Big Question URGENT
03-06-2019, 06:29 PM
#17
Senior Member
as far as i know np242 and 99% of time when i need 4x4 i use part time 4wd, never used 4low ever and very rarely 4hi. I assume it must be friction in the diff hub caused by the tyres, but then i didnt use 4wd when this happened. Then again this only happened after i put those smaller tyres on front. Tyre place said it will be ok but now i dont know. I hear no sounds at rear and today i drove 20km and nothing happened. I would like the cause so i can prevent this and fix the issue. The diff is dana35 and 30 in front
03-06-2019, 08:14 PM
#18
CF Veteran
Join Date: Aug 2011
Location: Nor-Cal Coast
Posts: 10,489
Likes: 0
Received 17 Likes
on
17 Posts
Year: 90,84
Model: Cherokee
Engine: 4.0,2.5
Somebody correct me if I'm wrong here. I thought the 242 in full time wouldn't bind the front and rear as they are not locked. Just for a short bit with mis-matched tires might be OK? Strandwolf, now and then I get "clocked" by something unexpected out of left field. A couple of weeks ago I'd lifted my E-brake lever a bit to reach something in the council there. later after a short drive with no issues my rears locked up! Huh? Then I found the problem. Seems the shoes grab and lock going forward with tension on the E-brake cable, (DUH), but with just a little tension it might be free, or lock.
Adjusting the brakes it's important to first manually adjust the star wheel on the rears. (It's suppose to be "automatic", but often isn't). Once that's done likely the E-brake will be fine. (that cable doesn't stretch easily). My point here, if someone didn't get that and tightened the E-brake cable with the star wheel adjustment loose, possibly the auto adjust tightened the wheel with the cable over tightened. A bit of a stretch, but that could cause the rears to "randomly" seize.
Adjusting the brakes it's important to first manually adjust the star wheel on the rears. (It's suppose to be "automatic", but often isn't). Once that's done likely the E-brake will be fine. (that cable doesn't stretch easily). My point here, if someone didn't get that and tightened the E-brake cable with the star wheel adjustment loose, possibly the auto adjust tightened the wheel with the cable over tightened. A bit of a stretch, but that could cause the rears to "randomly" seize.
03-06-2019, 08:29 PM
#19
Senior Member
You’re wrong but not by your own fault just a misunderstanding . The 242 in FT doesn’t bind like a 231 in PT with correct size tires when turning ... however any transfer case with mismatched tires will bind as it is essentially the same as having mismatched gears front and rear .. the front or rear is trying travel faster or slower than the other end... make sense now?
03-06-2019, 08:52 PM
#20
CF Veteran
Join Date: Aug 2011
Location: Nor-Cal Coast
Posts: 10,489
Likes: 0
Received 17 Likes
on
17 Posts
Year: 90,84
Model: Cherokee
Engine: 4.0,2.5
I'm listening but not convinced. I happen to have one of each. I am indeed sure my 231 locks front and rear effectively making it "two wheel drive", (won't stop unless one front, and one rear looses traction). I have not tested the 242 in full time. It's my expectation that it can spin just one, front or rear, and be stuck. (that would be why there is a part time option, locking the front and rear). Otherwise in "full time" it will indeed drive all four wheels as long as they all have traction.
03-06-2019, 09:30 PM
#21
Senior Member
I'm listening but not convinced. I happen to have one of each. I am indeed sure my 231 locks front and rear effectively making it "two wheel drive", (won't stop unless one front, and one rear looses traction). I have not tested the 242 in full time. It's my expectation that it can spin just one, front or rear, and be stuck. (that would be why there is a part time option, locking the front and rear). Otherwise in "full time" it will indeed drive all four wheels as long as they all have traction.
Last edited by GreaseMonkey17; 03-06-2019 at 11:59 PM.
