I had the transmission replaced a few months ago and all was fine until recently. If i brake hard and bring the car to an abrupt stop (that "oh $#i+" moment when the light turns red right and you're going a bit too fast.) the tranny feels fine; however after a few moments (30-40 seconds) the tranny will downshift extremely hard to the point it feels like someone rammed into my back bumper while I'm at a dead stop. (Yes I have gotten out of the car to make sure no one hit me, and yes I have looked like a fool coming out of my car at a red light to look at my bumper :shifty: . During the weird shift, i can feel the car drop as if I had put in drive and floored the gas pedal (best way to describe it.) Under normal braking proceedures the tranny does not do any of what I described above, it just simply works fine. Anyhow, I'm not getting any codes either. Any idea's? PCM maybe?
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Harsh downshift when stopped
- Thread starter fudge12
- Start date
Telco
Dedicated LVC Member
The PCM would be my guess. It's also far easier to pull the computer than to dig into the trans for anything. If the place says the PCM is the issue, go ahead and replace all the COPs and plugs before putting the new PCM in as it's suspected that marginal coils backfeeding the trigger line is what causes the PCM to fail. Even if the PCM is not the issue it's still where I would start, and the repair shop just charges a minimal inspection fee if they don't find a problem. Even doing the work yourself anything inside the trans you replace will be more than six times the PCM inspection cost.
The hardest part of the PCM repair is getting the glove box out because the door retainer isn't obvious. There's a button and slot arrangement that holds it in and it requires you to pull the arm to the side at the right spot to get it out as I recall. Then there's also a wire cord attached to the driver side of the box itself, on the outside of the box, that has to be removed. A couple of the bracket bolts are hard to get to as well. Finally, the PCM won't move unless the wiring harnesses are removed completely. Make sure to tape over the plugs and the hole the PCM goes in if the car is parked outside because without the airbox assembly there rain water will pour right in.
The hardest part of the PCM repair is getting the glove box out because the door retainer isn't obvious. There's a button and slot arrangement that holds it in and it requires you to pull the arm to the side at the right spot to get it out as I recall. Then there's also a wire cord attached to the driver side of the box itself, on the outside of the box, that has to be removed. A couple of the bracket bolts are hard to get to as well. Finally, the PCM won't move unless the wiring harnesses are removed completely. Make sure to tape over the plugs and the hole the PCM goes in if the car is parked outside because without the airbox assembly there rain water will pour right in.