Hi I have a 2005 corvette Z51 MT 6 speed. I have onwned the car since new and it has 36000km's and has not been driven hard.

The car will not shutdown unless it is parked in reverse - this is only for the 2005 model from my understanding.

The dealership tried replacing the reverse switch but that did not fix it so they took it back out and said I would need a new transmission. I also have an issue with hard shifting when the transmission is hot and only downshifting.

I haven't seen anyone else with this issue to date.

Any advice on this would be very much appreciated.

Craig

 

I have not heard of this problem myself. So, I'm assuming that with your current problem you do not have any reverse light functions when backing up either, correct? I'd definitely get a second opinion before buying a transmission. The reverse light circuit is usually pretty simple. It sounds to me like they are telling you that the part inside the transmission that actuates the reverse light switch plunger is broken. With a decent multi-meter and common knowledge of electrical systems, it should be easy to diagnose and verify if they are correct.

You would just need to access the electrical connector of the reverse light switch on the side of the transmission. Unplug the connector and check for continuity (a complete circuit) between the 2 pins ON THE SWITCH. Move the shifter from first gear to reverse a couple times and watch the reading on the meter. In reverse, you should see a complete circuit; in any forward gear it should be an open-circuit. If its open-circuit at all times, then there is a problem with the switch or what is supposed to actuate it.

The next step would be to perform the same test with the switch removed from the transmission. This time, you would actuate the switch by hand and monitor the results.

If the switch tests okay when manually operating it but not okay when installed in the transmission, then there is a problem with the transmission. If it fails both tests, its a bad switch. If it passes both tests, its a wiring problem.

Hope this helps,

Andy

 

Hi Andy

Thanks for your reply. The car will recognize it is in reverse once I shut it off when the shifter is in reverse; then I pull back the shifter very slightly. It seems like when it is hot though it doesn't recognize it is in reverse even when I pull back on the shifter.

Is it likely that it is something in the transmission - like a small gap when it is in reverse and that is why it only recognizes it when I pull the shifter back a tiny bit?

Thanks

Craig

 

As long as the car recognizes reverse for a few seconds on shut down, you can actually leave the car in any gear you want. Just don't do anything else until the car sits in that recognized reverse for a least a few seconds.
Do you know if the car has had the DBS BCM reflash upgrade?

 

I haven't had the BCM reflast - although I have heard about it on this forum. The dealer never suggested it but I am thinking of taking it in and seeing if that helps, although most people who need the BCM upgrade do not get the message to put the car in park to shutdown as I do.

 

You mean reverse. And I did from time to time before I got the reflash.

 

Your comment here & the following replies leave me confused. What do you mean by "the car will not shutdown unless is is parked in reverse"? That is normal for the '05 MN6's (only). For some reasn, the design is such that the various electrical circuits will not shut down completely unless the trans is in Reverse on shut down (& remains in Reverse). I've had my '05 since new & it's always operating that way....on some occasions when I forgeot & shut down in Neutral got a big surprise the next morning with a dead battery. Exactly what problem do you think is occuring?

 

What happens is that when I park the car in reverse it wont shutdown and gives me the message to put the car in reverse - for some reason it is not recognizing it is in reverse already - then when I pull back on the shifter slightly it will recognize it is in reverse and shutdown. So as long as the transmission is not too hot this works - but when the transmission is hot after I have been driving for an hour or so, it is hard to downshift and it will not recognize it is in reverse even when I pull back slightly on the shifter so it will not shutdown at all.
the dealer thought it was the reverse switch that was defective but when they changed it, the car still had the same problem. The dealer said they believe the problem is in the transmission and I need a new one - surprising as the car only has 36000kms or 23000miles and has not been driven hard. In Canada it will cost me 8000.00 to replace the transmission.
I think I will ask them to reflash the BCM - although I don't think this will fix the issue.

Thanks to all who have offered suggestions so far, any other thoughts would be appreciated.

Craig

 

Get the reflash and follow what I've told you. Monitor the car by peeking into the closed car every day. If the red light near the radio is still flashing after 48 hours, then you probably will do fine with your shutdown. If you get dead batteries at 24-48 hours after shutdown, then you will have either leave the battery on a charger/tender, or get a prioritystart module installed.

http://www.prioritystart.com/

 

No problem. I forgot that you were also having problems with the transmission shifting properly when it was hot. Not sure if this is related to your reverse gear detection problem. If the reverse activation problem was the only issue, there could be some ways to fix that issue with a little ingenuity. But since you are also having shifting problems, is might be more to this.

Another thing that just crossed my mind could be an issue with the shifter or carrier. I'm wondering if when things get hot (shifter box bushings, etc.) the box and shifter are moving around/expanding and preventing reverse from engaging properly. This would also explain the hard shifting into other gears when hot. This is the only thing I can think of that links your two problems.

Did the tech working on the car inspect the shifter at all? I'm just wondering how they diagnosed this to be an internal tranmsmission problem. I am a Technician, BTW. I just do German cars for a living. Hope you get to thwe bottom of this and that it Does not need a transmission .

Andy

 

Hi Andy

Yes the technician did check the shifter as well as replacing the reverse switch.

I am taking it into the corvette specialties service department in Vancouver this week. Hope they have better news that the dealership - I would hate to spend 8k just so the car recognizes it is in reverse . I will mention the BCM reflash to them;l although I don't think my problem is the same as the DBS issue as the lights wont go off and the doors wont lock if I am not able to put the car in reverse - I just have to wait for it to cool down before it will finally recognize reverse when I jiggle the shifter.

If anyone else is aware of this problem I would love to know what the diagnosis was.

Craig

 

I just spoke with corvette specialties about this issue and they said that the plunger in the transmission is not going in far enough so that the car wont recognize its in reverse. he said they should be able to modify the plunger from outside the transmission so it engages earlier. Does this seem correct to any of the experts out there?

Hope this helps anyone else who is having a similar issue, as it seems pretty rare on this forum.

Craig

 

It is rare, and seems like a sensible and much cheaper solution if physically doable.

 

They said they did the same thing last week so hopefully it will work for me. Compared to GM service's solution of a new transmission for 8000.00, plus tax, when the transmission works perfectly according to them.

 

Okay, that is what I wanted to confirm. Like I said before, there could be a "creative" solution to the reverse switch problem if that was the cause.

Are you not worried about the shifting problems?

Andy