As my '98 ages, I'm planning ahead for rebuilds and/or upgrades of the major powertrain components.

The engine will involve a stroker kit, but overall it will be a mild build, because I won't be able to practically use masses of power in a 1500 daily driver.
So for this discussion we'll say 350HP/400TQ (give or take).

The stock trans is the NV3500, good for ~310TQ (continuous).
I'm contemplating changing up to the NV4500 (DDP), good for ~410TQ.
The 92½-00 DDP (I think) has the same input shaft as the NV3500, and all V8 trans have the same bellhousing bolt pattern... so worst case would be a clutch plate swap and a bigger spigot bearing.
The output is 23 spline.

I have the 231HD transfer case, good for ~730TQ (continuous).
I like the idea of a 241OR (Wrangler Rubicon), good for ~1500TQ (continuous).
This has the same input and output spline count... it may be shorter shaft length(?).
The chain is 1½" wide (231HD is 1¼"), the same as the diesel/V10 version of the 241DHD.
It is also a 4:1 low range (which would be nice)... all the others are 2.72:1.
It's a beefier case (size and ribs), which might be a problem fitting in height wise... maybe space the crossmember down a little (ground clearance isn't a big concern for me).

The rear axle would be changed up to a Dana 60.
And I would have to do custom tailshafts... the 241OR has the SYE (slip yoke eliminator).

Other than dollars, what are your thoughts?... any other input?

PS... will get rid of the CAD with a one piece front axle.

 

Were it mine, I'd just go with the 231HD and call it good. There are two reasons for this: First, 400 ft/lbs of torque isn't going to damage the thing, ever, so there's no reason to go into overkill. First-and-a-half: You'll probably grind the NV4500 to dust before you break the NP231. Second, it's a ubiquitous piece with all kinds of options for parts no matter where you are in the lower 48 so trail/road trip breakdowns would suck less.

But, of course, if it were mine it would be built for the Rockies and sparsely populated regions of the West rather than South Florida, so my opinions aren't applicable to your world. But there they are anyway.

 

NV4500 would be a great upgrade. Look into the 5th gear nut issue though..... I seem to recall that being an issue. (or, something similar....)

D60's on the dodge trucks are all 8 lug. So, find a set of axles, and replace the front with a D60 as well.

Would the posi-lok for the front axle be cheaper/easier than the one-piece axle? Not sure if it would make any difference in wear parts, or fuel consumption......

What kind of off-roading do you do in Florida?

 

5th gear nut problem is a nut that backs off and the gear falls.
Front axle you could always slide the collar and flip the fork or buy a one piece axle. I'm opposed to the posi-lok myself.

 

Of all the vehicles that I added free-wheeling hubs to, I don't recall seeing any major fuel savings, and you inevitably had to get out in the mud to engage them.

Flipping the CAD fork, or using a CAD eliminator kit would be the cheap fix, but is the two piece axle a weak point?

I'm aware of the 5th gear retaining nut issue, and there are a couple of common fixes.
I like the idea of the lower 1st/2nd ratios in the NV4500.
Do they shift nicely like the NV3500, or is it a clunkier truck feel (being a bigger heavier box)?

There wont be any serious off-roading, but there might be some stump pulling, slightly over rated load towing (short distances), moments of hard acceleration, etc... so whilst building an overkill setup is not the real goal, I don't want to be doing rebuilds because of a foot slip on the peddle.
I'm closing on 200k with the stock setup... it would be good to do the same again (or at very least half that) with the new build components considering the increased power.

 

Well, the elimination of the hub/bearing feller is good for longevity.... I like rebuildable/replaceable bearings better in any event. Rumor has it, you can scavenge parts of 92-98? Ford 3/4 ton trucks.

I converted my old Blazer to part time 4wd, from full-time... I got 1 mpg better. That's it. Of course, going from 10, to 11, was a significant improvement.......

I use my truck to pull stumps, but, I let the weight of the truck yank 'em, not my driveline. Leave some slack in the chain, goose the gas, and before the chain hits, get off the gas. 6000 lbs of truck packs a wallop. Usually doesn't take more than three hits to get stumps about 2 feet in diameter out.

 

I got about 2MPG out of the part time/manual hub conversion of my '78 Cherokee with the QuadraTrac (Borg-Warner 1339). Along with maintainable bearings I also saw reduced tire wear, which was very, very nice. The two-wheel drive low range was handy every now and then, too.

 

With what you're doing....don't change a dang thing Spillage, unless something breaks. That's the best course really. See how that drivetrain holds up to the stroker kit so you can boast about breaking or that it all holds up plenty.

It's only a matter of time that you want to spin the wheels in some Florida mud....and !! UUUUUpp grades!!!

 

I hear that.
Problem is, it's a daily driver, so I have to minimize any down time... I save and accumulate parts, then do change outs over the weekend... I'm trying to avoid the untimely dropping of parts on the ground.

The strategic placing of the chain around the stump helps also.

 

NV4500s definitely shift like you would think a heavier duty truck should shift like. Just keep the nv3500, they are rated to 300 hp and imo an underrated trans.

that said.... a nv4500 definitely aint no old school np435.