All Time Four-Wheel Drive?

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February 25th, 2014, 03:02 AM
DeanJohnson

All Time Four-Wheel Drive?

So, I used the search function for an hour and could not find an answer to my question...

I met with my builder the other day and he showed me my NV4500 transmission bolted to some sort of old overdrive unit. He explained that once it was installed I would have a high, neutral, and low gears.

I didn't realize what he was saying until later. I think what he was saying is that my truck will only have 4WD. I know he/we have been searching for an easy solution to the stock low-gearing. But, I don't know if this is OK.

Will it be OK for my truck to be 4WD all the time? I would worry about fuel economy, but on some level I think the range of gears will help me keep my RPMs down.

What do you think?
February 25th, 2014, 06:57 AM
ray steadward

That sounds like a regular 2 speed transfer case.....Unless there is still a T-case to go behind that? Did the O/D unit have 2 outputs for driveshafts on it?
February 26th, 2014, 05:41 PM
DeanJohnson

All Time Four-Wheel Drive?

I saw my guy again today. I asked him: "So, it's a two speed transfer case?" He told me "Yeah, it's the one everyone wants, it's worth a lot of money."

I took some pictures while I was there.

So, does this mean I am 4-wheeling all the time? Is that OK?

http://imagizer.imageshack.us/v2/xq90/542/57zd.jpg

http://imagizer.imageshack.us/v2/xq90/842/zoud.jpg

http://imagizer.imageshack.us/v2/xq90/824/vrh6.jpg
February 26th, 2014, 05:54 PM
jeepdriver99

In the first picture, see the little round white/silver tag with the red ring? That should tell you the model of the transfer case. It should be easy to look up on the net.
February 26th, 2014, 06:00 PM
Barrman

That looks like a passenger side drop NP208 or 241. There is a number inside the red data plate. Get that number. Chain drive, aluminum case. That is not a full time all wheel drive unit unless I am missing something.

Why do you want all wheel drive on the street? It will make a lot of drag and wear out stuff faster than a normal 4 wheel drive when you want it on soft surfaces.

By the way, most everybody seems to want NP205 cases because they are cast iron, gear drive, PTO drive port and pretty much bullet proof. The aluminum chain drive units are more prone to cracking and have shift fork bushings that wear out and need to be torn down completely to fix.

Just asking. It is your truck and do as you wish.
February 26th, 2014, 06:42 PM
DeanJohnson

2-Speed Transfer Case

Next time I am there I will get the number from the data plate. My guy said this is the solution to my gearing. (Gears too low to drive on the highway.)

I would rather have a NP205, but then I have to swap axles, or gears...

But if I've got it right, I will be in two wheel drive (with the transfer case
in neutral) and then either 4-high, or 4-low. So, I won't be 4-wheel drive all the time. But this will only help me if I put int in 4-high when I want to cruise down the highway.

I wont' be driving on the highway much, and when I do, I won't be making any sharp turns. So, it seems like an OK plan to me. He likes it because its married, instead of divorced. If I want him to change it, I have to have to be able to tell him why.
February 26th, 2014, 10:57 PM
Mikel

Quote:

Originally Posted by DeanJohnson

Next time I am there I will get the number from the data plate. My guy said this is the solution to my gearing. (Gears too low to drive on the highway.)

I would rather have a NP205, but then I have to swap axles, or gears...

But if I've got it right, I will be in two wheel drive (with the transfer case
in neutral) and then either 4-high, or 4-low. So, I won't be 4-wheel drive all the time. But this will only help me if I put int in 4-high when I want to cruise down the highway.

I wont' be driving on the highway much, and when I do, I won't be making any sharp turns. So, it seems like an OK plan to me. He likes it because its married, instead of divorced. If I want him to change it, I have to have to be able to tell him why.

Nothing wrong with a NP241. Barrman is right about the NP205 being more robust, but the vast majority of NP241s go to the junkyard being operational. I wouldn't sweat it. Besides, you get a better low range.
February 26th, 2014, 11:10 PM
Barrman

Maybe I am just being dense tonight or something. But things just aren't adding up for me. I see the red NV4500, I see the aluminum housing at the back for 5th gear which is also the cross member mount and the t-case mount. Then I see a transfer case with a long tail slip yoke. Where is the other drive?

A NP208 or what I think you have, NP241 has 4 selections: 2 hi which just drives the rear axle, 4 hi which drives both axles at the same speed as the input from the transmission, neutral which lets nothing be driven by the engine and 4 low which drives both front and rear drive shafts at 2.?? times less than normal. There are no other options that I can figure out.

Normal driving will be in 2 hi and it will behave just like any other rear wheel drive vehicle.

I'm not trying to pick on you. I am just trying to figure out what is unique about this set up.
February 27th, 2014, 12:09 AM
Mikel

I think the confusion came from the two speed transfer case. I too expected an overdrive like a Ranger or Brownie.
February 27th, 2014, 12:22 AM
kwai

that configuration will improve your highway speed in 5th gear. In 2 hi (or 4 hi) the gear ratio through the tcase is still 1:1. The overdrive in the nv4500 will help on the highway speeds with a ratio 0f 0.73:1. 4th gear is a 1:1 ratio.
February 28th, 2014, 12:55 AM
DeanJohnson

Low gears

So, I'm not sure I am worthy of owning an M715. I have so much to learn. Thanks so much everyone for being patient with me. I now understand how a transfer case works. I told my mechanic all about my worries about the stock M715 gears being too low. I think he is using the NP241 because he already had it and doesn't like divorced transfer cases. But, I think it will fine, and I don't plan on getting stuck anywhere with 2.7x:1

http://imagizer.imageshack.us/v2/xq90/841/t36r.jpg
February 28th, 2014, 01:09 PM
Barrman

That 241 will do you good.

Don't worry about being worthy. We all had to learn sometime and are all still learning.
February 28th, 2014, 02:29 PM
jeeper

Quote:

Originally Posted by DeanJohnson

But, I think it will fine, and I don't plan on getting stuck anywhere with 2.7x:1

The main reason people get stuck is because they don't have traction. It is possible to get stuck while you do have traction, but that is less common.

The 2.7:1 won't give you any additional traction. It will give you more power to the wheels.

You can think of it like a ten speed bike. When you are in a high gear it pedals pretty hard but allows you to go fast. When you are in a low gear it pedals easy but goes slow.

When you put your transfer case into 4lo you are not only engaging the front axle for 4wd, but you are also shifting it into a lower gear.

While you are in 4lo you are putting less stress on the engine and transmission but you are putting more stress on the drive shafts and axles. The lower gears are multiplying the torque from the engine.

I would be happy to have that set up in my truck. I don't have over drive and am starting to wish I did. I pretty much can't go highway speeds in my truck.