Transfer Case Operation

[CJ Johansson]

OK folks, I understand completely why, when you turn tightly in 4WD, you get that occasional slip of the tires on the gravel (no front-to-back differential action).



So, what I would like to understand is, with these Center Axle Disconnect front axles we have, why does it still seem to do the slip thing AFTER you shift it to 2WD, but before the 4x4 light goes out (CAD disconnects) Sure, at this point you still have the CAD connected, but the transfer case should be disconnected, right? Thereby allowing front and rear drive shafts to turn independently, right?



Or is it just that only MY truck does this, cause there's something else wrong???



-cj

 

[grtescpa]

Originally posted by CJ Johansson

OK folks, I understand completely why, when you turn tightly in 4WD, you get that occasional slip of the tires on the gravel (no front-to-back differential action).



So, what I would like to understand is, with these Center Axle Disconnect front axles we have, why does it still seem to do the slip thing AFTER you shift it to 2WD, but before the 4x4 light goes out (CAD disconnects) Sure, at this point you still have the CAD connected, but the transfer case should be disconnected, right? Thereby allowing front and rear drive shafts to turn independently, right?



Or is it just that only MY truck does this, cause there's something else wrong???



-cj

Your not alone with this problem. My Dodge ram

when shifted into 4 wheel takes a moment or two to engage the front axle. There has to be some forward or reverse motion or it just won't engage. If your to qiuck on the throttle it bangs in like a hammer. My tires will drag on gravel and sandy hard surfaces in tight turns. I think thats normal in 4x4 but it may be the fact that the front axle has not fully disengaged from the wheels while Going back to 2wheel. Mine Needs motion again and the 4x4 light stays on even when the transfer case is back to 2x4. All this can be a bit frustrating when your stuck with the rear wheels spinning. The use of Amsoil in the front axle has improved the delay but its still a pain. Its for this reason I wish that I could install manual locking hubs. You have to change the entire front axle to accomplish it. Big Bucks!!

 

[CJ Johansson]

Hey grtescpa,



Thanks for the reply, but I'm not sure you got my point, exactly. The delay is, well, annoying, but normal due to the vacuum operation, etc. You're right, you need some motion to engage/disengage.



What bothers me is that, during that delay period, before the CAD disengages, but you've shifted the T-case to 2WD, you still (well, I do anyway) seem to get that dragging/hopping effect in a turn. Maybe it's more just the feel in the steering wheel, but it sure feels like the thing's still in 4x4.



Sure, the axle is connected, so you're spinning the whole diff, all the way up to and including the front drive shaft. But, since you've shifted the T-case, the upper end of the drive shaft should be free to spin as it pleases, regardless of what the rear shaft is doing. So, why does it still have that hop/skip feeling? My (oh, should I say this?, uhh, here goes... ) Ford (there, that wasn't too bad) pickup doesn't do this, even if I leave the hubs locked.



I'm with you though, I sure wish I could get manual locking front hubs without having to mortgage something else for the big $$...



-cj

 

[Texas Diesel]

since there ie no center differential, driving in 4wd creates slightly different loads front / rear. This is why it says not to run in 4wd on dry pavement ( turning makes it much worse ). When you shift back to 2wd the transfer case AND the front axle will not release until the driveline load front/rear is eased. My 95 Dakota does exactly the same thing. My 2001 does it too. It is perfectly normal.

 

[CJ Johansson]

Thanks Texas,

Well, if that's the case, it makes sense then. I've never had one of these apart, so I don't really know what the guts look like. I kinda figured it was more like a regular transmission so when you shifted the lever it would actually disengage the gears. But, considering that it's designed to be shifted without the clutch (well, kinda anyway), it makes sense that the shift lever is only loosly coupled to the mechanism and not actually moving things directly.



Still doesn't explain why the Ford doesn't do it, it's designed to shift on the fly too, maybe it has something to do with having an auto transmission on that one...



-cj