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Discussion Starter · #1 ·
I have a 1994 Trooper with the 5 speed and the 3.2L GM engine that seems to have had the speedometer and odometer go out. So, my first step was to track down where the speed sensor was on the vehicle and take a look at it. Well, gee whiz, what do you know, the PO had taken copper wire and tried to tie the sensor back together when the plastic housing came apart into 2 pieces. Okay, that obviously had to be the problem, right? So I went and replaced the sucker for $100 off of Rockauto and installed it. Still no speedo. Cleaned it with MAF cleaner and the plug in. Still no speedo or odometer. Everything else in the cluster works fine. So my next step was to try to trace the wires from the sensor back to see if it was something else up the pipe. Everything looked all good and connected and, at least on these wires, not spliced together anywhere. I continued the search underneath the dash and attempted to get my hand up there behind the cluster to no avail. Above that metal crossbar everything mounts to, I can't fit my hand due to the plastic and such for the bottom part of the cluster and other plasticy stuff. Now, I had the speedo come on for a half second once after making a U-turn and the trip odometer tries to read something, but can't read anything over 1/10 of a mile before stopping. I've reset it several times over a good 15-20 mile distance and the same thing keeps happening. Does anyone know of any tricks or tips on getting the cluster out of the dash without ruining the wood trim on it? Or even better, if there's something I'm missing that doesn't involve that much work? Haha.
 

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88sport said:
I have a 1994 Trooper with the 5 speed and the 3.2L GM engine that seems to have had the speedometer and odometer go out. So, my first step was to track down where the speed sensor was on the vehicle and take a look at it. Well, gee whiz, what do you know, the PO had taken copper wire and tried to tie the sensor back together when the plastic housing came apart into 2 pieces. Okay, that obviously had to be the problem, right? So I went and replaced the sucker for $100 off of Rockauto and installed it. Still no speedo. Cleaned it with MAF cleaner and the plug in. Still no speedo or odometer. Everything else in the cluster works fine. So my next step was to try to trace the wires from the sensor back to see if it was something else up the pipe. Everything looked all good and connected and, at least on these wires, not spliced together anywhere. I continued the search underneath the dash and attempted to get my hand up there behind the cluster to no avail. Above that metal crossbar everything mounts to, I can't fit my hand due to the plastic and such for the bottom part of the cluster and other plasticy stuff. Now, I had the speedo come on for a half second once after making a U-turn and the trip odometer tries to read something, but can't read anything over 1/10 of a mile before stopping. I've reset it several times over a good 15-20 mile distance and the same thing keeps happening. Does anyone know of any tricks or tips on getting the cluster out of the dash without ruining the wood trim on it? Or even better, if there's something I'm missing that doesn't involve that much work? Haha.
HAVE YOU REMOVED AND CHECKED THE SPEEDO DRIVE GEAR THAT DRIVES THE SPEED O SENSOR , VERY COMMON AT HI MILEAGE FOR THE TEETH TO SHEAR OFF .

AND BY THE WAY THAT IS NOT A GM ENG , IT IS AN ISUZU ENG, 100%
 

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Discussion Starter · #3 ·
I haven't done that yet. I have to assume that I have to remove the cluster to do that though right? What is the least damaging way to do that?.
 

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88sport said:
I haven't done that yet. I have to assume that I have to remove the cluster to do that though right? What is the least damaging way to do that?.
NO NO, THE SPEED SENSOR IS MOUNTED ON THE RT REAR CORNER OF THE TRAN S FER CASE , UNPLUG THE SPEED SENSOR HARNESS AND REMOVE ONE BOLT HOLDING IT TO THE T/CASE AND PULL THE SENSOR AND COLLAR OUT AND TAKE A LOOK AT THE DRIVEN GEAR . AND SEE IF IT LOOKS WORN OUT OR MISSING TEETH.NORMALLY IF THAT GEAR IS STRIPPED YOU WILL GET NO SPEEDO OR ODOMETER READING AND A CHECK ENG LITE
 

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Discussion Starter · #5 ·
Oh, okay, you're talking about that. Okay, I will remove it and see. I had it off once to take the copper wire off of the plug that screws onto the outside of the metal part that the PO had put on. I just have to make sure to have a catch pan underneath it to catch all of the oil coming out of the transfer case. For some reason it didn't occur to me the last time that there might be fluid in there haha.
 

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88sport said:
Oh, okay, you're talking about that. Okay, I will remove it and see. I had it off once to take the copper wire off of the plug that screws onto the outside of the metal part that the PO had put on. I just have to make sure to have a catch pan underneath it to catch all of the oil coming out of the transfer case. For some reason it didn't occur to me the last time that there might be fluid in there haha.
JACK THE BACK END UP ABOUT A FT HIGHER THAN THE FRT END AND THEN REMOVE THE COLLAR AND SPEED SENSOR , AND YOU WILL PROB NOT LOOSE ANY FLUID. ALL SO CHECK WHERE THE SPEED SENSOR SCREWS ONTO THE GEAR COLLAR , SOME OF THOSE MODELS HAD A VERY SHORT DRIVE SHAFT IN BETWEEN THE SENSOR AND THE END OF THE GEAR RIGHT WHERE THE SENSOR SCREWS ON , IF THAT LITTLE SHAFT IS MISSING THE SPEED O WILL NOT WORK.
 

