Neutral safety/backup switch trouble

[quagmire]

For whatever reason, my backup lights will not come on.  I've narrowed the problem down to the switch staying open in reverse, but it tests out okay.  It seems like the valve body detent is depressing it in all positions, but the neutral safety switch works fine still.  The detent looks like the correct one for my car too.  I swapped in another switch and it does the same thing, so I am pretty sure it is indeed a valve body problem.  I dont know what else to try except maybe grinding down the switch contact, but then I think the lights may be on in all positions.  This is on a 904 trans with a CRT valvebody, if anybody has any ideas it would be a great help.Thanks again! -Dan

[tactransman]

Dan,is the plastic piece on the valve body rooster comb OK?

[quagmire]

Yeah, it looks fine.  It's not broken or loose at all.  I had to yank the trans due to several torque converter bolts coming loose and shredding my supposedly bulletproof SFI cert. flexplate (oops).  This time I'm putting red loctite on those bolts!  I also pulled the pan to readjust the low/reverse band and make sure everything is okay.  When it is in the reverse position the switch contact is still depressed a little bit.  I've tried two switches just to rule that out as a possibility and they both did the same thing. 

[tactransman]

Did you try hooking up the plug in to the switch with the switch off the tranny and then pushing the switch button in and out to see if they blink on or anything?

[quagmire]

Yup, the switches work fine when I bench test them.  Thats why I think it may be something to do with the valvebody rooster comb or manual lever.  Not really too sure what to do about it though.

[tactransman]

Try it with out a gasket (for a test) or with two, (stacked) to shim it out a little.

[quagmire]

With the two gaskets stacked it works just fine!  Weird.  Do you think they'll seal okay stacked like that?

[tactransman]

Yup,they should seal fine. The switch was too deep. That is a little trick I learned (stacking two gaskets) 

[quagmire]

Excellent. Thanks, yet again for your help!

[DAYLEY/CHALLENGER]

I have the opposite problelm.   My backup light comes on in any gear.   When you talk about 2 spacers, the new  switch came with a seal and the old switch had only a metal ring around the seal area.  Would the metal ring placed up against the new seal space the switch enough to correct my problem?   Thanks, David

[hemiken]

  It is a possability.  Change them over and let us know what happened.  Hope this works for you this time.

[tactransman]

Did you check to see if the switch works correctly on the bench like Dan did?