i hate jeeps

[MUDKICKR]

sorry guys i just have to rant to somebody, has anyone in here ever broke a transfer case in half? like the part for the frt driveshaft is completely broke off the rest, its my 2000 jeep wrangler and now looking for a transfer case np231 pos i wasnt even doing anything stupid at the time, just left the trail for 4-wheeling and going down the road about 60 and BOOM. a solid axle frt end and no lockin lockout hubs junk

 

[Cheaper Jeeper]

Yes I have. Broke the transfer case casing in my Dakota 4x4 in two. It is the NP 231D (D=Dodge). The front U-joint on the rear driveshaft spit a cap at 70 mph and the driveshaft dropped a couple of inches off center. The resulting excentric motion of the driveshaft cracked the casing in half before I could get it stopped. So it really is more of a New Process model 231 transfer case problem than a Jeep problem....

Were you in 4 HI doing 60 in the dirt? If so, that may have something to do with it. If you hit a non-slippery surface while in 4WD anything that makes your front & rear wheels turn at different speeds (like making a turn) when they have traction will bind up the drivelines and something has to give....

 

[towcat]

Were you in 4 HI doing 60 in the dirt? If so, that may have something to do with it. If you hit a non-slippery surface while in 4WD anything that makes your front & rear wheels turn at different speeds (like making a turn) when they have traction will bind up the drivelines and something has to give....

he left the dirt and was going down the road doing 60(if I am reading this right) If he was in 4hi, the case would have blown if he went around a slight curve. Like you said, something's gotta blow.

 

[Cheaper Jeeper]

he left the dirt and was going down the road doing 60(if I am reading this right) If he was in 4hi, the case would have blown if he went around a slight curve. Like you said, something's gotta blow.

You know, I may have read that wrong because of the way it was typed.

I read it as "left (on) the trail FOR 4-wheeling" (as in just started on the trail). I think you may be right and he meant "left the trail FROM 4-wheeling" meaning driving OOF the trail ONTO the pavement. If that's the case then that's definitely the problem.

The NP231 is a "part time 4WD" transfer case - which means it can only be used in 4WD on low traction surfaces - gravel, dirt, mud, snow, etc. It CANNOT be used on pavement in 4WD because the front & rear drivelines are "locked" together inside the transfer case and cannot turn at different speeds. If they they are FORCED to turn at different speeds - as in when turning a corner - either one of the drivelines, axles, or the transfer case is gonna' blow - just like what happened to you MudKickr.

In order to drive in 4WD on dry pavement, you need an NP242 - which has a FULL TIME 4WD postion for the shift lever. In full time 4WD the front and rear driveshafts are NOT locked together and can turn at different speeds - allowing you to drive on dry pavement in 4WD without damaging anything.

If you replace your NP231 with another one just like it, remember NO driving in 4WD on dry pavement. Or you can just as easily (for a little more money and maybe a little more time looking for one) get and install an NP242...

 

[partyncwby]

I'll give ya 500 bucks for your jeep and take it away so you don't have to look at it anymore.

 

[MUDKICKR]

500 bucks, wow that sounds tempting, but i cant do that. the tru-tracs in the frt and rear, the 4.88 gears and the 4" lift and the 33" tires cost a little more then that so ill keep it for now but thanks for the offer. ok i think you guys arent thinking about the diffs when you are thinking about driving it on dry pavement, the diffs give not the transfer case but after tearing it apart i found the problem. the frt driveshaft slip-yoke was locked up and wasnt sliding and put pressure on the t-case, stressed it to much and BOOM, broke it.(i love parts that move and dont have grease fittings) the way ive set this jeep up i really dont put it in 4wd unless it is really muddy, it goes great in 2wd, but i was in 2wd, driving down the main road rt 35 in wv, but oh well live and learn

 

[Cheaper Jeeper]

500 bucks, wow that sounds tempting, but i cant do that. the tru-tracs in the frt and rear, the 4.88 gears and the 4" lift and the 33" tires cost a little more then that so ill keep it for now but thanks for the offer. ok i think you guys arent thinking about the diffs when you are thinking about driving it on dry pavement, the diffs give not the transfer case

SOMETIMES, but not always. When you have 4.88 gears the teeth are so much smaller, that yeah, they'll give up first. Sometimes the u-joints give. Sometimes its the yokes, and sometime its the t-case. i've seen all of the above at different times. Just depends on what has been beefed up and what hasn't - whatever's beefed up the least is usually what becomes your "fuse"

...but after tearing it apart i found the problem. the frt driveshaft slip-yoke was locked up and wasnt sliding and put pressure on the t-case, stressed it to much and BOOM, broke it.(i love parts that move and dont have grease fittings) the way ive set this jeep up i really dont put it in 4wd unless it is really muddy, it goes great in 2wd, but i was in 2wd, driving down the main road rt 35 in wv, but oh well live and learn

That's a weird one all right. you know you can replace the grease seal/cap on that slip joint with one that has a grease zirk, right?

