tforce Posted November 21, 2011 Share Posted November 21, 2011 95 Lsi Sedan AT AWD 170k'ish Speedo bounces from 0-20mph. Gonna check tomorrow and see if I have a cable or not. Started doing it this summer. Car still seemed to run/drive fine so I didn't think much about it. AWD quit working. No CEL or AT lights. Did a tail housing pull and grind gooves repair last winter to fix torque bind. Worked great all winter. Did not replace my Duty C.....oops? I thought I noticed something off about the AWD this summer on some gravel hills but I never got stuck or anything so I thought I was just imagining it. Started up my snow and ice driveway last night and had to try 3 times before I made it. I've got really good studded tires. No help at all coming from the rear wheels. Gotta get those babies back in the game. Duty C? VSS? Bad AT Temp light not telling me something is wrong? Link to comment Share on other sites More sharing options...
nipper Posted November 21, 2011 Share Posted November 21, 2011 VSS's. There are two. When one fails the other takes over and drives the spedo. Whne one fails AWD is shut down since the car has no way of telling if wheeels are spinning or not. 1995 may or may not have a cable driven spedo as that is a switch year. If it is cable then it would be a bad spedo cable and may still very well be a bad vss sensor also. Link to comment Share on other sites More sharing options...
tforce Posted November 21, 2011 Author Share Posted November 21, 2011 VSS's. There are two. When one fails the other takes over and drives the spedo. Whne one fails AWD is shut down since the car has no way of telling if wheeels are spinning or not. 1995 may or may not have a cable driven spedo as that is a switch year. If it is cable then it would be a bad spedo cable and may still very well be a bad vss sensor also. Any good way to tell which one has failed? Link to comment Share on other sites More sharing options...
nipper Posted November 21, 2011 Share Posted November 21, 2011 Is there a flashing ATF light? For some reason they do not always throw codes. Unplug one and drive. If there is no change it is that one, if there is nt its the other. Another possible scenario is that if it is cable driven the cable drive gear can be stripped and cause the same issues. First look and see if you have a cable or not. Link to comment Share on other sites More sharing options...
tforce Posted November 21, 2011 Author Share Posted November 21, 2011 Is there a flashing ATF light? For some reason they do not always throw codes. Unplug one and drive. If there is no change it is that one, if there is nt its the other. Another possible scenario is that if it is cable driven the cable drive gear can be stripped and cause the same issues. First look and see if you have a cable or not. No flashing ATF light. I'll check on the cable tomorrow and go from there. Thanks for the quick response Nipper. Too many car issues lately and I really need to focus on the house. It's reassuring that it may be a quick fix. Link to comment Share on other sites More sharing options...
nipper Posted November 21, 2011 Share Posted November 21, 2011 This usually is. Link to comment Share on other sites More sharing options...
johnceggleston Posted November 21, 2011 Share Posted November 21, 2011 usually it is the front one and that is the one that lends it self to be replaced. the rear one does not have an easy disconnect wire like the front. the hard part is getting the wrench on it. a deep well socket may be your best bet. Link to comment Share on other sites More sharing options...
tforce Posted November 21, 2011 Author Share Posted November 21, 2011 usually it is the front one and that is the one that lends it self to be replaced. the rear one does not have an easy disconnect wire like the front. the hard part is getting the wrench on it. a deep well socket may be your best bet. No speedo cable....yay! I unplugged the front sensor and the speedo didn't work at all. So, I happen to have spare tranny and am going to rob the rear speed sensor from it. If that doesn't fix it I'll be back with more questions. Any tips or cautionary words on replacing the rear sensor? Link to comment Share on other sites More sharing options...
johnceggleston Posted November 22, 2011 Share Posted November 22, 2011 Any tips or cautionary words on replacing the rear sensor? yes 2 tips, 1. there is no wire connector so you will have to splice it. B. it is not the problem, i have never heard of it failing. III. don't do it , it is not the problem. Link to comment Share on other sites More sharing options...
tforce Posted November 22, 2011 Author Share Posted November 22, 2011 yes 2 tips, 1. there is no wire connector so you will have to splice it. B. it is not the problem, i have never heard of it failing. III. don't do it , it is not the problem. Ok. You obviously have some experience with this. What do you think it is? Instrument cluster.....bad connections? Link to comment Share on other sites More sharing options...
johnceggleston Posted November 22, 2011 Share Posted November 22, 2011 bad front speed sensor. swap it out. Link to comment Share on other sites More sharing options...
tforce Posted November 22, 2011 Author Share Posted November 22, 2011 Fair enough. I've got one of those on the spare tranny too! Link to comment Share on other sites More sharing options...
