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Had to use 4-low to get out of 3" of snow/ice?

3K views 46 replies 10 participants last post by  steve_80 
#1 ·
Hm, yesterday when I left work, I was spinning in 4-High, didn't even put the gas on. (using 1 year old Defender LTX M/S tires)

Put it in 4-Low, and no problem.

It was only about 3" of snow with packed snow/ice underneath.

Co-worker in-front of me got out no problem in his Mercedes B200 (2WD), same snow/ice under him.

Is.... that normal? lol
 
#2 ·
It sounds like the progressive coupler in your NV247 is bad.
 
#5 ·
As your wheel speed differs between the front and rear, the Progressive Coupler in the 247 applies torque to the front. The greater difference in wheel speed, the more torque the PC applies, allowing the wheels to turn at the same rate. When the PC goes bad, it can no longer apply the necessary torque to the front when your rear wheels spin. Locking your transfer case into 4LO bypasses the PC. Since yours works in 4LO, it's likely that the PC is bad.
 
#7 ·
steve_80 said:
well that doesn't sound cheap to fix at all... I had it up on a lift a few months ago, and all 4 wheels spun in 4-high. But in the summer I did have to use 4-low to reverse up a hill since 4-high spun only 2 wheels.
On a lift isn't really a valid test. I posted something about this in another thread recently. I have a (working) 247 sitting in my basement and it has no fluid in it (fluid is required for the PC to work, it uses a pump to clamp the clutch plates). It will still turn both front and rear outputs in 4hi when you spin the input shaft. If you actually give it some resistance though, it will only spin the rear. So with little or no resistance (all wheels off the ground) the 247 can still spin all your wheels even when the PC isn't doing anything. Once there is resistance, the pump needs to pump and the clutches need to engage enough to overcome it.
 
#9 ·
steve_80 said:
Ah, that makes sense. I will check the fluid when I get home. I know that it was full a few months ago, and there's no leaks, but you never know. Is replacing the entire transfer case the only fix?
You can replace just the coupler for around $400 for the part. You may or may not be able to get an entire transfer case in better shape than yours for that much.
 
#11 ·
Also make sure you are using the correct fluid in your T-case, regular ATF will cause it to fail.
 
#16 ·
Call your local junk yard or even try ebay if you want to just change the t-case. I had found some really cheap select-able t-case's that you wouldn't even have to worry about the "automatic" 4x4 system. Bolts right in, just have to make sure you realize you will have to "shift" it into 4wheel drive.

of for close to 300 bucks on ebay
http://www.ebay.com/itm/Transfer-Ca...ash=item2ee1d71ee8:g:xkoAAOSwpdpVY7io&vxp=mtr
 
#20 ·
Personally, I'd "upgrade" to the NV242, though I'll admit would be more work and time involved.

Being that a direct NV247 swap would be quick and easy, that's a great way to go if the price is right.
 
#25 ·
The issue with the 247 is the progressive coupler; the 242 doesn't have one.

The 247 needs a Mopar specific fluid, the 242 uses ATF

Problem with most of the 247's is whether the previous owner used the correct fluid.

I would be in the same spot if I planned to keep a 247 that was having issues.... put in a new coupler and maybe a chain and the correct fluid and it will live another 200K.
 
#24 ·
steve_80 said:
Is the 247 known to be crap? Why would a junkyard 247 be potentially worse than a junkyard 242?
The progressive coupler has clutches, clutches are a wear item. The 242 doesn't have those. So a junkyard 247 may be just as worn as your current 247, while a 242 wouldn't be (assuming it didn't have other issues). I'm not saying the 247 is crap, I'm saying if I were to go to the trouble of replacing one, I would want the biggest wear item to be, well, not worn.
 
#30 ·
I just added 1/2 a bottle of Mopar NV247 Transfer Case Fluid... very odd since the shop just redid all of that and filled it. Yet there's no signs of leaks or anything wet on the transfer case.

Where else could it leak from on that thing? Does the fluid stay in the transfer case, or does it go elsewhere?

Could the low fluid have caused the issue of it not working? It was only 1/2 a bottle
 
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