Engaging 4x4 keeps pulling driveshaft out rear diff and breaking stuff

jaaylynch

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Jan 26, 2022
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Hey guys, so i have a 2000 tj sport and the last 2 times i tried putting it in 4x4 it pulled the rear driveshaft out and shattered my transfer case, most recent time it popped out and is still in but there is play in the pinion seal and driveshaft is just spinning inside the differential and when i try to drive it sounds like gears grinding and wont even move unless in 4L. i had a mechanic check the gears prior to using it and he said it was 3.73 ratio front and back 41-11 which gave me the impression it was okay to use and i tried getting into my driveway and it just popped out less than a foot away and now im frustrated trying to fix this and figure out what it could be that the previous owner did that caused this multiple times. any help is appreciated and no it is not lifted im running wrangler duratrac tires as is right now. any suggestions?
 
this is his response on the invoice, i believe the 41-11 was a reference to the ratio being 3.73
invioce jeep.jpg
 
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Ah, re-reading your post it sounds like you blew your rear diff and maybe the transfer case. At a minimum the rear is obviously toast.

Edit: doesn't seem like you did anything wrong, it happens
 
any insight on what may have caused this? ive never put it in 4wd and been succesful and the 2 times i tried this happened so im confused as to what keeps going bad in the rear and is there any way to test without blowing it up again if i get it all fixed?
 
Driveshaft length maybe. Extreme pinion angle maybe. Different ratio axles front and rear sounds like the obvious culprit.

I'd pull the covers and read the numbers stamped on the ring front and rear.

We're going to need to know a lot more...is the jeep lifted? SYE? Pictures help.

-Mac
 
exactly!!! thats why im confused as to why it just blew out like that, do you know anything that would cause it?
Any chance your driveline angle/ alignment is changing when under load? Worn control arms or transmission/ motor mounts?
 
any insight on what may have caused this? ive never put it in 4wd and been succesful and the 2 times i tried this happened so im confused as to what keeps going bad in the rear and is there any way to test without blowing it up again if i get it all fixed?
Until proven otherwise, my money is on a missing skid plate, rusted exhaust holding up the drivetrain and the load from driving in 4 low makes it shift too far and pull the driveshaft out. What do I win?
 
exactly!!! thats why im confused as to why it just blew out like that, do you know anything that would cause it?
Can you post some pictures of the underbody of the jeep? Especially around the skid plate, transfer case, driveshaft, rear differential, and rear suspension.

For those not very familiar with the TJ, it is often very difficult to spot issues. But sometimes people familiar with them can instantly spot the issue and call it out. Not always, but there is a good chance we can spot it.
 
Can you post some pictures of the underbody of the jeep? Especially around the skid plate, transfer case, driveshaft, rear differential, and rear suspension.

For those not very familiar with the TJ, it is often very difficult to spot issues. But sometimes people familiar with them can instantly spot the issue and call it out. Not always, but there is a good chance we can spot it.
Wouldn't be the first one driving around without a belly skid and a mechanic missing that.
 
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Can you post some pictures of the underbody of the jeep? Especially around the skid plate, transfer case, driveshaft, rear differential, and rear suspension.

For those not very familiar with the TJ, it is often very difficult to spot issues. But sometimes people familiar with them can instantly spot the issue and call it out. Not always, but there is a good chance we can spot it.
Wouldn't be the first one driving around without a belly skid and a mechanic missing that.
My guess is that the rest of would have a 50-50 shot of identifying that one in a picture....

:)
 
my money is on a missing skid plate
First thing I thought of too

Just re-read... is it the front or rear axle that is just spinning?

Also, walk us through step by step what you did to put into 4wd...

And pics help a lot..
 
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