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1997 GMC Sierra 1500 transmission help

socomkingz

By socomkingz
in Ask A GM Technician

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socomkingz Enthusiast

socomkingz

Posted
Posted

Ok here's the problem. It's NOT the cable or shifter itself.... 1997 GMC Sierra, when I start it in park, the park light is not on. When I am underneath it, when the truck is in 1, the 1 light on the dash is on... When I put the truck into 2, the light still shows #1.... When I click the transmission into 3, The light on the dash illuminates as #2.. This is a problem because when I put my truck into what SHOULD BE neutral, my trucks reverse gear is actually activated. This is not slack in my cable as the cable is disconnected.... Again when I put the truck into park, the park light doesn't illuminate. It's like all the gears dropped down one, on the dash, and 2 and 1 both share the #1 gear indicator

Doug_Scott Senior Enthusiast

Doug_Scott

Posted
Posted

If you completely ignore the shift quadrant(PRND21), and move the shift lever down one notch or click, is the truck now in reverse? If you move the lever down one more notch or click, is it now in neutral? One more notch or click, is it now in drive? You can see where this is going.

 

If the transmission gear selection matches the actual shift lever position on its internal detents/notches/clicks, then your issue is with how the PRND21 is calibrated. I have no idea if it is completely electric in your truck, or if it still uses the old way. The old way is a little cable that pulls the needle or light bulb or some other way of filtering the display.

 

Driving it with the indicator being off is no big deal. If you pay attention to the shifter you will find that once you move the shifter down one spot, that will be reverse, and then if you just put your hand flat on top of the lever and push straight down, it will stop in drive. To get into 2 or 1 you have to pull the lever. Once in drive, if you push straight up, it will stop in neutral. Reverse requires you to pull the lever. Not sure when I last looked at the indicator.

 

Make sure that the truck only starts in park or neutral as well.

socomkingz Enthusiast

socomkingz

Posted
  • Author
Posted

If you completely ignore the shift quadrant(PRND21), and move the shift lever down one notch or click, is the truck now in reverse? If you move the lever down one more notch or click, is it now in neutral? One more notch or click, is it now in drive? You can see where this is going.

 

If the transmission gear selection matches the actual shift lever position on its internal detents/notches/clicks, then your issue is with how the PRND21 is calibrated. I have no idea if it is completely electric in your truck, or if it still uses the old way. The old way is a little cable that pulls the needle or light bulb or some other way of filtering the display.

 

Driving it with the indicator being off is no big deal. If you pay attention to the shifter you will find that once you move the shifter down one spot, that will be reverse, and then if you just put your hand flat on top of the lever and push straight down, it will stop in drive. To get into 2 or 1 you have to pull the lever. Once in drive, if you push straight up, it will stop in neutral. Reverse requires you to pull the lever. Not sure when I last looked at the indicator.

 

Make sure that the truck only starts in park or neutral as well.

I will get back to you on this tomorrow I will try your shifter problem solving

gmtech4 Senior Enthusiast

gmtech4

Posted
Posted

It is a completely electric system to the cluster ,,

 

You have a cable adjustment problem or the mount is broken on the cable end, or the NSBU switch has failed

socomkingz Enthusiast

socomkingz

Posted
  • Author
Posted

It is a completely electric system to the cluster ,,

 

You have a cable adjustment problem or the mount is broken on the cable end, or the NSBU switch has failed

Do you know where and how much the nsbu switch could be? Where I can buy one? 1997 GMC Sierra k1500 , 350 vortec

gmtech4 Senior Enthusiast

gmtech4

Posted
Posted

It's on the transmission shifter shaft , and no idk or care how much it is or where to get it , a store I think may sell them ,,,,

 

Don't just go get one , look at what I said to look at first ,

 

Process of illumination my son !!! Lol

 

Let us know

socomkingz Enthusiast

socomkingz

Posted
  • Author
Posted

It's on the transmission shifter shaft , and no idk or care how much it is or where to get it , a store I think may sell them ,,,,

 

Don't just go get one , look at what I said to look at first ,

 

Process of illumination my son !!! Lol

 

Let us know

The shifter cable is out of the question, I looked at that, I can access all gears, shifter position is proper, the clip holding the cable onto the tranny arm is tip-top shape... I think the last thing would be nsbu switch

Doug_Scott Senior Enthusiast

Doug_Scott

Posted
Posted

The shifter cable is out of the question, I looked at that, I can access all gears, shifter position is proper, the clip holding the cable onto the tranny arm is tip-top shape... I think the last thing would be nsbu switch

 

When you say "I think the last thing would be nsbu switch" are you saying that you do not think that it is the nsbu switch? I really hope that is not what you are saying.

socomkingz Enthusiast

socomkingz

Posted
  • Author
Posted

 

When you say "I think the last thing would be nsbu switch" are you saying that you do not think that it is the nsbu switch? I really hope that is not what you are saying.

Nono, I'm saying the ONLY OTHER THING I can think of is the nsbu switch.. :P Just as I've looked at everything else and if there's no other gear sensors or "transmission position sensor", the last thing on the list is nsbu and I'm hoping it is... Are those adjustable? Or just simply it either works or doesn't work lol

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