 

[MUDKICKR]

ok stupid question, why would a manufactor build a 4wd and design it to not be used in 4wd on dry pavement? i dont understand where your coming from on that, i didnt mean the axles would break first(i said give) i meant they will allow the transfer case to be locked while they give (slip,go faster or slower) around a curve. if the transfer case does lock when you put it in 4wd then the frt and rear driveshafts will turn at the same speed at the same time. i understand that. but that would make the frt and rear diffs do the work of spinning faster or slower when going around a curve( the job of spider gears to move and let the outside tire go faster and the inside tire to go slower)i do have the tru-tracs frt and rear, but like any locker they will give(unlock) when going around a curve, but i do know when you add bigger tires and a lift and lockers you will find your weakest links. but i dont see putting it in 4wd on dry pavement and breaking the transfer case apart. after i took everything apart i looked at the case, it had a lot of stress cracks in it and the part for the frt driveshaft was broke off completely(the chain was the only thing holding it all together) i looked at the slip yoke on the driveshaft (factory without grease fitting) and had to take a hammer to move it so that is the only thing i can see that would break the transfer case as it was, and when it goes back together i will drill and install a grease fitting, but i grease every grease fitting about everytime i get back from 4-wheeling and i have tried to spray stuff in that yoke but it didnt work, usually i go play on the weekend, take it to work on monday, after work put it on my lift at the shop and start greaseing it and cleaning the brakes

 

[ELIHMAN]

Buy an IH scout because Jeep is a 4 letter word!!!

 

[Shadetreemechanic]

The differentials solve the problem of individual wheels traveling farther in turns, thats why all vehicles have them. The reason your transfer case will **** the bed when in 4wd on dry pavement is that the axles will also travel a different distance in turns and will bind up the transfer case. In order to drive on dry pavement in 4wd you need a transfer case with a center differential, that will distribute power unequally between the axles as needed.
you can imagine where the strain will be if the front driveshaft spins faster than the rear one....Transfer case.

 

[69oiler]

it's true the front and rear driveshafts turn at different speeds when turning. your front wheels are turned and your rear wheels are pointed straight ahead. the only way to have the front and rear driveshafts turn the same speed when turning would be to have 4 wheel steering that steered the rear wheels exactly the same as the front wheels so both axles would be traveling the same distance relative to the ground.

 

[MUDKICKR]

so how does the manufactor warranty that? ive driven this jeep several times on dry pavement in 4wd and never a problem, while towing as well (have to move my diesel trk around somehow when its broke) when i take apart this transfer case to put the parts into another case housing i found ill see how its set up

 

[69oiler]

every part time 4x4 vehicle i have had had a sticker or said in the owners manual "do not operate in 4wd on pavement". they won't warranty it if they know it was driven on pavement in 4x4

 

[partyncwby]

Buy an IH scout because Jeep is a 4 letter word!!!

Tractors are for Farmers.....

JEEP

 

[subway]

it's true the front and rear driveshafts turn at different speeds when turning. your front wheels are turned and your rear wheels are pointed straight ahead. the only way to have the front and rear driveshafts turn the same speed when turning would be to have 4 wheel steering that steered the rear wheels exactly the same as the front wheels so both axles would be traveling the same distance relative to the ground.

yep.....with a 50/50 power splitting case like you have you SHOULD NOT drive on dry pavement locked into 4x4. it is very ******* the components straining them to try to equalize the torque build up when turning.

like said the differentials will do this side to side but you need a center differential to do this front to back on dry road. there is enough give off road or in bad driving conditions this isent a problem.

if you drove on road this way there is a very good chance the case was stresses before and just happened to give out then. not everything gives up at the time of stress, stressed parts can show up later, just ask some people who have had there cars rebuilt from an accident.

sorry about your luck, wish you the best getting it back together.