William Posted December 3, 2011 Share Posted December 3, 2011 For a long time now, my Pathy vibrates for a sudden around the ~80km/h range ONLY when the Overdrive is ON. The vibration shakes the whole car and can be felt anywhere you're seated. It ONLY happens when the Overdrive is ON and for a fraction of a second around the ~80KM/H speed range. To illustrate more, - I am cruising on the highway and my RPM starts to get higher - I engage the OD to shift into a higher gear, speed up and lower my RPM - As long as I am speeding above ~80KM/H I am good - I would then press the brakes lowering my speed below ~80 (OD still ON) - The moment I press the accelerator pedal trying to elevate my speed, the car shakes/vibrates for a like a second, engages the higher gear and then picks-up the speed and back to normal. => If I play with "slight Brake"/"slight Accelerate" around the ~80KM range with the OD in the ON position, the car vibrates/shakes every time I lay my foot on the accelerator. I reasearched the FSM and came across this High Speed Vibration notice: Could my problem be in the Propeller Shaft? William Link to comment Share on other sites More sharing options...
RJSquirrel Posted December 3, 2011 Share Posted December 3, 2011 If your driveshaft was the problem, it would do it all the time at a resonant speed(80kph in your case) but it wouldn't matter what gear your transmission was in. Is the engine misfiring? When was the last time the transmission fluid & filter was changed? It sounds to me like your torque converter is failing. Link to comment Share on other sites More sharing options...
nige Posted December 3, 2011 Share Posted December 3, 2011 does it get worse when you let off the gas OD? show me a picture of the truck, how high does the rear end sit? Link to comment Share on other sites More sharing options...
William Posted December 3, 2011 Author Share Posted December 3, 2011 If your driveshaft was the problem, it would do it all the time at a resonant speed(80kph in your case) but it wouldn't matter what gear your transmission was in. Is the engine misfiring? When was the last time the transmission fluid & filter was changed? It sounds to me like your torque converter is failing. That makes sense. If it only happens when the OD is in the ON position and around ~the 80KM range, then it is not the Propeller Shaft. Maybe it is the Torque Converter!! How can I tell? Last I changed the Transmission Oil + Filter was few years ago. But since I don't drive the Pathy a lot (I am always traveling) so in KM-wise, I would say, since 10,000-15,000 KM. William Link to comment Share on other sites More sharing options...
William Posted December 3, 2011 Author Share Posted December 3, 2011 does it get worse when you let off the gas OD? show me a picture of the truck, how high does the rear end sit? No it does not get worse. It is always the same sudden brief Vibration/Shaking when I accelerate/brake around the ~80KM/Hr speed while the OverDrive is "ON". Unfortunately, I don't have a picture with me. As I mentioned I am traveling and the car is still back home William Link to comment Share on other sites More sharing options...
adamzan Posted December 3, 2011 Share Posted December 3, 2011 Mine did that its like the truck is struggling at lower speeds in highest gear. Turns out I needed to replace plugs/wires/cap/rotor because it had a miss under load. Link to comment Share on other sites More sharing options...
William Posted December 3, 2011 Author Share Posted December 3, 2011 Mine did that its like the truck is struggling at lower speeds in highest gear. Turns out I needed to replace plugs/wires/cap/rotor because it had a miss under load. That resembles my case to a great extent. It is only a brief shaking of the whole car at that ~80KM/Hr speed when the OD is ON. My Spark Plugs were recently replaced along with all of the 6 Plug wires. It did not help! What do you mean by Cap/Rotor? Could it be the TORQUE CONVERTER like RJSquirrel suggested? William Link to comment Share on other sites More sharing options...
adamzan Posted December 3, 2011 Share Posted December 3, 2011 I mean the distributor cap and rotor button (under the cap) its the thing all the plug cables go to. Could be the torque converter but at such low mileage I would think it is unlikely. Have you checked your driveshaft u-joints? Link to comment Share on other sites More sharing options...
William Posted December 4, 2011 Author Share Posted December 4, 2011 I mean the distributor cap and rotor button (under the cap) its the thing all the plug cables go to. Could be the torque converter but at such low mileage I would think it is unlikely. Have you checked your driveshaft u-joints? No I haven't. I do plan to take the entire DRIVE SHAFT out for an alignment anyway. Will check them then. However, why do the car SHAKE/VIBRATE around the ~80KM/Hr speed "only" when the OD is "ON". If the OD is "OFF", the car never shakes, but again the RPM keeps going up and I cannot transfer into the 4th gear. Does that mean it is a mechanical problem or electronic? William Link to comment Share on other sites More sharing options...
1994SEV6 Posted December 4, 2011 Share Posted December 4, 2011 No I haven't. I do plan to take the entire DRIVE SHAFT out for an alignment anyway. Will check them then. However, why do the car SHAKE/VIBRATE around the ~80KM/Hr speed "only" when the OD is "ON". If the OD is "OFF", the car never shakes, but again the RPM keeps going up and I cannot transfer into the 4th gear. Does that mean it is a mechanical problem or electronic? William First of all, why would your Overdrive ever be OFF? There's just no reason for that. But to actually answer your question, it definitely sounds like a torque converter. And the reason it would only happen in OD is because the OD gear is special. OD is SUPPOSED to mean that the driveshaft is spinning much faster than the engine. The engine drops way down in RPMs, while you are in a higher gear. This is different because in non-OD gears, the engine spins faster than the driveshaft. This will put your engine at higher RPMs. If someone was messing around with your transmission, then there might be a loose TC bolt, or you might be low on tranmission fluid Link to comment Share on other sites More sharing options...
