Back Up Light Switch Engagement Conundrum

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MN1968Valiant

MN1968Valiant

In College's Stranglehold
Joined
Sep 26, 2009
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Location
Eden Prairie, Minnesota
Wow, I have been away from this website for a long time!

I am deep into the process of a meticulous teardown, cleaning, and rebuild of the iron case 833OD that I swapped into my Valiant two summers ago. I just started reassembling the transmission yesterday evening. After installing the entire reverse assembly, I actuated the reverse lever to ensure proper actuation of the mechanism. At this point I noticed that the reverse lever does not rotate rearward far enough to contact the ball which closes the back up lamp switch--there is probably a 0.060" gap, and stacking feeler gauges indicated about 0.082" of extra rearward motion would close the switch.

Long story short, after making a couple of calls, it was suggested to me to turn down the gasket seating face of the switch with a lathe to increase the protrusion of the ball end into the case. However, after speaking with my machinist, it was clear that he was hesitant to turn the switch for fear of weakening or breaching its already-thin, hollow metal case. He instead suggested deeper inspection of the whole assembly to see if I missed anything. In taking his advice, I determined that the true cause for the issue is that the reverse lever is prematurely contacting the tip of the large detent plug that houses the reverse spring and ball.

So now I'm stuck trying to decide what to do. Do I file on either the reverse lever or the detent plug tip where they interfere (risk messing up the otherwise good engagement of reverse gear), or do I put a tiny weldment onto the end of the reverse plug (don't really want to weld on the lever shaft) to fill the gap space?
 
Robbie2734 said:
If you mean weld a blob on the switch, I don't think thats a good idea.
Click to expand...

No, I mean weld a little dot on the back of the reverse lever arm itself, not the switch ball.

bremereric said:
If all else fails call the 4 speed tranny specialist's at Brewer's Performance.
Click to expand...

Believe me, Brewer's was the first call I made, but they were as baffled by the whole thing as I am.
 
MN1968Valiant said:
No, I mean weld a little dot on the back of the reverse lever arm itself, not the switch ball.



Believe me, Brewer's was the first call I made, but they were as baffled by the whole thing as I am.
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Welding the arm might do it but there is something going on thats not correct. Do you have the correct switch? There are 2 that I know of, a 2 post and a 3 post. I'm pretty sure they can't be interchanged, the contact arm won't work. This might be your problem.
 
MN1968Valiant said:
No, I mean weld a little dot on the back of the reverse lever arm itself, not the switch ball.



Believe me, Brewer's was the first call I made, but they were as baffled by the whole thing as I am.
Click to expand...
This is what I`ll do if I ever open my trans up again.
The aftermarket switches are just a tad too short, so I put my leaky OE one back in just to have lights.:protest:
 
Robbie2734 said:
Welding the arm might do it but there is something going on thats not correct. Do you have the correct switch? There are 2 that I know of, a 2 post and a 3 post. I'm pretty sure they can't be interchanged, the contact arm won't work. This might be your problem.
Click to expand...

I have a two-post switch.

mopar head said:
This is what I`ll do if I ever open my trans up again.
The aftermarket switches are just a tad too short, so I put my leaky OE one back in just to have lights.:protest:
Click to expand...

Actually, I have two of said two post switches, and if I understand correctly, one of which is the new style and one of which is the old style. The new style has the "jam nut" style short hex ring, with only the switch prongs exposed through the plastic portion, while the old style has a longer hex section and fully exposed switch tabs? In any case, I tried both, and neither worked.
 
I'm sort of in the same boat. I had an original switch in my trans when I first got it and it's just short of turning on the lights. The lever contacts the ball on my switch, but if I take my hand off of the shifter the lights go out. I have to keep some forward pressure on the shifter to keep the lights going. Found out the switch was leaking when I rebuilt the trans, so I got a new style one hoping it would fix the problem (figured maybe the old switch was just a little worn out), but had the same problem. Thought it may have also been the shifter linkage not giving me enough throw, but I got all new linkage during the rebuild as well and still the same problem.

I thought about putting a little weld on the lever arm where it contacts the switch on the inside of the trans. I really don't think that would hurt anything, you'd only have to put a little bead on the end of it and grind it so it transitions okay when it's engaging the ball on the switch.
 
Robbie2734 said:
Welding the arm might do it but there is something going on thats not correct. Do you have the correct switch? There are 2 that I know of, a 2 post and a 3 post. I'm pretty sure they can't be interchanged, the contact arm won't work. This might be your problem.
Click to expand...
I've never seen a 3 wire backup light switch. What year and model uses those?
 
If that's the case, I've never seen a two wire one for and automatic!
 
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