JoshBrames

hey guys,
i'm having some trouble locating a diagram for the front differential on my 2000 cherokee sport. i let my roommate borrow my jeep a couple of days ago and he drove it in 4-wheel on dry pavement for 20 miles at an average speed of 50 mph. if you have not already guessed, the differential caught on fire. i haven't opened it up yet to see the extent of the damage but i want to have the diagram on hand to help me diagnose the severity. any help will be greatly appreciated.


you can reply to this thread or directly to my email: josh_brames@live.com.

thanks!

BuckB91XJ

How in the heck did driving in 4WD cause a 2000 front axle to catch fire?

Your 2000 XJ has the non-disco type of front axle. Whether you are in 2WD or 4WD, the front axle, differential and driveshaft are always turning.

XJSETH

you could just go buy a chilton repair manual. might have it in there. How did the diff catch on fire?!?!?! i drive my lifted jeep with heavy tires in 4-hi 20 miles to and from work when its icy outside. never had any heat issues. my guess is something was wrong already and him driving it made it worse and caused alot of heat, im not too sure tho.

mike37

http://www.discountjeepparts.com/ima...s/omix/d30.pdf

98 JeepJeep

JoshBrames

I don't know exactly what went wrong as I wasn't in the jeep. I do know that running continuously in 4-wheel on a surface that has no traction issues at high speeds is bound to cause a lot of friction. The heat that would result would compromise the integrity of the differential lube letting the friction build even more heat. This is all speculation. I've never had to work on a differential before and I know almost nothing about them. What I do know is that there appears to be a hydraulic hose that fits into the top of the differential on the back side. (I assume that this hose runs from the actuator.) This hose is burned to hell and the heaviest concentration of soot is around the hole that this hose fits into. I figure the differential got hot enough to either melt this hose or blow the fitting and exposed the oil inside to the air outside resulting in combustion. I'll post some pictures and you can tell me what you think.

finneys98xj

junk yard is your friend is all i got to say

Desertfox1023

x2 a 2000 model I'm pretty sure is LP axle. Take this as a good time to go out and grab you a much better HP D30 out of the junk yard with 297x ujoints. XJ's with ABS or 97+ have 297x ujoints. Also you can probably just go and get any HP D30 from an XJ and put your shafts in it. My guess is that the front differental was leaking and got low on fluid. Did it lock up on him or just get really hot?

JoshBrames

It never locked up all the way, he said it started jerking so it was trying to lock up.

GreenClassic

Why was he using 4wd on a dry paved road anyway?

JoshBrames

He had used it to get out of a driveway and didn't know that he didn't get it out of 4 wheel when he got to the road. It is obvious when that jeep is running in 4 wheel so the only answer is that he is oblivious to his surroundings.

caged

to me, it sounds like the fluid was low, and the "hydrolic" tube, which is actually the breather tube has melted, closing it up not letting it breath.

i've never heard of this happening. and i've driven my 99 tj on the 401 on dry pavement in 4hi a few times, not knowing the 4wd was engaged. my lights on dash don't work.
matter of fact, i just did it yesterday. drove at 120kph for 60 kms. and my front pinion seal leaks. nothing happened. however, it was -29c out yesterday.

he wasn't in 4lo, i hope. lol.

good luck with that, as mentioned, time to get yourself a hp d30 from a wrecker out of a 99 xj. that way it has the larger u-joints and correct brake caliper mounts.
do it all yourself and learn/save lots.
keep your bad diff for spare shafts etc. if they're any good still.

cheers.

OverlandZJ

Pull the diff cover off and show us a pic.

That hydraulic hose you mention is actually the breather hose. It runs to the firewall on drivers side. I'm betting this somehot got close to your exhaust manifold and burned it.

The bind you described is actually normal in 4wd and on a non slip surface. I'm betting the axle is fine, but you'll need a new breather hose.

Post pic of the diff and we'll better know what your looking at.

mike37

the front axle turns all the time regardless of weather its in 4x4 or not
him driving it in 4x4 on the rode is completely coincidental
to the problem
you didn't have fluid in the axle cus of a leek or water intrusion
it just got hot from no lubrication
like other have said the hose is a breather