Nv4500

[BoatDriver]

Truck in question is a 1994 K2500. Vehicle was on cruise, 70 MPH, towing an empty car hauling trailer.
Started hearing a buzz, at first I thought it was the radio, leaving city, thought it was radio fade.
Turned off the radio, guy with me said, "What's that?"
Then a loud BANG, vehicle felt like it was running over road serrations (zip stripes in the pavement at toll booths to wake a driver up).
Whipped the clutch in, coasted to the emergency lane.
Tried to move the truck in low gear. Engine lugged down to stall. Tried first gear, same result.
Only gear operational is third. All other gears now out, just engine revs, no movement of truck with clutch engaged.
At first I thought I'd overhaul the trans myself, I used to rebuild Ford toploader transmissions years ago at the street/strip.
After researching this trans, I find out the output shaft has been redesigned, and internal components have to be inspected/replaced at overhaul, making an overhauled trans more affordable. Used to be, synchrones and gaskets, you were good to go.
I haven't had time to pull the trans yet.
Anybody familiar with this trans. What fell apart in this trans.

[Turbo Al]

Since 1993 this would be the first Chev NV4500 that I have heard of that blew up. Dodges blow them up on the hopped up Cummins once in a while.

Some web sites for more info,
www.JBConversions.com
www.newventuregear.com
www.high-impact.net
www.advanceadapters.com

If you did blow the trans you will know it by pulling the trans shifter and or the inspection plate (not all have the inspection plate) and finding various pieces in the wrong place. I strongly believe your pressure plate (or clutch)let go if you had been pulling bob tail for any amount of time -- I can't see the trans going unless it was just pulling a lot of weight just previously to dieing or was very low on oil. It is also possible your flywheel came apart but not too likely.
The Chevy and Dodge NV4500 (NV = New venture) are NOT interchangeable, and the model year of your truck has the rare low gear ratio which is much in demand by the off road crowd.

Good luck

Al

[BoatDriver]

Clutch works just fine, in third gear only, so the flywheel/pressure plate isn't going to to be the problem. Was pulling enpty car hauler 2000 LBS. at best.

[JohnC]

Not up on the specifics of the NV4500, but if it binds up in all gears except 3rd, then it's likely 3rd is somehow permanently engaged. Will it drive forward in neutral?

[Inspector]

Sounds like a rebuild is in your future. We just did one in the 93 last year. It was an output shaft problem as it would slip in the splines of the transfer case. Also had to replace the planetary in the Tcase. While it was apart the input gear showed abnormal wear and had to be replaced. The syncro clutchs were worn so did them as well. It was a pretty big bill but was worth it. Smooth as glass now. I would also suggest doing the clutch, pressure plate, through out bearing and pilot bearing while it is out. The tranny is a heavy ol bugger. Don't forget to have the flywheel surfaced.
One important item, the oil for NV4500 is specific and only available from GM. It is called __Syn-Torque__. It is a must to use this oil. If it didn't have the syncro clutches it probably wouldn't make difference.
Denny

[HH]

If you like to do it yourself, you could try this place http://www.quad4x4.com/ - I have never used them but am considering it because my 4500 is grinding into 2rd gear (L,1,2,3,od). They were very helpful on the phone and IIRC a rebuild kit comes with a how to video.

While you have it apart, make sure your pilot bearing is good and check the throwout fork pivot stud and fork for wear, may be a good time to change all.

I had the 4500 redone about 5 years ago, and it was about $800.00, I pulled it and brought into the shop. Story for another day, but I will never use them again, that is why I am considering again rebuilding the 4500 myself.