NSBU switch install??

[KrazyNate]

Well, my switch failed.. Im pretty pissed that I spent 27,000 dollars on a truck that I cant keep out of the shop.. Top it off with a WORTHLESS warranty and an as worthless dealer, you have a pissed off guy...... ME....

So, Ive poked around a bit and found some good info... Heard I can get the part directly from Allison for about 40% the cost of the SAME part from GM... Just curious how tough for an install??

Any and all help is appreciated

[More Power]

There's lots of info here in this forum that explains how to R&R the NSBU switch. We also have an illustrated online guide to replacing the NSBU in the subscriber section.

Jim

[77TransAm]

As you said, there's lots of info in the archives here, or just read Jim's article in the subscriber section.

Here's a reply I posted in a thread some time ago: NSBU install tips?

Let's see....
- You'll be putting the truck in neutral, so make sure you take the appropriate precautions when you raise it (wheels blocked, etc).
- If the connectors don't pull off easily, take the hair dryer out and warm them up - the potting sometimes melts in the old style NSBU's and the heat will loosen it enough to get the connectors out.
- Disconnect the shift cable BEFORE you try to loosen the nut on the selector shaft - otherwise you're looking at a broken shift cable. No fun to change.
- Once you have the nut and lever off the shaft, just pull the two bolts that hold the NSBU to the trans and finesse the NSBU off. It's a tight fit around the front driveshaft, but it will come out of there.
- Next, make sure the trans is in neutral (rotate the shaft all the way clockwise for park, then two clicks CCW for neutral. The flats on the shaft should line up with the little diagram cast into the trans).
- The new NSBU will have a small piece of stamped steel on it - that is to hold the switch in neutral. Leave that piece on the switch and install the switch onto the trans.
- Tighten the two bolts to 18-21 lb-ft, remove the stamped steel piece, install the new shield, the shift lever, and the nut.
- Tighten the nut to 15-20 lb-ft, install the cable, plug in the connectors, and you're done!

[Turbo Al]

A ten min job IF you want to clean out the mud behind the old switch.

[RochesterDmax]

Guys -
With 125k miles on my 2001 gmc sierra 2500HD (duramax), I suffered the dreaded NSBU
failure. Display was incorrect/missing on the PRND321, throwing codes (P1711, P1713,
P0700, P0847). Truck went into limp mode, drove 120 miles back home at 40 mph (2500 RPM). The information on this forum was excellent. So I thought I would add some info
from my experience with the fix.

Part cost varied tremendously:

- Mr. GoodWrench - $226
- Penn Detroit - $75 (local rochester place, authorized allison shop/parts)
- NAPA - $48

I ended up buying the part at the allison shop. Made by lucas, tan in color, part #29540479.
Hardest part of the repair was getting the electrical plugs off. Ended up breaking into the
old switch to get at the larger of the two connectors. Anyway, it appears to have fixed
the problem. I didn't see anything obviously wrong with the old part, so I did as they said
in the first Jaws movie, "a half-ass amateur autopsy". Here is a link to a picture of what
I found:

http://www.kodakgallery.com/ShareLan...localeid=en_US

Note the two areas where the contacts are corroded, they are circled in white. I live in
Rochester NY, and our vehicles are driven in a salt bath from November til April. Looks like
some got into the original part.

Guys thanks for the useful information, I am not sure what this repair costs at a gm garage,
but at ~$226 for the part, I am guessing north of $300 for it.

- Gary

[mikeintn68]

My 03 with 146K suffered the NSBU failure during a big snow storm. Thanks to these posts I was able to buy one on line from an Allison dealer for $91 and put it on myself. Saved me bigtime!

[Big Eric]

We had the same problem with our 2001 right after we bought it used. It had 103,000 miles on it and this truck also has only been driven in the salt belt. Ours went haywire when the roads were slushy. Thanks to this forum, we knew what it was and how to save a bundle of money. We plan on keeping an extra one on hand since we now know that the problem may likely return at some point.

[sooty]

I have a 2001 , 2500 HD with 70000 miles on it and wondering if I should just go ahead and replace the switch before it catches me on a outback expedition. Has there been a lot of failures on the new replacement switchs or are they improved and not failing as often?
Jim

[dr.olds]

What the hell is an NSBU???????????????? I still have trouble with this lingo!!!!!!!

[bobt]

neutral start backup switch
Bob

[dr.olds]

neutral start backup switch
Bob

What is its purpose?

[DmaxMaverick]

What is its purpose?

As the name implies, it prevents an engine start (starter engagement) if the range selector is in "gear" (neutral start), and controls the backup lamps (backup). Since the beginning of electronically controlled auto transmissions, it also indicates to the computer what is the actual range selection. It's a simple, non-logical, multi-position switch (although can be not-so-simple at times).

[Big Eric]

When they go bad, they make your truck act like it's taken over by Gremlins. Thank goodness they're simple to change. We're going to keep one on hand. You could probably make the change on the road if you carried simple tools and had a piece of cardboard or carpet to lay on.

[AE7JS]

There's lots of info here in this forum that explains how to R&R the NSBU switch. We also have an illustrated online guide to replacing the NSBU in the subscriber section.

Jim

Can't get access to the online guide to replacing the nsbu. HELP!

[jbplock]

Can't get access to the online guide to replacing the nsbu. HELP!

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