What normally fails first on a modern day electronic transmission
From : ron
Q: the reason that the transmission computer is always replaced when a transmission goes out is pre-96 tcms did not have the quick-learn feature re-using the old tcm you are stuck with the cvis that were in it when the transmission failed cvis can be thought of as the controller adapting to clutch wear this causes a severe bind-up on the 2-3 shift for the first 10-12 shifts until the cvis adapt to the new unit; so severe in some cases that it almost throws you into the steering wheel it is possible to rapidly reset them by doing full-bore 3-1 down-shifts about 5-6 times followed by 5-6 of 4-2 full-bore down shifts but until it adapts you are scorching clutches on every shift with the quick learn you hook up a scan tool tell it to learn it instructs you to put the shifter in gears in a sequence the tcm learns that it has a new set of clutches in the pack and re-sets itself ok i just got finished rebuilding my wifes 1989 voyager or at least the engine and front-end. the transmission had been replaced a few years ago. now my question is does the electronics fail first then takes out the rest of the transmission because it is trying for reverse and forward at the same time or does the transmission just fail like most of mechanical transmission from heat i does seem that the transmission computer is always replaced when a transmission goes out. i am questioning if i should replace the computer now and maybe save a transmission bill 3 or 4 years down the road. i live in nr country that is no rust not no rednecks so the rest of the van is in very good shape or i would have never taken this project on. thanks ron .
Replies:
From : ron
put in any lower than 195o in ny state and you might very well fail your emissions inspection next time around .
From : ron
ok i believe the consensus is that the filter is not serviceable nor intended to need service. the fuel pump was replaced about two years ago. symptoms of the vehicle include stumbling and losing power after being driven for a mile or so. sometimes the poor running occurs sooner and sometimes it may make a trip to the store and back without incident. in the past i had associated similar behavior of other vehicles to clogged filters it sounds like this is probably not the case here as the filter must have been designed so large as to never clog are there other usual suspects i should check the cel is not lit and it does work as indicated upon startup. does this mean reading codes would be unproductive thanks martin .
From : ron
all of the replacements have the ql i guess what you are saying is that the tcm transmission computer module doesnt fail but that the internal mechanical parts fail just like in the older transmissions. it was interesting to read about how it works. so replacing a tcm before a failure wont stop a failure. does this mean that if i replaced the computer with a new one it will have the quick-learn feature in it or is a pre-96 transmission stuck with using a pre-96 tcm thanks ron transurgeon wrote the reason that the transmission computer is always replaced when a transmission goes out is pre-96 tcms did not have the quick-learn feature re-using the old tcm you are stuck with the cvis that were in it when the transmission failed cvis can be thought of as the controller adapting to clutch wear this causes a severe bind-up on the 2-3 shift for the first 10-12 shifts until the cvis adapt to the new unit; so severe in some cases that it almost throws you into the steering wheel it is possible to rapidly reset them by doing full-bore 3-1 down-shifts about 5-6 times followed by 5-6 of 4-2 full-bore down shifts but until it adapts you are scorching clutches on every shift with the quick learn you hook up a scan tool tell it to learn it instructs you to put the shifter in gears in a sequence the tcm learns that it has a new set of clutches in the pack and re-sets itself ok i just got finished rebuilding my wifes 1989 voyager or at least the engine and front-end. the transmission had been replaced a few years ago. now my question is does the electronics fail first then takes out the rest of the transmission because it is trying for reverse and forward at the same time or does the transmission just fail like most of mechanical transmission from heat i does seem that the transmission computer is always replaced when a transmission goes out. i am questioning if i should replace the computer now and maybe save a transmission bill 3 or 4 years down the road. i live in nr country that is no rust not no rednecks so the rest of the van is in very good shape or i would have never taken this project on. thanks ron .