William Posted December 4, 2011 Author Share Posted December 4, 2011 (edited) First of all, why would your Overdrive ever be OFF? There's just no reason for that. But to actually answer your question, it definitely sounds like a torque converter. And the reason it would only happen in OD is because the OD gear is special. OD is SUPPOSED to mean that the driveshaft is spinning much faster than the engine. The engine drops way down in RPMs, while you are in a higher gear. This is different because in non-OD gears, the engine spins faster than the driveshaft. This will put your engine at higher RPMs. If someone was messing around with your transmission, then there might be a loose TC bolt, or you might be low on tranmission fluid Well, the only reason I leave my OD OFF is due to the annoying vibration I go through at around 80K/H. Before that problem, I used to keep it ON all the time. OMG. What you said rings a bell!! You are probably 100% on the money. I had my TORQUE CONVERTER re-furbished a few years ago by a mechanic. That same mechanic took the whole Transfer case apart and installed at that time a new set of SOLENOIDS. I did notice after that at least 2 (or 3) TC bolts/studs were broken off (probably were too rusty and got broken off under pressure). That mechanic never mentioned this to me at the time which is why I never returned to his shop. I only discovered it a month later when I took the car for a bath at the station and examined it from below while lifted. Could it be just a bad "refurbishment" of the TORQUE CONVERTER or the broken TC bolts? William Edited December 4, 2011 by William Link to comment Share on other sites More sharing options...
1994SEV6 Posted December 4, 2011 Share Posted December 4, 2011 (edited) Well, the only reason I leave my OD OFF is due to the annoying vibration I go through at around 80K/H. Before that problem, I used to keep it ON all the time. OMG. What you said rings a bell!! You are probably 100% on the money. I had my TORQUE CONVERTER re-furbished a few years ago by a mechanic. That same mechanic took the whole Transfer case apart and installed at that time a new set of SOLENOIDS. I did notice after that at least 2 (or 3) TC bolts/studs were broken off (probably were too rusty and got broken off under pressure). That mechanic never mentioned this to me at the time which is why I never returned to his shop. I only discovered it a month later when I took the car for a bath at the station and examined it from below while lifted. Could it be just a bad "refurbishment" of the TORQUE CONVERTER or the broken TC bolts? William I mean....I have no idea why a Torque converter would need to be 'refurbished'. Most likely some BS from a crook mechanic. Ok, you need to know the difference between a "mechanic" and a mechanic. A real mechanic knows what he's doing and how to do it properly. A "mechanic" is a guy with some tools who knows how to effectively rip you off. Generally, about 85% of repair shops are filled with "mechanics" who have no idea what they are doing. Just because they learned how to change a starter in Ecuador doesn't make them a mechanic. Ok, so first wrong piece of info you gave was that Torque converters need to be refurbished. They don't. Second wrong piece of information. Transfer cases don't have solenoids. Third wrong piece of information, when you say "at least (2 or 3) TC bolts were broken off"... well, there are only FOUR bolts. If two..or three of them were broken, then your car would make lots of vibration. Fourth wrong piece of information, the bolts for the torque converter would NEVER be rusted. They are always submerged in transmission fluid (oil), and they would not accumulate rust. FIFTH wrong piece of information, you can't see the torque converter bolts from underneath. What I mean is, you can't see the torque converter or the bolts unless the transmission is separated/removed. When I say "wrong piece of information", I mean that the mechanic lied to you/you were misinformed. Not "you are lying" or anything. Also, I said that transfer cases don't have solenoids. This is true for our Pathfinders (90-95), but more modern electronic T-cases might have solenoids. The torque converter bolts would be rusted if they were rusty prior to installation. That's the only way I can think of. Water should NOT be getting to your torque converter or bolts. Edited December 4, 2011 by 1994SEV6 Link to comment Share on other sites More sharing options...