03-06-2019, 09:43 PM
#22
CF Veteran
Join Date: Aug 2011
Location: Nor-Cal Coast
Posts: 10,489
Likes: 0
Received 17 Likes
on
17 Posts
Year: 90,84
Model: Cherokee
Engine: 4.0,2.5
A note to the forum or anyone following this. Likely it would be wise to ignore both of us, the correct info is out there somewhere, but not here. (I'm more than 52% sure of that!)
03-06-2019, 10:26 PM
#23
CF Veteran
The 242 has an open differential when it is in full time 4x4 so yes you could run different size tires in full time but I wouldn't recommend it. Since the front and rear are not locked together in full time, yes it is possible to get into a situation where only the front or only the rear is spinning, I have done that before.
Last edited by 00t444e; 03-06-2019 at 10:38 PM.
03-06-2019, 10:49 PM
#24
Senior Member
The 242 has an open differential when it is in full time 4x4 so yes you could run different size tires in full time but I wouldn't recommend it. Since the front and rear are not locked together in full time, yes it is possible to get into a situation where only the front or only the rear is spinning, I have done that before.
Last edited by GreaseMonkey17; 03-07-2019 at 12:02 AM.
03-06-2019, 10:50 PM
#25
Senior Member
03-06-2019, 10:52 PM
#26
Senior Member
http://www.fourwheeler.com/how-to/tr...ransfer-cases/ here guys... I went back and tried to edit my post to be much more understandable and got rid of my original typo on the torque rates lol I post from my phone and it’s easy to think faster than I type and not post the information as well as I want to . I hope this helps clear things up . In full time the front and rear diffs act as an open differential within the transfer case sending 52 percent to the rear and 48 percent to the front when needed due to torque bias . When using part time you’ve got equal torque being applied through the front and rear drive shafts so when you’re turning hard and driving slow the wheels bind because of the differentiation that the turning of the wheels create vs the rear axle driving straight with the same speed of the driveshaft applied ... so in part time with mismatched tires you’d immediately be bound and after a short trip on solid ground the weak link would be shown real quick like ... if I’ve made any mistakes be sure to scream and curse at me lol as I’ve tried to correct everything as much as possible
Last edited by GreaseMonkey17; 03-07-2019 at 12:11 AM.
03-07-2019, 01:54 AM
#27
CF Veteran
Join Date: Mar 2016
Posts: 3,211
Received 605 Likes
on
515 Posts
Year: 96
Model: Cherokee (XJ)
Engine: 4.0
one item that may not have been mentioned is the rear rubber brake hose...may be collapsing internally
I have had this one 30yr old cars, brakes lock on...one way to tell is your afflicted hubs will be very hot
cheap to replace, I have a 4" extended one awaiting my fitment
re the tyre size difference... I could be wrong, have been before, but being in FT 4wd, with different tyres on each axle may make the Transfer case internal diff work at full load, 100% duty cycle,
instead of its range of normal operations, where both load & duty cycle would be much less
I have had this one 30yr old cars, brakes lock on...one way to tell is your afflicted hubs will be very hot
cheap to replace, I have a 4" extended one awaiting my fitment
re the tyre size difference... I could be wrong, have been before, but being in FT 4wd, with different tyres on each axle may make the Transfer case internal diff work at full load, 100% duty cycle,
instead of its range of normal operations, where both load & duty cycle would be much less
03-07-2019, 04:29 PM
#28
CF Veteran
Join Date: Aug 2011
Location: Nor-Cal Coast
Posts: 10,489
Likes: 0
Received 17 Likes
on
17 Posts
Year: 90,84
Model: Cherokee
Engine: 4.0,2.5
Yea Awg, a collapsed line gave me some grief in an MG Midget clutch once. That sucker worked like a one way valve and held the clutch disengaged, but looked fine on the outside.
Thread
Thread Starter
Forum
Replies
Last Post
N20jeep
Other Vehicles. Other Jeep models & cars and trucks of other makes
17
04-15-2011 06:20 AM
Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)