Overdrive or NV4500

[ptjsk]

Hello Guy's,

I have a '69 Dodge W300 with a 318, 4sp. and 488 gears.

I can barely get to 50 MPH.

I'm looking for suggestions on an overdrive unit, or a NV4500?

Thanks,

Pat

[Desoto61]

One of the biggest deciding factors would be the OD ratio. The NV4500 is 0.73:1 if I remember correctly. You can find any number of gear ratio calculators online that will show you road speed vs engine speed for just about any combination of gearing and tires.

An external OD would also let you split gears which can be helpful if you tow heavy loads, but packaging is usually the hard part of these, especially if 4WD.

[Hobcobble]

There have been others who put an NV4500 in their Sweptline.
You might also think about a bit taller tire. Them, with the O.D.
tranny, should get you down into the low 3000s or high 2000s?
I have a '68 W200 with the LA318/NP435 with 4.88s. It does
scream pretty good at 55mph.
John

[ptjsk]

Yes, I'm removing the 31" tall tires and replacing them with 35" tires.

They are supposed to arrived tomorrow (05/13/2014).

That will help a little bit, but probably not enough.

Thanks,

Pat

[Kaegi]

tires

jumping to 35s will make a big difference. but running 60 to 65 even with the 31s is no problem. the rpms come in around 2800 to 3000 which is perfectly acceptable. I have towed tons with d300s with 4.88s and 7.50 x 16 tires and the sweet spot for the 318 is about 62 mph. the slant 6 about 55 mph. with 35s can go 70 with ease.

[Aaron S]

The big issue with both modern overdrive transmissions and add on overdrives is length and driveline angle.

Using a two wheel drive NV4500 with your divorced transfer case will be tricky, because it is so much longer than the NP420/435 that the trucks are designed around. Since the transfer case is mounted lower than the transmission, the swap would likely require (at minimum) a custom prop shaft with CV joints. If that will do it, this would be the easiest route to take. If that won't do it, modifications to the transmission mounts to lower the tail end of the transmission would be necessary (or raising the transfer case, which comes with its own set of similar problems).

Using a four wheel drive NV4500 with a married transfer case would seem to be simple, except that many of the modern t-cases attached to these transmissions drop the front axle drive on the opposite side from our trucks. You would have to find a compatible transfer case and then have drive shafts built. Again CV joints will likely be necessary due to the angle and a crossmember would need to be fabricated to support the transfer case.

An add on overdrive would be nice, but most of them are fairly long and need to mount behind the transfer case. This creates driveline angle weirdness at the back axle (but at least you only have one driveshaft to worry about). You must remember to disengage the unit before engaging the front axle, or you will have two axles spinning at two different speeds. This will cause problems.

The Advanced Adapters Ranger overdrive would seem to be the answer. It is only about six inches long, quite strong, and mounts between the engine and transmission so you can split any gear in two or four wheel drive. The only problem here is that (the last time I checked) they do not build one for a Dodge application... if they did I would probably have one.

I have heard tales of a few of these trucks that have been outfitted with three speed auxiliary transmissions, which I find fascinating as I would love to be able to shift gears six times on my way through an intersection after a stop light. Unfortunately I have never had the opportunity to examine one of these trucks so I have no idea how these units were shoehorned in there.

Anything is possible with enough time, effort, and ingenuity (and money). It all sort of boils down to how badly you want what you want.

Another thing to consider (which I have personally encountered) is changing tires or gears or whatever, only to find you have made the problem worse because the engine simply doesn't have the power to get out of its own way. Our W300s are big trucks and were not really built to go down the road at more than 45 or 50 miles an hour. If you want to run with modern highway traffic, a built engine might do you more good than more gears.

[Desoto61]

It may be blasphemous to say but the Chevy versions of the 2WD (at least the very early ones) were much shorter than the Dodge 2WD versions. It might still be too long with your engine in the stock location, but it's something to look at, it's what I'm using with my conversion.

The benefit is that the cases for the later Chevy and Dodge versions were the same, so you should be able to create a hybrid with the Dodge input and adapter and the Chevy case or similar.

