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Stock Grand Cherokee Tech. All ZJ/WJ/WK Non-modified/stock questions go here!ZJ (93-98), WJ (99-04), WK (05+)
All ZJ/WJ/WK specific tech questions asked here!
Ok ive been on youtube all week. Learning and being a sponge. I spent more on tools so far than parts lol. But im planning to keep this jeep a while so....got her on jack stands and started to tear it apart. I did have some help . Take a look at how beat up that diff is. Im hoping i find one this weekend to replace it. Can i just take the gear assembly from another jeep and pop it in mine. Of course the right one lol. I have a dana 30 it says 40869-1 on the cover. So my question is how can i recognize that the diff I find will work? And what other years can I take from? What else will i need while i have it all apart? Im a noob to these type repairs. But im confident i can do it. I did buy ujoints, axle seal, pinion oil slinger and oil seal pinion. Im sure i need more but im pieceing it all from videos and forum threads to learn. I did buy a haynes manual which is en route. Im just gathering the parts and it should take a few weeks since im broke beyond belief lol. Thanks all for helping me out. Stay tuned for my progress.
I agree with this absolutely. Why would you spend any time trying to fix that POS. About the only thing it's good for is remelt. Any ZJ D30 will work as long as the ratio matches your rear one. The hardest part about the swap is getting the bolts out of the control arm bushings. You can count the teeth on that ring gear to figure out what ratio it is. I know the pinion is gone, but at least that will get you some idea. I may be wrong, but I think the 3.55 and the 3.73 use the same pinion. (I was wrong, I think)
Okay, after a little research, there appears to be 2 different cases. A low ratio case for 3.55 and down, and a high ratio case for 3.73 and up. I think the easiest way to find out what ratio you have is (if there aren't any tags) count the teeth in the REAR axle to get the ratio, then find a matching front axle from somewhere. (ring gear teeth divided by pinion teeth equals ratio)
Okay, second edit; tooth count 3.55, 39/11---3.73, 41/11.
Swapping in a new diff in it is not something easy to do,It takes some special tools and know how to get it right.For what the gears and diff will cost you you can pick up a used whole axle for and a lot less work to get in.
Thanks guys for the helpful answers. I did mention that at first to my boyfriend but he said we need to remove the springs to replace the axle and need a special tool for that. In any case what about changing the axle seals? is that not necessary then? I was going to do it since i was going to have it all apart. I might be missing something but i didn't think i needed special tools just to remove and replace a differential assembly case.Maybe im not saying it right. Im talking about the whole innards of the diff. i thought it just pops out after removing the cv axle and the bracket bolts? I wouldnt wanna hassle with a rebuild. I have seen all the tools needed for that and its clear this one is complete ****
Last edited by salvagedstitch; 03-25-2016 at 11:15 AM.
The differential assembly case is not a separate unit. It is part of the complete axle housing. The easiest way to explain it to you is to send you to [ur]jeep4x4center.com[/url] which is Morris jeep parts. Click on your jeep, then click on "Dana 30 differential parts" and "Suspension parts". These listings will show you exploded views of how the front axle is assembled and installed in the jeep. There aren't any special tools needed to remove the axle. The only things you need to do are remove the track bar, shocks, swap bar links, steering link, and brake hoses. Then jack it up until the springs fall out. Then disconnect the 4 control arms.
Its 40% off at the pick your part this weekend and a whole axle assby is 200 before 40% off so im gonna go that route. And thanks for that info dave1123 on how to remove the axle, that will make my bf happy to know we dont need a tool for the springs. but how about putting it back?
All you have to do is after connecting the control arms, set the springs on the lower seats and slowly lower the vehicle while guiding the springs into the upper seat pockets.
You know whats funny? Guys that go for extreme flex for rock crawling sometimes have the springs pop out! There isn't much holding them in.
Ok the axle is out. it wasnt fun. but it wasnt that hard. i pray to god we know how to put it all back!! Should I replace the bushings? Those black rubber pieces. Im not sure what they are all called. I am looking on morris trying to tell by the diagram what goes where. I will get some pics up later.
Last edited by salvagedstitch; 03-26-2016 at 02:12 AM.
Heres a pic of my back diff. Thankfully the markings were oit cuz the jeeps on jacks and i cant turn back wheels. Im guessing those last 2 numb are the tooth count so that makes mone a 3.55 ratio?
03-24-2016, 11:11 PM
Id say this differential is toast
. Take a look at how beat up that diff is. Im hoping i find one this weekend to replace it. Can i just take the gear assembly from another jeep and pop it in mine. Of course the right one lol. I have a dana 30 it says 40869-1 on the cover. So my question is how can i recognize that the diff I find will work? And what other years can I take from? What else will i need while i have it all apart? Im a noob to these type repairs. But im confident i can do it. I did buy ujoints, axle seal, pinion oil slinger and oil seal pinion. Im sure i need more but im pieceing it all from videos and forum threads to learn. I did buy a haynes manual which is en route. Im just gathering the parts and it should take a few weeks since im broke beyond belief lol. Thanks all for helping me out. Stay tuned for my progress. 
