speed displayed by 2.48 times, but if you really aren't in 4lo you'll be going 2.48 times faster than the speedo says.

FireRanger 09-07-2004 09:32 AM

I don't think the computer re-calcualtes the speed based on anything like that. If the speed is measured in rear diff, there is no reason to re-calc anything. It is uneffected back there, the speed it's turning is the speed you are going.

Dave and Julie 09-07-2004 11:01 AM

Then how do you explain my speedometer reading 30mph with the 4lo indicator lit, when I am really in 2hi travelling at 50mph?

Tire size and axle ratio are stored values entered into the module during programming. The VSS does not know what these values are, it has no clue what size tires you have or what axle ratio you have or what range you have selected in the transfer case. All it does is go "blip" on each revolution of the axle. The speedometer can only display the actual speed by taking the blips and calculating the speed through the parameters provided by the other modules involved.

FireRanger 09-07-2004 12:22 PM

Yes, but the gearing before the rear diff has no bearing on it. The rear diff turns the same number of times per wheel revolution regardless of the gear you are in. Of course it has to be calibrated for the size of the tires, but I can't fathom what the transfer case gearing has to do with it when the speed measurment is taken in a device that is not effected by it's change.

Dave and Julie 09-07-2004 12:59 PM

It is true that the rear axle turns a certain number of times at a given speed regardless of what the rest of the drivetrain is doing.

But what is not true is that the signal from the rear axle tells the speed of the truck to the insturment cluster module. It has to calculate it based on those parameters I discussed before.

What you say would make things nice and easy, if it just read the speed of the rear axle and displayed it. It is probably one of those things that just got out of hand. It could have been made simple, but then someone thought to put tire size in there to make it easier to calibrate for different models and then it went downhill...

In fact, what if the IC gets the speed from a different source, say the transmission output shaft or something else. Since I am curious, and I have access to Ford engineers, I will go find out the truth.

Dave and Julie 09-07-2004 01:40 PM

OK, here is the deal. The Ranger rear axle speed sensor is only for the ABS system and is not linked to the insturment cluster or PCM. In the case of the manual transmission, vehicle speed is determined from the OSS, output shaft speed sensor, on the transmission. From there it is subjected to the calculations previously mentioned and then a speed is displayed by the speedometer.

FireRanger 09-07-2004 01:50 PM

What about an automatic?

Dave and Julie 09-07-2004 01:55 PM

ISS, intermediate shaft speed, still on the transmission.

FireRanger 09-07-2004 02:10 PM

Well, now that makes a little more sense. I can see where that would need the calculations involving T-Case gearing.

NHBubba_Revisited 09-08-2004 10:44 AM

Oh ho ho! I had this EXACT same problem just last winter w/ my '03 FX4. The problem is a defective swtich on the manual t-case lever. It took me nearly 6 mo to convince my dealer that the problem existed because the vehicle works fine once the driveline is warm. When the vehicle is cold the switch malfunctions and 'sticks' in 4Hi or 4Lo. Now this doesn't matter much since we have a manual t-case. The truck is in whatever position you have the lever in, regardless of what the idiot lights say. The downside is as you've found out, if the switch thinks the truck is in low-range it will incorrectly show your speed.

I use 4Hi a lot more than I do 4Lo, so I rarely had this problem. I mostly lived w/ the 4Hi indicator being on when the truck was in 2Hi as an inconvenence. Eventually I had the truck at the dealer overnight for the crappy clutch to be repaired (don't get me started) and they 'discovered' the problem the next morning when they started the truck cold (and I strongly suggested that they give it a try). It was a 10 min fix and probably cost them like $30 to do it. Sadly in typical dealer fasion then would not do the work until they could reproduce the problem!

There was a guy on the old gen-edge that worked at a dealer. He knew of the problem, had it on his truck, and swapped out the switch himself. He took a picture of the underside of the t-case and pointed out the switch housing. I'm not sure if you can still search the old gen-edge, but there was a whole discussion about it.

The next problem you'll have, if you're as 'lucky' as I am, is w/ the linkage on the t-case lever. Apparently the original design used some rubber grommets to connect the parts of the linkage. Shortly after I got my switch fixed my t-case linkage jammed and I was unable to access any x4 modes. I was rip-shit and brought it back to the dealer. He talked me down and ordered new parts. Apparently there is a TSB out about this and the fix is to use plastic grommets instead.

It's been several months now since I've had problems w/ the driveline in this truck, thank gawd. But needless to say I don't trust the stupid thing all that well. The ironic part is that the manual t-case is a big selling point for the LII package, as it is supposedly much more reliable than the electronic shift. Sadly my experience has been nearly the opposite. While this is my first 4x4, 2 of my 4 major problems w/ this truck have been t-case related. Overall I'm not impressed. I'll probably look Toyota next time, unless I go back to cars.. ..Best of luck w/ your setup. I feel your pain!

Dave and Julie 09-08-2004 10:56 AM

My transfer case has always worked. If I had to pick between working indicators and working shifter I would take the shifter every time.

I've even had an inbetween verson of this problem, no speedo at all. not sure how I did that one.

NHBubba_Revisited 09-08-2004 12:24 PM


Originally Posted by Dave and Julie
My transfer case has always worked. If I had to pick between working indicators and working shifter I would take the shifter every time.

Agreed. But for $20k of my hard earned dollars I want and expect it all to friggin' work! Call me silly, but I expect a brand new truck to work perfectly..

Dave and Julie 09-08-2004 12:25 PM

That is the one thing that is not an option with these trucks, trouble free service.

NHBubba_Revisited 09-08-2004 01:12 PM

Ha! Yeah. Sucks I had to find out the hard way..

LILBLUE04FX4L2 09-09-2004 12:02 AM


Originally Posted by NHBubba
Ha! Yeah. Sucks I had to find out the hard way..

LIL BLUE has provided trouble free service, even after I floated and then sank her.... 8)

NHBubba_Revisited 09-09-2004 07:40 AM

I dunno what to say really. While I've never 'sunk' my truck, towed an oversized load, or abused it off (or on) road, I did have to visit my dealer no less than 8 times in the first 9 months of ownership! Doesn't sound right to me.. ..If your experience is otherwise, count yourself as fortunate..

Dave and Julie 09-09-2004 08:18 AM

I stopped counting trips to the dealer.

FireRanger 09-09-2004 08:54 AM

Knock on wood, but I am at almost 34,000 miles and haven't had a single problem yet. I hasn't done any hardcore off-roading but I am anything but nice to it going to rescue calls. I'm sure at 36,000.01 my engine wil explode.

RuggerNate 09-09-2004 04:52 PM

Well I had this most recent problem. And am now at 25,ooo miles. Then before that I took it in for the same issue, major squeak in the springs (again) and a throttle position sensor problem. Dealer said all complaints were due to excess mud and water and would be monitored in the future. Ok, it says "Offroad" right on the side, but I take it offroad, and gets a little dirty then all these problems happen? Ok, maybe more then just a "little" dirty.... But I think I should be able to take it offroad without the rear springs driving me nutz!!!!
Also had the master and slave clutch changed out, rear shock leaked and replaced at 4,700 miles.... Also had the TSB on transfer case done with the bushings replaced at the same time. Then drive shaft "clunk" fixed at 20,000 miles. Oh, and I drove over a bolt and had it removed from the tire......
Overall, it's a great little truck when it's running good and not in the shop..

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