Shift lever is out of wack

[spongebob]

Maybe the linkage, when I pull the shifter into D the light indicator isnt where it should be, and if I go back to Park, it goes into reverse if I move the lever
Slowly it might work…..I’m on a rebuilt trans put in my a Chevy dealer.

Thoughts?

[DmaxMaverick]

If the lever isn't sloppy, look at the cable joint (less likely), or the NSBU switch (more likely). The NSBU can loosen and get out of adjustment, or just break. Unfortunately (or fortunately), the 6-speed NSBU is inside the case, opposite the input shaft, and requires pan removal to access.

[Yukon6.2]

My shifter has become lazy going back into park
I first noticed it when i was backing up to a car to lift it with my wheel lift.I backed up till i felt the arms against the car tires,put it in park and went to lift the car.Had no hydrolics,WTH went back to the truck and saw the indicator in R but the handle was in park.Shifted back into R then to Park and watched the indicator.It didn't move with the shifter.Had to shift it again quickly and the indicator moved.
It's done it a few more times,haven't had a chance to explore the issue.

[DmaxMaverick]

If the detents feel right and the lever doesn't flop around, it's highly likely the NSBU switch is out of adjustment or broken. The lever-cable-linkage is mechanical into the tranny, and the NSBU switch just rides along with the input shaft. Although the lever and tranny may, in fact, be in P and locked, the NSBU communicates the position electronically. If it's off just a little, it will lie.

[spongebob]

If I were to go on ebay and search for this switch, what exact ally would i search for?

[spongebob]

The lever feels “weak” and when I do get into park it clunks..

[DmaxMaverick]

Search for NSBU switch, for your model year. Make sure it's for the 6-speed.

A "weak" lever and a "clunk" going into P may or may not mean something. If the P/TCM "thinks" the tranny is still in gear, and you mechanically force it into P, it may clunk (pressure still on the engaged clutches). It may also mean an actual mechanical issue with the shifter or linkage. Have someone operate the lever (engine OFF, brake set, wheels chocked!) while you watch the input linkage, and note any sloppiness. It should have none, or near none. Check each position, and the transition between them. If the linkage is tight, the issue is likely the NSBU, or an internal mechanical failure.

[spongebob]

https://www.merchant-automotive.com/Allison-1000-6-Speed-NSBU-Switch-2006-2016-Duramax

Doesn’t look like fun:

https://www.youtube.com/watch?v=Y8H2YP0w33A

[DmaxMaverick]

If everything functions as it should, but it's out of adjustment, it shouldn't need replacement. It doesn't appear the computer is complaining, so an electronic failure is unlikely. If the tranny shifts normal, the backup lights work, and it will crank or not crank as it's supposed to, the switch is probably good. The switch can be adjusted without removal. Still, you need to verify the linkage from the lever to the tranny input is solid. Repeat the process that allows the lever to be in P, while the display indicates R, then move the cable at the input shaft to see if it will indicate correctly.

[spongebob]

Seems the lever is out of wack, I just checked the reverse to see if it lights up and it did, but when I went into park it was in neutral neutral lite was indicated
Even though the lever was all the way up. Couldn’t get it into park, shut it off in neutral..

Indicator light is showing it’s in neutral shift
lever is in the park position can’t get reverse or park.

Could it be the ignition switch?

[DmaxMaverick]

I don't see how the ign switch could cause this. The lock cylinder will prevent it from shifting from park when OFF, but does nothing beyond that.

When you say you shut it off in Neutral, do you mean the lever was in neutral position, and the truck would roll? Or, was it just indicating Neutral, but the lever was all the way up? If all the way up, does the truck roll?

[spongebob]

I can get neutral, the indicator light says I’m in neutral but the lever is up where park and reverse is..right now I’m in neutral and can remove the key. On a side note, last winter I went off the road in deep snow, into a culvert and had to be pulled out. I’m wondering if the linkage could of gotten beat up.

[spongebob]

Found this: “ How to Know The Gear Shifter is a Problem
As with any possible arising problems, your Chevrolet Duramax may experience several signs and symptoms of a faulty or failed gear shifter. The gear shifter is an extremely important component of your vehicle, as without it, your vehicle cannot initiate motion.
One commonly-reported warning sign of a gear shifter problem is an unresponsive shifter. When you move the gear shifter of your Chevrolet Duramax, a linkage moves with it allowing gears to change. If your vehicle does not seem to engage in the gear you selected, it is likely the linkage has become damaged or broken.”

[DmaxMaverick]

OK. More "if's"...

If the lever goes into the "P" position, and you can remove the key, the lever and lock cylinder are not failed.

If it remains indicated "N", with the lever in the "P" position and you can remove the key, is the truck able to roll (parking pawl engaged or not, this is VERY important)?

We're back to a very simple process...

IF the lever is in the P position and you can remove the key, but the truck is able to roll, the problem will be mechanical. Meaning, the problem will be the shift linkage after the lever, and before the tranny range selector input.

IF the lever is in the P position and you can remove the key, but the truck is NOT able to roll (parking pawl engaged), the problem will be electronic. Meaning, despite the physical position of the lever, the NSBU is not reporting the range selector input shaft position correctly to the computer.

[spongebob]

Let me get a charge on my lap top, I’ll go out and go though your scenarios….

[spongebob]

Truck is running, indicator light is on in neutral, shift lever is all the way up, shifting into “D” works. I can remove key when Lever is up and indicating neutral. I can roll truck with lever all the way up in the park position but reading ‘neutral”..

[DmaxMaverick]

In that case, it appears your suspicion of damage when hitting the culvert may be in the right direction. On the bright side, it sounds to me like the damage is external to the tranny. That really cuts down on the time and cost factors. You're just going to have to get under there and find the damage. If the cable was snagged by something, it could be damaged at any point. If it isn't obvious, I'd suspect the coupler, if it has one, or a cable bracket (at either end). Trace the cable from the tranny forward. You may have to remove the driver seat and pull up the carpet (I'm not familiar with the 2006 cable routing, or if it's actually a 2-piece cable, but don't know otherwise).

[spongebob]

Thanks…I’ll let us know what it is/was

[spongebob]

Found the problem, my off roading into the culvert knocked the shift linkage out of it’s bracket.
There are two “clips” that hold it in place and one is missing..so looks like I’ll buy a new linkage
Cable and install it….hope there’s a YouTube video.
Thanks Dmax for your help..

[DmaxMaverick]

Glad you found it.

Is the cable damaged, or just displaced? If only a plastic tab is missing (broken off), I'd probably improvise a repair. A hose clamp, for example, would be at least as secure as the plastic clips. You shouldn't have to replace the cable unless it's actually broken.

[spongebob]

I have it zipped tied, If I can find the end piece that attaches to the shift point
On the trans, I’ll replace it, but so far I can’t find it online.

thanks again for your help…

[DmaxMaverick]

I don't trust zip ties for anything other than tying up wires. They tend to break for any reason or no reason. I use them for any number of things, but trust them to break at any time. The reason I suggested a hose clamp. Even bailing wire or a shoe string would be better, IMO.

I doubt you'll find only the end piece. Maybe a repair kit, but it's likely only available with the cable assembly. If the 2006 cable is a 2-piece like previous models, you'll only need that end of it. The coupler is a PITA, but much better than replacing the entire cable.

[spongebob]

I buy the good ones. Nothing from China. yes it looks to be a two piece cable . If you buy the “white” ties make sure there’s no discoloration,
will look yellowish, that’s recycled nylon and will break.