William Posted December 4, 2011 Author Share Posted December 4, 2011 (edited) I mean....I have no idea why a Torque converter would need to be 'refurbished'. Most likely some BS from a crook mechanic. Ok, you need to know the difference between a "mechanic" and a mechanic. A real mechanic knows what he's doing and how to do it properly. A "mechanic" is a guy with some tools who knows how to effectively rip you off. Generally, about 85% of repair shops are filled with "mechanics" who have no idea what they are doing. Just because they learned how to change a starter in Ecuador doesn't make them a mechanic. Ok, so first wrong piece of info you gave was that Torque converters need to be refurbished. They don't. Second wrong piece of information. Transfer cases don't have solenoids. Third wrong piece of information, when you say "at least (2 or 3) TC bolts were broken off"... well, there are only FOUR bolts. If two..or three of them were broken, then your car would make lots of vibration. Fourth wrong piece of information, the bolts for the torque converter would NEVER be rusted. They are always submerged in transmission fluid (oil), and they would not accumulate rust. FIFTH wrong piece of information, you can't see the torque converter bolts from underneath. What I mean is, you can't see the torque converter or the bolts unless the transmission is separated/removed. When I say "wrong piece of information", I mean that the mechanic lied to you/you were misinformed. Not "you are lying" or anything. Also, I said that transfer cases don't have solenoids. This is true for our Pathfinders (90-95), but more modern electronic T-cases might have solenoids. The torque converter bolts would be rusted if they were rusty prior to installation. That's the only way I can think of. Water should NOT be getting to your torque converter or bolts. Thank you for the reply. Really very informative as always . I fully agree about "mechanic"/mechanic definition. Been there myself! First, I am not very TECHY with mechanical terms but I am fast learner. I may have confused some terms above: - The broken bolts are for the TRANSMISSION itself (not the transfer case). I am not sure, but they may be the ones that hold the transmission to the engine. There is like a dozen of those all around. Maybe that's why the mechanic did not feel guilty about 3 broken ones out of so many :S - The solenoids were changed from inside the Transmission (and not the Transfer case). I saw the old ones (I believe 5 of them, if my memory serves me well) and I bought the replacements from the local dealer. I remember very well ordering them for my 1992 PF XE. The dealer at that time mentioned that Nissan came up with a new design for these solenoids replacing the ones that came from factory and proved to be somewhat faulty/unreliable. - I agree about the Torque Converter. What ever he did to it, did not make it better. I remember he took it out and gave it to a specialist who refurbished it using some sort of a rotational balancer/trimmer thingy! I guess I am in need for a new Torque Converter and a way to replace those bolts that were broken. William Edited December 4, 2011 by William Link to comment Share on other sites More sharing options...
1994SEV6 Posted December 4, 2011 Share Posted December 4, 2011 Thank you for the reply. Really very informative as always . I fully agree about "mechanic"/mechanic definition. Been there myself! First, I am not very TECHY with mechanical terms but I am fast learner. I may have confused some terms above: - The broken bolts are for the TRANSMISSION itself (not the transfer case). I am not sure, but they may be the ones that hold the transmission to the engine. There is like a dozen of those all around. Maybe that's why the mechanic did not feel guilty about 3 broken ones out of so many :S - The solenoids were changed from inside the Transmission (and not the Transfer case). I saw the old ones (I believe 5 of them, if my memory serves me well) and I bought the replacements from the local dealer. I remember very well ordering them for my 1992 PF XE. The dealer at that time mentioned that Nissan came up with a new design for these solenoids replacing the ones that came from factory and proved to be somewhat faulty/unreliable. - I agree about the Torque Converter. What ever he did to it, did not make it better. I remember he took it out and gave it to a specialist who refurbished it using some sort of a rotational balancer/trimmer thingy! I guess I am in need for a new Torque Converter and a way to replace those bolts that were broken. William No worries. NPORA is here to help you. What you said makes much more sense if you replace the term "transfer case" with "Transmission". No harm done. I understand much better. Yes, I believe there are 14 bolts all around for the transmission. I would say that they are all important. You should probably have all 14 I am also a fast learner. Would you believe that last month I didn't even know what anything meant? Anyway, I may have been a little harsh. I might not have given him enough credit. Especially if he successfully replaced solenoids in a transmission. If you need some extra parts, you're in lucky. I just removed my A/T and everything associated with it. I have the torque converter, the trans pan, all the bolts for the trans, I have the torque converter bolts, I have the flywheel, the flywheel bolts, I have the shifter. Sorry, I don't want to advertise, but just send me a PM. I promise I'll beat the dealer prices. Let's see if we can get you sorted out Link to comment Share on other sites More sharing options...
adamzan Posted December 5, 2011 Share Posted December 5, 2011 I wouldn't want a torque converter that was starved of fluid ^^^ Link to comment Share on other sites More sharing options...
1994SEV6 Posted December 5, 2011 Share Posted December 5, 2011 (edited) I wouldn't want a torque converter that was starved of fluid ^^^ That's true. It was run without fluid for about a half mile. I wasn't trying to hide that or anything. Would it really matter? Isn't it just a metal donut that is connected to the engine? If it's low on fluid..it just won't power the transmission. Would any damage to the actual torque converter occur? I mean, that's like saying "oh, your transmission was starved of fluid, therefore I don't want to buy your shifter". Like..it's not related, is it? Edited December 5, 2011 by 1994SEV6 Link to comment Share on other sites More sharing options...
sewebster Posted December 5, 2011 Share Posted December 5, 2011 Presumably the rotor in the torque converter has to be mounted on a bearing or something to keep it in the right place. Probably that bearing requires lubrication to not eat itself. Shrug. Link to comment Share on other sites More sharing options...
1994SEV6 Posted December 5, 2011 Share Posted December 5, 2011 oh nvm then. Mine isn't for sale. I was going to sell it for the cost of shipping, but I wouldn't want you to do all that work just to find out that it's broken and you have to tear it out again. Link to comment Share on other sites More sharing options...
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