NV4500 = Crap???
 

I have been contemplating a 5-speed in my ’69 K10 for quite some time now. I used to be certain that I was going to use an NV4500…

All I see is how strong and wonderful the NV4500 is. Four wheel drive magazines sing it’s praises, so does everyone else, but I can’t ignore my own observations.

Case #1. My brother’s ’94 light-duty (six-lug) K2500 Chevy 350ci. NV4500 started to die at about 240,000 miles. Completely died at 250,000 miles.

Case #2. My best friend’s ’92 K3500 dually 454ci. Bought the pickup at about 45000 miles, about 2000 miles later, NV4500 started making noise. Been VERY noisy ever since, hard to shift, pops out of gear sometimes.

Case #3. My Dad’s ’94 Dodge ¾ ton 4 wheel drive w/ a Cummins. 130,000 miles, NV4500 dies (well, 4th gear worked, but none of the others).

Case #4. The NEW replacement NV4500 that my dad put in his ’94 Dodge Cummins. 5th gear decided not to work. We took it back, they said that a retaining nut backed off, and they tack welded it to make sure it didn’t do it again. A few days later, 5th stopped working again. Took it back, this time, they put a nice full bead on the nut. Not sure how the tranny is behaving at the moment…

Now, before you guys start saying things like “It was 240,000 miles”, how about my SM465 in my ’69 that has over 300,000 miles, or the Getrag 360 in my ’89 Dodge ¾ 4-wheel drive with 450,000 miles & a Cummins that has at least 150,000 miles with a heavy trailer behind it. And before you start saying, “It was behind a Cummins, or a 454”, see above note about the Getrag. Yes, the Getrag needs rebuilt, bad (synchros are shot), but it still shifts, still has ALL gears available, and doesn’t make much noise.

Am I wrong? What’s the deal with the NV4500?

Anyone used something BESIDES an NV4500 for their 5-speed swap (four wheel drive)??

Any thoughts on the subject?

Well, I wouldn't say it's crap. It can have a few problems here and there without being crap. :)

The retaining nut backing off is actually a common problem among NV4500s, so chalk that one up to poor design, and expect that it could happen to any NV4500.

Maybe you left the following details out because they weren't a factor in any of these cases (and I'm not trying to insult your family's or friend's intelligence), but I'd be curious to know if the lube levels were up, and if everyone, including the previous owners, used the correct synthetic lube. Was the Cummins chipped? There's so many different reasons why a tranny can go out and I'd have to know more before I would say that the NV4500 is a bad tranny. :)

I was contemplating swapping a Clark 5-speed transmission from a medium duty truck. However, I know no one who has done anything remotely like this. There was an article about Clark 5 speed OD truck trannies a few years back in 4WOR, but I don't remember much about it. A few truck suppliers sell the tranny, but, again, I haven't really heard much of anything about it. It is supposed to be tough as nails (used in med trucks), shifts like a truck manual tranny (big & clunky shifts), but with a granny low and OD 5th.

This is all I know about Clarks:
"Not all Clarks have Overdrive, in fact there are only a few. All Clark overdrive model numbers end in VO. There is the 200VO (6.06, 3.50, 1.91, 1.00, 0.80, R-4.87), the 204VO/205VO (6.06, 3.50, 1.91, 1.00, 0.80, R-6.00) the 207VO/251VO/264VO (6.06, 3.50, 1.80, 1.00, 0.80, R-6.00), the 280VO (5.98, 3.50, 1.86, 1.00, 0.80, R-5.04), the 280VOHD (6.17, 3.48, 1.85, 1.00, 0.80, R-6.27), the 300VO/307VO (6.27, 3.51, 1.89, 1.00, 0.80, R-6.27), the 380VO (6.27, 3.55, 1.89, 1.00, 0.80, R-5.11), and the 400VO/408VO (6.17, 3.56, 1.90, 1.00, 0.80, R-6.02). As the numbers increase so will the torque rating (280VO is rated for 330 ft-lbs and the 400VO is rated at 405 ft-lbs)."

Don't remember where I found this.

I do know that a friend of mine bought/cleared some land, and on this land were 3 International crewcabs, and they each had Clarks and divorced Tcases and Dana70's front and rear. And he won't sell.

On the '94 K2500, yes, by brother is anal about maintenance. Fluid levels were fine, and it was the correct synthetic. On my dad's Dodge, yes, he's not anal, but he doesn't like to pay for repairs, so he makes sure it's done. It did have the correct synthetic, and the levels were right... on both his trannys.

On my friend's '92, I know for a fact that he uses 90w (non-synthetic) with moreys, and I'd bet $100 it has been and always will be overfilled. I try to tell him different and he don't care! Maybe he's on to something, since his is only making noise and hasn't grenaded...

Oh, No chips in my brother's or my dad's.

There is a chip in my friend's 454, but his is holding together.

I had thought about 5-speeds from older medium duty trucks, but I discovered, as Duallie did, that most aren't overdrive.

Just think about this... Nearly everbody that is running a Jeep/ect off-road is running a NV-4500, if they have a manual tranny.

Just like GMCBLU said, the retaining nut is just a flaw in the design.

Everywhere I read, people say to stick an extra quart of lube in it. The Dodge board TDR has a few threads about the NV4500, and they say to run it a quart over... AND a lot of the guys on that board and turning some big torque #'s!

I think if you looked at NV4500 and Gertrag problems in like vehicles, 3/4 and 1 tons, the NV4500 shines. The NV4500 does have a reputation for being a little noisy at road speed. I think Advance Adapter even runs noise test on theirs before selling them. All in all I still think the NV4500 is the best choice, and that's what I put in mine.

I looked into a 5 speed myself and decided to go with a non overdrive unit as they are stronger. If you run a slightly higher gear set, you get about the same high gear results. Depending on the tranny you choose, you can have the same (or close) low gear results. I decided on a NP542, of which there are quite a few to choose from. They were made for almost all US built of Light commercial trucks, (like bobtail dumps with 20 inch duals) but the best Chevy version was commonly in a school bus. I am using a divorced t-case, so I can get away with a bit more stuff without having a custom built adapter. Pricewise, the 542 is generally cheaper than a NV4500 as nobody really knows what the heck they are. Parts seem to be available and they are strong as heck.

I haven't done anything about actually buying one, but a guy here in town has one behind a cranked up 503 (which he claims will pass a powerstroke like it up on jacks) and he pulls big hay trailers all over the place with no tranny problems. He tried a Clark and said it Was Crap

Just a little side dish for the discussion.

Good luck

What is to be done about the retaining nut? If it's a known flaw in the design, there should be a fix that doesn't involve a welder...

I'll check out that Dodge board.