tforce Posted December 5, 2011 Author Share Posted December 5, 2011 I can't seem to find the right wrench for pulling the front VSS. Crescent wrench is just going to strip it out. It's not a 17 or a 16mm, not a 5/8ths. 16.5mm maybe? Anyone have any tips on getting this thing out? Link to comment Share on other sites More sharing options...
tforce Posted December 17, 2012 Author Share Posted December 17, 2012 Didn't want to start a new thread so I'm hoping someone will pick up on this. I have swapped out both speed sensors and still have speedo bounce below 20mph.....doesn't tend to happen when the car is cold and first driven. Pan bolts were loose so some fluid had leaked out. Tightened em up, topped off fluid and things seem a little better than before. AWD seems to be decent above 30mph or so but barely there at driveway speeds. Rear left and front right wheels spun when I had the car lifted. Wandering where to go next. TCU, ECU, gauge cluster, pressure test the line to the tail housing? Just say screw it and put in a cheap tranny that I know is good? Link to comment Share on other sites More sharing options...
johnceggleston Posted December 18, 2012 Share Posted December 18, 2012 (edited) auto or manual? were the replacement parts new or used? known good? or suspected to be good? have you pulled the instrument cluster and checked the screws on the back side of the speedo to see if they are loose? Edited December 18, 2012 by johnceggleston Link to comment Share on other sites More sharing options...
WoodsWagon Posted December 19, 2012 Share Posted December 19, 2012 The front VSS feeds directly to the speedometer gauge in the cluster. The speedo gauge then translates that signal and sends it on to the engine's computer and the transmissions computer (ECU and TCU). The problem is in the speedo sensor to instrument cluster part of the system. The AWD isn't working right because the TCU is getting a bad signal from the speedometer gauge in the cluster. The rear VSS has nothing to do with the speedo, it only talks to the TCU and the TCU uses it's data internally to run the AWD. It is not used as a backup sensor to run the speedometer. The TCU compares the signal coming from the speedo gauge to the rear VSS to figure out how much slippage is happening. Loose screws that hold the speedo gauge into the cluster and also form the connection to the printed circuit board on the back are a common problem and easy to check. The speedo's themselves do fail sometimes, but it's much more rare in the 95-98's vs the 99's. The other thing to check would be the speedo sensor drive gear. You take the sensor out and put a flathead screwdriver down in and try to very gently turn the shaft. It's a plastic gear and if it wears out it can start skipping on the drive gear inside the differential housing. If you can turn that shaft without the wheels moving the gear is done. Unfortunately that means pulling the transmission and separating the front diff housing off it to get at it. Hope that this isn't your problem and check the gauge cluster first. Link to comment Share on other sites More sharing options...
tforce Posted December 20, 2012 Author Share Posted December 20, 2012 Auto. Parts are from the old tranny and worked fine before it was pulled. Haven't checked the gauge cluster but will do that next. Thanks for explaination on the speedometer system Woods. Link to comment Share on other sites More sharing options...
tforce Posted March 25, 2013 Author Share Posted March 25, 2013 Gauge cluster was fine. No loose screws. VSS isn't stripped. I'm assuming I need to replace the speedo....is there anyway to test it to make sure it's bad? Link to comment Share on other sites More sharing options...
WoodsWagon Posted March 25, 2013 Share Posted March 25, 2013 Buy a cluster from a you-pull-it junkyard for $20 and plug it in. Link to comment Share on other sites More sharing options...
tforce Posted March 31, 2013 Author Share Posted March 31, 2013 Buy a cluster from a you-pull-it junkyard for $20 and plug it in. I would love to know where you get them for $20. Most of the local yards wanted $70+ to bring them in from another yard cuz they didn't have anything out back. I finally found a lot that had one left (out of 5 or 6 cars) for $35. Front end wreak so it wasn't in the dash anymore and the bezel was hosed.....don't know how long the thing was exposed to the weather.....and they still wanted the full $35. Luckily it still works. No more speedo bounce and the AWD seems to be working. Waiting for one last snow storm to really test it out. Thanks again for the help. Link to comment Share on other sites More sharing options...