I know you can get a Dodge 4WD NV4500/NP205 that drops to the passenger side, Paul (in NY) has used this setup behind his 4BTs in (I think) all but one of his builds.

The Spicer 3153 might be another option. The stock OD is kind of high at 0.79:1 but once upon a time you could get a 0.69:1 OD gear to upgrade them. Charles Talbert uses these behind his diesel conversions with the stock transfer case, but again that's with the ability to move the engine, and even then a new intermediate shaft is usually needed either way.

[exline]

I don't know how it would work with 4WD but I just installed an A833 overdrive 4 speed from an 83 dodge truck into my 68 D100 and it was not very difficult. These transmissions are usually cheap. I run a 318 and it works very well for me.
I did think of doing an nv4500 conversion but it was going to cost me a lot more money.

[ptjsk]

Thanks for the information guys!

What do you guy's think about just changing my gears out to 411's? Or even 373's?

Thanks,

Pat

[Kaegi]

Thanks for the information guys!

What do you guy's think about just changing my gears out to 411's? Or even 373's?

Thanks,

Pat

me personally I love 4.88s. that is the same gearing as many medium duty trucks. I can tow and get good mileage and pull hills great. if I want taller in a 1 ton I could go buy a chevy or ford. but then towing capacity is wimpy. 4.11s to me are for big blocks or diesels.

[Desoto61]

The tradeoff there is torque vs. speed. There is a balancing act between the two. Too tall a ratio and you won't have the power you need to hold the higher speeds, you also loose some tow/haul capability, and acceleration times will drop. It's basically the same effect as adding bigger tires.

Either way, your best bet is to look at the power band of your engine, and find a good gear calculator online and play with the numbers. The transmission is harder but usually the better route because you keep the current performance characteristics for the most part but add an extra gear or two where you need them. Everything else is just trading power for speed.

[exline]

I have tried different gears with my truck and different tires but there is always a trade off and I was never really happy with it, the only real answer for me was an overdrive transmission. now I have the bottom end torque that I always had and also I have overdrive so I can drive on the interstate and keep up with traffic with out my truck sounding like it is going to blow up.

[ptjsk]

Yea....you guy's are right.

I really like the power and torque I have with the 488's.

Like the saying goes, doing the right thing isn't always the easiest, and in this case a type of overdrive unit, or transmission change is the way to go!

Thanks again for the reply's!!

[CO Gary]

Ranger overdrive

It goes between the bell and tranny. here is so info from some years ago about putting it in a Dodge. A W300 has enough room for it and you can split shift with it. They may have a Dodge version by now. Gar

The Ranger Overdrive is seven inches long. Advance Adapters makes the
Ranger with front faces for the modern Dodges with the 5.125" bell housing
index with 1"x23 spline shaft but not the older Dodges. Other front
ends for Ranges include GM with 4.486" or 5.125" index with 1-1/8"x10 spline,
Ford 4.484" or 5.125" with 1-1/16"x10 spline. My deal with them is for
GM front ends with the 5.125" index with a rear end that is set up for the
older Dodge 1"x10 spline input shaft and a 4.75" diameter bearing retainer.
They are not drilling the transmission mounting holes in the rear face of
the overdrive in order that they can be drilled at a local shop to match the
transmission actually used.

To put one of these between a motor using something other than a Chevy
bellhousing and the stock transmission: Enlarge the index hole in the
bellhousing to 5.125" to fit the Ranger Overdrive. Drill new mounting
holes in the bellhousing to match the Overdrive or vise versa. Change the
clutch so that you have one that is compatible with the input shaft used
on the Ranger (in my case the 1-1/8"x10 spline). Use an extended pilot
bushing since the input shaft on the Ranger is a bit short. Trim off the
excess length on the input shaft of the stock transmission so that it will
fit properly into the Ranger.

To the best of my knowledge, Advance Adapters has discontinued making the
electric shift Ranger Overdrive, so plan on adding another shift lever...

The Ranger is available in both Overdrive and Underdrive versions. The
Overdrive is a 27% overdrive; the Underdrive is a 17% underdrive.



http://shop.broncograveyard.com/Rang...YB8hoCnYTw_wcB