Wheels dragging when making U turns in full-time

[jja]

It feels kinda like part-time. I can feel and hear different wheels getting stuck and dragging for a short while when I make an U turn in full-time. Then they'll get lose and then stuck again.

That's something that started happening recently. I changed the transfer box oil. Level was normal and there were no debris. There are no strange noises. It feels as if the central differential got really tight. Has this happened to anyone here?

 

[sota]

you sure it's in FT and not PT?
don't go by the indicator on the dash either.

 

[Aceofspades]

Does it do it in 2wd ? My front tires scuff when I make sharp turns low speed

 

[LibertyTC]

Even with full time, I would assume that there is a rotational difference between R&L tire in full hard over turns, especially noticeable on hard dry surfaces.- Normal.
When I am in part time I still make slow turns, but not hard all the way over turns, to keep binding at a minimal.

 

[tommudd]

It feels kinda like part-time. I can feel and hear different wheels getting stuck and dragging for a short while when I make an U turn in full-time. Then they'll get lose and then stuck again.

That's something that started happening recently. I changed the transfer box oil. Level was normal and there were no debris. There are no strange noises. It feels as if the central differential got really tight. Has this happened to anyone here?

Of course its going to do that

 

[HoosierJeeper]

Normal. My LR3 does it too in tight turns.

 

[ltd02]

Yep, My 02 would do it in sharp turns while in FT. Haven't done it in the 05 but I'm sure it would if I tried.

 

[jja]

I am pretty sure it's in FT when doing that. It's not like I just switched to it or something. It does not do it in 2wd.

Why would that be normal? I've driven other FT vehicles and I've never experienced this. That's what the center differential is supposed to take care of isn't it?

 

[HoosierJeeper]

It's not perfect

 

[jja]

I don't get it. What is not perfect?

 

[HoosierJeeper]

The full time system. It eliminates most of the binding, but you can still get some.

 

[jja]

The full time system. It eliminates most of the binding, but you can still get some.

That's weird. I think the NV 242 has a central differential. The differential should not bind. Where would the binding come from?

 

[HoosierJeeper]

That's weird. I think the NV 242 has a central differential. The differential should not bind. Where would the binding come from?

It does have a center differential. It doesn't bind under 99% of turns, but turn tight enough and it'll bind a little bit...it's not an electronic FWD setup like most new stuff. Mechanical stuff does mechanical things. :gr_grin: As I said, even my LR3 does it and it has a center diff too. My WK did it as well. As long as it's not binding like it's in 4 part time, it's normal.

 

[tommudd]

That's weird. I think the NV 242 has a central differential. The differential should not bind. Where would the binding come from?

You have a front and rear differential with a transfer case
You have all 4 wheels that are now are trying to turn at the same speed, BUT 2 are turning in a smaller circle ( inside ones, while the outside tires are taking a wider / longer path ) so of course there will be binding. The transfer case does not do anything but provide equal or near equal amounts of power to the front and rear diffs .

 

[HoosierJeeper]

You have a front and rear differential with a transfer case
You have all 4 wheels that are now are trying to turn at the same speed, BUT 2 are turning in a smaller circle ( inside ones, while the outside tires are taking a wider / longer path ) so of course there will be binding. The transfer case does not do anything but provide equal or near equal amounts of power to the front and rear diffs .

Plus another diff in the tcase (242) that allows the front/rear to rotate at different speeds, but as stated, nothing is perfect but it does reconcile most of the difference. In the 231 KJs the front/rear have to rotate at the same speed, no center diff to reconcile the difference.

 

[jja]

While it's comforting knowing that all KJs do that I still find it hard to believe that's how differentials should work. That means it should bind in 2wd to since front and rear differentials would also be compensating for speed difference in U turn. It does not bind in 2wd, though.

 

[HoosierJeeper]

It doesn't bind in 2WD since there isn't any power being applied to the front, they're just along for the ride. (front drive line is still spinning though)

 

[tjkj2002]

While it's comforting knowing that all KJs do that I still find it hard to believe that's how differentials should work. That means it should bind in 2wd to since front and rear differentials would also be compensating for speed difference in U turn. It does not bind in 2wd, though.

"Torque" is why you get binding in tight,slow turns in a KJ with the 242 t-case.

When torque is applied to the differential it naturally wants both axles(or front/rear drive shafts in the t-case) at the same speed,the spider gears have alot of force being applied to them that takes a second or two to overcome and even then has alot of resistance to letting the axles(or driveshafts) spin at different speeds.

Without torque being applied this will not happen and why you don't feel it while in 2wd since no power("torque") is being sent to the front diff and the center diff is not being used.The rear diff is being "dragged" and the wheel are not "steering" so that slight binding is not felt.

Plus the 242 t-case is setup to bias the front/rear torque split(48/52 if I remeber correctly) since the KJ uses mis-matched diffs(D30A front and 8.25 rear) which do not have the exact same gear ratio,the front diff will spin slightly faster then the rear by design.You don't want the rear end to spin faster which would make it uncontrollable trying to drive in a straight line in 4wd.

The 242 t-case is almost a 40 year old system so it's pretty crude compared to the weak crap they have today.

 

[psrountree]

"Torque" is why you get binding in tight,slow turns in a KJ with the 242 t-case.

When torque is applied to the differential it naturally wants both axles(or front/rear drive shafts in the t-case) at the same speed,the spider gears have alot of force being applied to them that takes a second or two to overcome and even then has alot of resistance to letting the axles(or driveshafts) spin at different speeds.

Without torque being applied this will not happen and why you don't feel it while in 2wd since no power("torque") is being sent to the front diff and the center diff is not being used.The rear diff is being "dragged" and the wheel are not "steering" so that slight binding is not felt.

Plus the 242 t-case is setup to bias the front/rear torque split(48/52 if I remeber correctly) since the KJ uses mis-matched diffs(D30A front and 8.25 rear) which do not have the exact same gear ratio,the front diff will spin slightly faster then the rear by design.You don't want the rear end to spin faster which would make it uncontrollable trying to drive in a straight line in 4wd.

The 242 t-case is almost a 40 year old system so it's pretty crude compared to the weak crap they have today.

I needed to select 4 part-time to park my boat on a wet lawn. Selected 2wd afterwards as normal but when I did a sharp turn at slow speed I got the same problem as has been dicussed here. Is this a common problem, lack of use, or just me ? Had a transmission specialist put it up on a hoist and it freed immediately. What if it happens again, can I just jack up a front wheel to free it ? Is there a preferred method ?

Peter

Sent from my SM-T310 using Tapatalk

 

[Billwill]

My Export 2.5 CRD Sport has only part time 4WD but it does have the Trac Loc diff at the rear.

I started picking up drag at the rear in turns even in 2WD so I bought some Mopar Friction Modifier from the dealers, drained and cleaned the rear diff, poured in the Mopar product and filled up with dino oil. Then did some figure of 8 turns as stated by the Service Manual.

This was years ago and it has been fine since then but I know what to watch out for in the future!

Just mentioning this in case other owners with Trac Loc are picking up problems.