I have had a tremendous struggle with this issue. I've replaced one reverse light switch, one reverse lock out switch, one ECM and am now being told its the linkage misalignment.
The dealership is telling me they need to drop the transmission in order to realign the linkage. Ive read several posts about this in our forum and didn't believe this to be true. Could someone confirm or deny this for me please?

 

Is this a manual transmission? If so ....

I'm a DIY type and not a professional. I've adjusted the "shifter box" not the linkage maybe 5 times for various reasons. This requires console removal. There is NO LINKAGE adjustment other than ensuring that the transmission is in neutral when adjusting the shifter box.

I SAY BS ... Get a new dealership!

 

I agree with the above.

If you are even a little bit mechanically inclined go here: https://www.mgwshifters.com/shifters/corvettes/88

This site shows how to replace the shifter. Not that you need too, but show how to get to the shifter installation and the adjustment that Dutch said.

It is worth the try.

 

Replace the tranny fluid with something like Amsoil ATD or even fresh stock GM fluid. 6 speed manuals are notorious for having reverse issues if the fluid isn't happy.

 

Maybe, but is not an adjustment, but a shifter fork replacement if it out surface is cracked off.
Note, shifter is adjusted at the shifter box to torque tube, and not at the trans.
https://core-shifters.com/pages/corv...kage-alignment

To verfiy that the trans has to come apart to replace the worn internal trans fork,
Make sure that the shifter linkage is correctly indexed at the shifter assembly, then pull connector off the reverse switch on the trans (2005), connect a new switch to connector, turn car off with shifter in park, then press new reverse switch plunger in, and make sure car shuts off. If it does, then pull the old sensor out of the trans and do the same. If senor plunger pressed in is shutting the car down, then flash a light inside the channel to look at the outer surface of the shifter fork to verify it grooved and needs to be replace. If not worn, but just not far enough back, then problem is not the trans, but the shifter and it box not correctly indexed isntead (someone may have pulled a after market shift back out, and did not index the stock box and shifter correctly.

Hence on a 2005 T56 trans, you have back up light switch, and park switch as well (they are both the same).



So what is pressing the switch plungers in is the dog leg of the shifter when shifted to reverse.
Also, tech should be able to shift the trans into reverse, pull the sensors, and look in the channels to see if the problem is worn out surface on the dog leg for the plunger, or problem back up at the shifter box with it not indexed correctly instead.

Hell, could be something simple, like someone doing a anti-venon mod to make an after marker shifter shift easier, and put the brass washer on the wrong sensor/detent isntead. Hence back up and park sensors on the trans should have no washers, and should be installed so their shoulders are tight to the face of the trans.

Simply, did the tech verify that the outer surface of the trans internal dog leg was worn out by pulling the sensor with the trans in reverse and looking into the channels in the correct position from the shifter box correctly indexed, or are they just throwing lawn darts at the problem at your expense, until they resolve the problem with a bunch of unnecessary parts swaps?

Truth is, if the outer shifter fork leg surface is slightly worn, and its not depressing the switch detent enough with the shifter box correctly indexed in reverse , not hard to just chuck the park sensor up in a lathe to face back its seating shoulder enough to gain the needed increase plunger depth in the channel to solve the problem with the sensor and the shift fork.

If a4, then could be the shifter assembly micro switch, position switch on the outside of the trans, or just the C180 or C184 connectors that are corroded. On the A6 trans, micro switch again in the shifter assembly, or could be a problem with the TCM that is in the trans.
Note, on the A6 with it internal TCM, you don't have to pull the trans, but just drop the trans pan to get to the TCM on the bottom of it. Also, shifter cable is adjustable at the trans side of the cable, and could just be that it has stretched and just needs to be readjusted.

 

Agreed!