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What normally fails first on a modern day electronic transmission ?

OK I just got finished rebuilding my wife's 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

Reply to
Ron
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the reason that 'the transmission computer is always replaced when a transmission goes out' is:

pre-96 TCM's did not have the 'quick-learn' feature

re-using the old TCM, you are stuck with the CVI's that were in it when the transmission failed (CVI's 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 CVI's 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

Reply to
TranSurgeon

Seems to me they would have a way to reset the controller (TCM) to get it back to some safe generic settings. No wonder it costs so much to repair a car now. The scary part is what percentage of people working on this stuff actually know what they are doing? Everything is getting so frigging complicated.

Al

Reply to
Big Al

I guess what you are saying is that the TCM (Transmission Computer Module?) doesn't 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 won't 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

TranSurge> the reason that 'the transmission computer is always replaced when a

Reply to
Ron

Yes it is and yes it isn't. I sure do prefer items like fuel injection and electronic spark control over the old mechanical ways but at this point I think I still prefer the older transmissions.

Reply to
Ron

all of the replacements have the QL

Reply to
TranSurgeon

Is there anyway to look at the module and tell if it the QL version or not ? This transmission was replaced around 1998. It would be my luck that the TCM was old stock without the QL.

Thanks Ron

TranSurge> all of the replacements have the QL

Reply to
Ron

yes, should have told you

the upgraded TCM has 'fins' along one of the long sides

transmission

Reply to
TranSurgeon

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