The weather in the Valley of the Sun the last few days has been great! Lots of rain. Not being a desert lover, it’s been great! But, now a new situation tonight. Had to "slog" thru about 2-4 inches of standing water to get feed to the barn out back for the hay-burners we call family. No problems getting in, 4 HI, idle, easy as it goes, don't make tracks or get stuck in the pasture area.

Same version coming out of the barn, 4 HI, idle, same tracks in as out. About 150 feet into the "crawl" out of the pasture area things start acting different.

1. I noticed the PRND indicator lights on the dash flickering for a second or two
2. The radio dies for < half a second, then restarts playing
3. truck stops moving forward immediately after the radio begins playing again
4. PRND indicator shows I am still in gear but as I increase the throttle (thinking I might have slipped a wheel) the RPMs increase a few hundred but there is no forward motion. :eek:
5. I let the engine idle back down
6. Slip lever to next lower gear and off I go again. For about 3-4 feet.
7. EXACTLY the same scenario as 1 thru 5. I slip into "2". Same as #6.
8. Go back to Drive. Ditto #6, then 1 thru 5 again
9. I did this same scenario thru all gears (up or down) to get out of the pasture/yard

I nurse the truck out to the street 3-4 feet at a time and never once spun a wheel. Once out on the pavement (wet, but terra firma) I was able to duplicate the same scenario in all gears including reverse. I never put the truck in Park.


I switched off the lights (it was twilight and cloudy so the low beams were on), no change in the behavior (several iterations). I turned on the lights and turned them on to High Beam (I have the High/Low on Mod) and the same behavior. Next I shifted out of 4 High to 2 wheel drive - 1 thru 6 again in Drive, 3, 2, 1, & R but only for a few iterations, then as quickly as this all started, it stopped!! :( Truck now behaves normal. Censored
<O:p</O:p

I cannot make it do it again. Whole time spent on this issue was about 10 -13 minutes. -:t BTW with the headlights on Low beam the PRND indicator is still flickering, but not with the HIGH/LOW beams on.

I replaced the NBSU unit shortly after I bought the truck a few years ago (it’s an '02) and the Chevy House was eager to oblige, especially after I showed them some of the threads from this site about water and the old NBSU versions and my extended warranty. I basically asked to have them fix it now or tow me later, and they agreed. I have been through a lot more water than tonight many times in the past with no issues, but the NBSU is the first thing that comes to my mind.

Any other ideas? Any questions, fire away.

The rain is still coming and except for this issue, I am loving it! :D

Nsbu.....

Thanks Eric, I think so too. Next call to the Cheby House!

I agree with Eric. I would still check fluid level. Here goes my broken record; " Scan It For Codes" if possible and post them.
mike

nsbu switch, mine acted crazy when it was bad, doors locking and unlocking, radio turn off, and only reverse no forward gears. i would bet on it.

Go to an Allison dealer or parts center. It will save you a good chunk of change and if they are a service center for the LCT 1000 series they'll change it for you too. (Of course labor charges apply. Better part, less money...

Or, invite Mike L. out for a steak and beer. I'm sure he'll do house calls. ):h

Eric & others, Teh Dmax is at the Cheby Dealer today for loss of brakes/pwer steering (getting PS pump replaced) and the steering shaft replaced for the rattle, the transmission issue comes next. Since I only that 44K on the rig right now, shouldnt the NBSU fall under the 100K drivetrain warranty? Not that its a big issue cuz I got the GM extended warranty.

All,

My duramax has 51,000 and I just had my NSBU replaced this week. I figured since I was beyond the 3 yr/ 36000 mile warranty I would have to pay out of pocket.

I took it to a large Chev dealer and he charged me nearly $300 to change it. Irritated with the price, I called a different chev dealer 30 miles away to see if they could have done better and their service dept mgr said it was covered under the emissions policy (who knows why it would be under emissions) and therefore covered until 100,000 miles. When I called back the dealer that replaced it he denied it at first, then went to look it up and sure enough, - IT IS COVERED. He said he certifies every year with GM and would have missed that test question and would have never guessed it be covered under the emissions policy.

So they credited back my card and submitted it to GM. They have changed alot of them for several years now and charged everyone whose 3/36000 warranty was expired, so they are going to have to go back and try to reimburse plenty of people.

My guess, is that many if not most dealerships overlook this as a warranteed item. If you paid for it and were under 100,000 miles I would be going back to the dealership for money back.

Got the Dmax back on Monday from the dealer (sorry for the late response!). While it was there I had them address the loss of steering and brakes, the steering clunk, the tailgate cable recall, and the transmission issue.

1. replaced the PS pump for low pressure ($100 deductable on the GM extended warranty... 44K+ on truck)
2. ordered the steering shaft (the greasing is not covered on the warranty, "so we'll replace it, that way its no cost to you when it comes in. Since it was investigated on this visit, there will not be another deductable to meet." Sweeeet!)
3. Cables installed
4. Could not duplicate the transmission issue, did notice a "low voltage" code. Tightened the battery cables (evidently one of the ground cables were loose from when I replaced the batteries about a month ago - I did notice that the engine didn't spin as fast as I thought it should, now it does).

Has anyone ever noticed a low voltage issue causing transmission issues? Some of the logic falls in place (low voltage influencing the TCM) but something just doesn't gel with me on thier diagnosis....