ok so this morning im drivin to school, i stop at a stop sign, *CLUNK*, oh crap, wtf was that? i drive off, and i notice that it's in second gear....and won't shift out of it. i pull over, check my reverse, it works ok. i turn off the car, think for a bit, and decide to limp it home, and i start it up and it shifts fine, without so much as a shudder.
so the question is as the title says, what causes limp mode? i have no CEL, and if it werent for the fact that i knew it happened, the car behaves as though nothing is differnt. WTF?
im totally confused, i asked my automotive teacher about it and he said the shift solenoids may have stuck, i didnt know transmissions had shift solenoids, (besides the OD solenoid, on these cars) im used to old stuff, and the only automatic i've ever been worked on is over 30 years old.
oh and all i know about these transmissions is its a 3 speed with an overdrive, and that i need to get it flushed periodicly, and i need to get it a tranny cooler, im working on both of those.
Limp mode is the trannys way of getting you home incase of damage ... It could have been a solenoid pack or TCM trouble ,but the loud CLUNK you desribe may be something far more sinister and prelude to tranny failure (mechanical)
Limp mode is the trannys way of getting you home incase of damage ... It could have been a solenoid pack or TCM trouble ,but the loud CLUNK you desribe may be something far more sinister and prelude to tranny failure (mechanical)
it wasnt a loud clunk, it was the same clunk i get when i drop it into neutral from drive(i suspect the noise is my mounts, but i know those are at the end of their life). the clunk was just horribly magnified in my mind because it shouldnt have happened at that moment. when im driving the slightest click, knock, ping or pop, and it sounds like nails on a chalkboard.
but anyway, i know what limp mode does, but what tells it to activate. what imput does the TCM get to say "lets go into limp mode".
update: its been shifting fine, i've been babying it a bit more than usual. no odd sounds, no odd shifts. if something is mechanicly wrong it acting exactly the same way it has the whole time i've had it. im going to get the tranny flushed soon, and see if the tranny shop will do kind of an inspection for little or no charge. im a bit strapped for cash, to give you an idea, the tranny flush is going to put some serious hurt on my budget. i also need to find the time, most days i don't have an hour or so to sit there and do nothing while my tranny is flushed. i wish there were 24/7 tranny shops, then i'd be set.
if it happens another times first thing to check is if the speedometer AND the rpm are working
the a604 has 2 speed sensors and they are knowned to fail when either one is not sending a signal the tcm put the transmission in limp mode visual symptoms of a bad sensor: 1 of the 2 main gauge will not work
Alain
Logged
do a unique engine swap or die trying bow to the torque meister , the 2.4L prophet
alain, is the fact that my cruise control dies at unpredicable times possibly related to the speed sensors?
also the other day after a longer drive, i checked the fluid and it had a bit of bubbling in the tranny fluid, i'd estimate a guess as to the fact that this is bad. i know one cause of tranny fluid bubbling is overfilling, which i know it is NOT overfilled. i suspect that its getting nice and toasty in there and the fluid is expanding and aerating(getting air in it, bubbling, i don't think i spelled it right, don't want to cause confusion by a misspelling)
it still just has the stock trans cooler, and i've been looking around for a new trans cooler, but i'm concerned that it may be too little, too late.
Author
Logged