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IMG_20150415_132409341.jpg
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So here's the speedo gear. Appears to be no wear on the nylon gear, it spins with a slight bit of resistance like it should, the shaft is in there, and it all looks kosher to me. I put it back in and the speedo blipped once like it did before and the trip meter tried to read it for a bit, but I still have nothing. Could it be the gauges? Anyone heard of that being an issue for a 1994? I know in the Chilton manual it said that that was the first place to look in an older Trooper, but it was the late 80's ones.
 

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88sport said:
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So here's the speedo gear. Appears to be no wear on the nylon gear, it spins with a slight bit of resistance like it should, the shaft is in there, and it all looks kosher to me. I put it back in and the speedo blipped once like it did before and the trip meter tried to read it for a bit, but I still have nothing. Could it be the gauges? Anyone heard of that being an issue for a 1994? I know in the Chilton manual it said that that was the first place to look in an older Trooper, but it was the late 80's ones.
OK THAT GEAR , LOOKS FINE, ARE YOU GETTING A CHECK ENG LAMP ON , AT ANY TIME, IF SO, THE SPEED SENSOR MAY BE BAD AND THAT WOULD STOP THE SPEEDO FROM WORKING , IF NO CHECK ENG LITE THE SPEED /SEN IS WORKING , GOOD POSSIBILITY THE SPEEDO HEAD HAS GONE OUT ON YOU . SINCE IT ITS TOTALLY ELECTRONIC
 

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Discussion Starter · #9 ·
Yeah I am getting a check engine light on, but I replaced the speed sensor already once, so would it still be that?
 

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88sport said:
Yeah I am getting a check engine light on, but I replaced the speed sensor already once, so would it still be that?
COULD STILL BE THE SPEED S ENSOR OR THE WIRING , YOU NEED TO PULL A CODE FROM THE ECM AND SEE WHAT IT TELL YOU. IF IT IS A SPEED SEN PROB YOU WILL GET A CODE FOR ONE .
 

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Discussion Starter · #11 ·
Okay, but the light only comes on when I am coasting it in gear, particularly in 5th gear. other than that, it wont really come on for anything else.
 

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Discussion Starter · #12 ·
So, with my latest adventure as part of this saga, I went and took the dash apart to get to the speedometer and it seems that all of the wiring to it, the plugs, and all that jazz are good with no breaks, disconnects, corrosion, half-done wiring, nothing. I'm really wondering where the problem has to be now.

Please correct me if I am wrong, but if the speedo gear in the transfer case is nylon, and it seems to spin relatively easily, wouldn't that mean that it has to be operated by the motion of the fluid in the transfer case? I can't find anything in the manual I have about how it works; just how to replace it.
 

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88sport said:
So, with my latest adventure as part of this saga, I went and took the dash apart to get to the speedometer and it seems that all of the wiring to it, the plugs, and all that jazz are good with no breaks, disconnects, corrosion, half-done wiring, nothing. I'm really wondering where the problem has to be now.

Please correct me if I am wrong, but if the speedo gear in the transfer case is nylon, and it seems to spin relatively easily, wouldn't that mean that it has to be operated by the motion of the fluid in the transfer case? I can't find anything in the manual I have about how it works; just how to replace it.
IF THE TEETH ARE NOT MISSING ON THE SPEEDO DRIVE GEAR AND YOU ARE NOT GETTNGN A CEL, ABOUT THE ONLY THING LEFT IS THE DRIVE MOTOR FOR THE SPEEDO, AND THEY DO GO OUT AFTER MANY YEARS, THE DRIVEN GEAR IS PLASTIC AND IS DRIVEN BY THE OUT PUT SHAFT IN THE TRANS FER CASE .
 

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Discussion Starter · #14 ·
So in essence, I will have to take apart the transfer case in order to diagnose what is really going on in there?
 

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88sport said:
So in essence, I will have to take apart the transfer case in order to diagnose what is really going on in there?
NOT VERY LIKELY ANYTHING WRONG IN THE T/CASE, PULL THE SPEED SENSOR OUT AND TAKE A FLASH LITE AND LOOK INTO THE HOLE WHERE IT GOES , AND TAKE A LOOK AT THE DRIVE GEAR , NOW ROTATE THE DRIVE SHAFT SLOWLY WHILE WATCHING THE GEAR , IF IT IS TURNING THERE IS NO PROBLEM INSIDE . SHOULD BE A STEEL DRIVE GEAR .
 

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Discussion Starter · #16 ·
Okay, I'm going to cange the oil again tomorrow because it was so filthy after ~200 miles last time so I will look while I'm under there. I'll see if I can get you pics, but from the angle it's at, that will be a challenge.
 

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Did this ever get solved? Having the same problem.
 

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Did this ever get solved? Having the same problem.
I'd pull the VSS (Vehicle Speed Sensor) as per Jerry's recommendations above. It's the part most commonly at fault when you have a no-speed/odo problem with a Gen II rig.

Rockauto.com carries those, at $95+. Found one for $7.92 shipped on ebay, can't beat that!


Here's some info on testing a VSS that may help:

 
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