tforce Posted November 8, 2013 Author Share Posted November 8, 2013 Well, the AWD has stopped working again. The first hard snow hit the other day and........suck. No indications as to what the problem is. No CEL, AT Oil Temp Light, Torque Bind, Speedo Bounce....nothing. Just no AWD. Tranny is shifting fine. Just replaced the pan gasket and the fluid looked fine. I little bit of sparkle in the bottom and some gunk on the magnet but no burning, metal fragments or anything else obviously wrong. Getting tired of working on this car. Was just about to put in a new steering rack, halfshaft and reseal the oil pan. Needs new struts and assorted suspension bushings too. Anyone have any deeper insights on what could be causing this issue? I have access to another tranny but I'm not sure I really wanna keep pouring time and money into this thing. Link to comment Share on other sites More sharing options...
johnceggleston Posted November 8, 2013 Share Posted November 8, 2013 (edited) it is either the sensor, the TCU or the AWD transfer clutch. disconnect the TCU wire connectors under the dash. (or the large connector on the rear of the engine passenger side.) this will put the trans in ''limp mode''. you will have reverse and 3rd gear, no electronics. it will / should also cause torque bind in slow tight turns. (no power to the duty c solenoid) if you do not have TB, the transfer clutch is gone, does not clutch / grab. has the AWD ever worked right? test the speed sensor, (old one if you still have it). use a very slow speed on an electric drill and measure the output with an analog volt meter. or jack up the front right wheel and turn by hand while measuring the output. the needle should jump several times for each rotation. if it is not working you will not have AWD. i do not know why there is no CEL if the sensor is bad. Edited November 8, 2013 by johnceggleston Link to comment Share on other sites More sharing options...
tforce Posted November 8, 2013 Author Share Posted November 8, 2013 it is either the sensor, the TCU or the AWD transfer clutch. disconnect the TCU wire connectors under the dash. (or the large connector on the rear of the engine passenger side.) this will put the trans in ''limp mode''. you will have reverse and 3rd gear, no electronics. it will / should also cause torque bind in slow tight turns. (no power to the duty c solenoid) if you do not have TB, the transfer clutch is gone, does not clutch / grab. has the AWD ever worked right? test the speed sensor, (old one if you still have it). use a very slow speed on an electric drill and measure the output with an analog volt meter. or jack up the front right wheel and turn by hand while measuring the output. the needle should jump several times for each rotation. if it is not working you will not have AWD. i do not know why there is no CEL if the sensor is bad. I do have the old speed sensor so I'll have to track down an analog meter. The AWD did work at one point. I replaced the old tranny with a used one that had TB. I swapped the old rear ext on after grinding down the grooves on the clutch. Everything worked fine till the speedo bounce showed up. Replaced the speedo and that seemed to cure it...pretty much. AWD always seemed to be a little off after that but it did work for the most part. I'm curious to see what results I get from test #1. I doubt it's the sensor because I replaced it with the one from the old tranny and nothing changed but I'll test it anyway. Thanks John. Link to comment Share on other sites More sharing options...
tforce Posted November 9, 2013 Author Share Posted November 9, 2013 it is either the sensor, the TCU or the AWD transfer clutch. disconnect the TCU wire connectors under the dash. (or the large connector on the rear of the engine passenger side.) this will put the trans in ''limp mode''. you will have reverse and 3rd gear, no electronics. it will / should also cause torque bind in slow tight turns. (no power to the duty c solenoid) if you do not have TB, the transfer clutch is gone, does not clutch / grab. has the AWD ever worked right? test the speed sensor, (old one if you still have it). use a very slow speed on an electric drill and measure the output with an analog volt meter. or jack up the front right wheel and turn by hand while measuring the output. the needle should jump several times for each rotation. if it is not working you will not have AWD. i do not know why there is no CEL if the sensor is bad. No TB in limp mode. Time for a tranny swap or maybe just time to get rid of the car and move on....or maybe I'll just park it till spring and work on it then. Anyone want an LSI for a project? It's got a few dings and rust spots already and it needs suspension work so it's a prime candidate for becoming an offroad toy. Link to comment Share on other sites More sharing options...
tforce Posted November 13, 2013 Author Share Posted November 13, 2013 I saw this in another thread so I decided to try it just out of curiosity. I jacked up the drivers side of the car, unplugged the TCU, started the car and put it in neutral. Both wheels started spinning forward. I hit the brakes and after that, just the front wheel spun. I could move the rear wheel by hand in either direction while the front wheel was spinning and I could stop the front wheel by hand. There wasn't enough power behind it to move the car. Putting it in gear only got movement out of the front wheel. I plugged the TCU back in and tried it again. Same deal except the rear wheel didn't spin this time. I got a tiny bit of movement out of the rear wheel for just a second when I put it in Reverse. I have no idea what that means aside from fluid flowing where/when it shouldn't and I still need to swap the tranny. Just thought I'd share. Link to comment Share on other sites More sharing options...
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