gzibell Posted October 30, 2013 Report Share Posted October 30, 2013 Hi, Just joined the forum looking for some advice. Stopped by here a few times to find other info but I am stumped on this one. Got a 98 grand prix gtp with 275k on it. Have not had to do any major repairs except replace the fuel pump about 6 years ago. Owned it since about 2002. Last night I started having a strange issue with the tranny in some way. When I am accelerating or decelerating everything is fine. When I either hold a speed or set the cruise things get weird. Rpms star jumping up and done maybe 500 repeatedly, with that I get speed variations(can feel brief moments of slowing down and speeding up), and I can feel/hear repeated noises. All of these things happen together at the same time. I feel like the only way to describe it would be imagine lightly setting the emergency brake when driving a manual, getting up to 55, holding your foot on the gas to hold 55 and then repeatedly massing the clutch to the floor and back. Does that make sense? Looking for some suggestions, I did buy some magic in a bottle and dumped that in to see if it helps. Quote Link to comment Share on other sites More sharing options...
l67ss Posted October 30, 2013 Report Share Posted October 30, 2013 When was the last time the tranny was serviced? Hi, Just joined the forum looking for some advice. Stopped by here a few times to find other info but I am stumped on this one. Got a 98 grand prix gtp with 275k on it. Have not had to do any major repairs except replace the fuel pump about 6 years ago. Owned it since about 2002. Last night I started having a strange issue with the tranny in some way. When I am accelerating or decelerating everything is fine. When I either hold a speed or set the cruise things get weird. Rpms star jumping up and done maybe 500 repeatedly, with that I get speed variations(can feel brief moments of slowing down and speeding up), and I can feel/hear repeated noises. All of these things happen together at the same time. I feel like the only way to describe it would be imagine lightly setting the emergency brake when driving a manual, getting up to 55, holding your foot on the gas to hold 55 and then repeatedly massing the clutch to the floor and back. Does that make sense? Looking for some suggestions, I did buy some magic in a bottle and dumped that in to see if it helps. Quote Link to comment Share on other sites More sharing options...
gzibell Posted October 30, 2013 Author Report Share Posted October 30, 2013 When was the last time the tranny was serviced? Maybe 6 or 8 months ago...local shop hooked up a machine that ran some detergent stuff in there for a while pulled the fluid and replaced with new. Don't think there was a filter involved though. Been working fine up until yesterday and today though. I thought the tranny might be going out but if I mash the break and gas it only revs up up to about 3k and boy oh boy when you step on it does it still go. Quote Link to comment Share on other sites More sharing options...
BS009 Posted October 30, 2013 Report Share Posted October 30, 2013 Sounds like the torque converter solenoid could be going out. There's a few solenoids in these transmissions that seem to go out every ~150,000 miles it seems. Usually it's the pressure control solenoid but the shift solenoids, and torque converter solenoid also go out. Couple things I would check though just to make sure: - Check transmission fluid level - Make sure plugs and wires are in good shape. You might also want to check out your coils and ignition control module too since you have so many miles on it. This one's a longshot but it might help out. Pull off the negative battery cable for a minute to let the pcm reset. I've heard there's a variable that the pcm learns over time that controls how much pressure is used during each shift. If it learns the wrong pressure because of a shift that took too long or a shift that was too quick then it could cause problems when there isn't really one to begin with. It's unlikely that this is the issue but it's worth a shot. It sounds like the same issue I was intermittently having with my car a couple weeks ago and this solved the problem. I figured mine wasn't a solenoid because I just rebuilt the transmission myself and replaced all of the solenoids. Unplugged the battery cable, plugged back in and it has been fine ever since. Quote Link to comment Share on other sites More sharing options...
l67ss Posted October 31, 2013 Report Share Posted October 31, 2013 What he said btw there is a filter and it needs to be changed every 30-50k miles Sounds like the torque converter solenoid could be going out. There's a few solenoids in these transmissions that seem to go out every ~150,000 miles it seems. Usually it's the pressure control solenoid but the shift solenoids, and torque converter solenoid also go out. Couple things I would check though just to make sure: - Check transmission fluid level - Make sure plugs and wires are in good shape. You might also want to check out your coils and ignition control module too since you have so many miles on it. This one's a longshot but it might help out. Pull off the negative battery cable for a minute to let the pcm reset. I've heard there's a variable that the pcm learns over time that controls how much pressure is used during each shift. If it learns the wrong pressure because of a shift that took too long or a shift that was too quick then it could cause problems when there isn't really one to begin with. It's unlikely that this is the issue but it's worth a shot. It sounds like the same issue I was intermittently having with my car a couple weeks ago and this solved the problem. I figured mine wasn't a solenoid because I just rebuilt the transmission myself and replaced all of the solenoids. Unplugged the battery cable, plugged back in and it has been fine ever since. Quote Link to comment Share on other sites More sharing options...
gzibell Posted October 31, 2013 Author Report Share Posted October 31, 2013 Definitely the TCC solenoid. When I am running down the highway at a set speed the tcc will attempt to lock up and that is when all the craziness starts. Tap the brake quick and it all stops. Starts to go into lock up again and everything starts. Fun It seems to be better today than it was yesterday so hopefully there was just a chuck of crud stuck on/around/by it. Maybe the magic in a bottle will help. (Sea-foam Trans Tune). I sense I will be learning about dis-assembling an atuo trans to replace solenoids in the near future. Quote Link to comment Share on other sites More sharing options...
BrianG Posted October 31, 2013 Report Share Posted October 31, 2013 Replacing the TCC isn't all that bad, and I've done it in my swapped 91 without pulling the trans. You just need to pull the driver side axle out, and drop the cradle and trans down enough for the side cover to clear the frame rail when you take it off. I suppose it might be a little different in a 98, but I don't know for sure. Just don't strip the torx bolts along the bottom!!! Quote Link to comment Share on other sites More sharing options...
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