jeep knowledge requested

Ok, im totaly dumb to jeeps and dana rear ends, too lazy to join a 4x4 club so here goes...

I've got a 96 JGC (ZJ) 4.0l auto 4x4, the rear end is crazy knocking and noises, hard for me to explain, maybe i can get a vid if needed but i digress. Me and a pal jacked up the rear, put it in drive and pinpointed the noise to be in the differential. What's worse is that we decovered about 1/4 to 1/2in of in/out play on the passenger side rear wheel. No side to side or up and down...

I duno whats wrong but im not intelegent enough yet to figure it out and this is the daily... Also not much cash so rebuilt by a shop is out. So my questions are this

I've already figured out that i have a dana 35, not sure its a 35c or not, but there are no tags on the entire Axel, so how do i verify ratio and soforth without taking anything apart? Unfortunatly this is still our daily but luckily we only travel about 20 miles a day total.

2ndly, what rear ends can i use to drop in and go? Will any jeep d35 work? And how varying are the gear ratios? Id like to keep the same ratio for 4x4, but I'm starting to not give ducks...

Also, i have rear disks, if i can use a rear that has drums, can i swap for the disks easily? Whats involved?

Any info would be apreciated

The 35c was only used in regular cherokees and comanches(XJ and MJ). The ratio should be 3.55 if its the 4.0 but if it has the towing package its a 3.73. Any 35 other than the 35c should fit and you can get them for next to nothing usually. You also have dana 44's, ford 8.8's, etc.. The brakes might be an issue because of ABS but you should be able to find a 35 with disks fairly easily.

Also here is you a D44 out of a 98 ZJ with limited slip for $300 craigslist that will be 3.73 ratio but its not like 3.73's for the D30 front is that hard to find.

Being a 4.0L you most likely have a Dana 35.. The in and out play will be due to the C-clips that hold the axles in place.. Having some play is normal... If you think its your problem its very easy to inspect.. I don't suspect it to be your problem though...

To inspect it you take the tires off.. Drum brakes you just take the drum off, disc brakes you just take the pads/rotors/calipers off... Take your rear cover off.. Take the roll pin bolt out, then push each axle in wards 1 at a time.. Take a magnet and take the c-clip out.. Then you can pull the axle out and inspect for ware...

Whats your noise like? When are you getting it? How can you get it to act up?

Does it have a rear sway bar installed? do the end links have ball socket type joints??

Afa abs i don't think i have it but I'm not sure... Maybe... So any d35 from any 4.0l jgc will work? Is it just jgc only?

Kind of like a rythmic bearing noise if i had to guess... Comes on at any accell and decel, if i keep throttle even seems to almost go away... Driveshaft/ujoints didnt seem bad and the sound was concentrated in the center of the axel Just looking for the quickest cheapest solution to fix it for safe driving

Pics and video tomarrow, i really gotta fix this asap thanks for info so far

In reply to VG30_S12: for the ease of swapping then yes it needs to be from another 4.0 jgc zj if it isnt then you have to move all the mounting points for leafs/coils/trackbar etc... Unbolt old then bolt on new.

So wait, your telling me the mounting points are different, but they change by bolting on new mounting points onto the "new axel" or do you have to weld the new mounts? Also how difficult is it to change pinion gears? I thought you had to be a master mechanic to do it? I'm just a guy with wrenches

In reply to VG30_S12:

Before shopping for another axle try removing the diff cover and inspect first, the least you'll be out is a gasket or RTV and some gear oil. 1/2" axle endplay is... kinda excessive tho.

if you don't have a tag, you can figure out the ratio - rotate a rear wheel one revolution - count the revolutions for the driveshaft/pinion. Go find junkyard rear end with the same or jeep guy who upgraded to a d44. Don't get an unmatched ratio if you are not planning on changing the front - bad juju.

You need a new ring and pinion, but I'd bet all the bearings are gone by now as well. It's a simple junk yard swap, or get a kit from Randy's Ring and Pinion or something. The Jeep has a 35C, the C is for c-clips. The D44 from the 5.9L Limited or TSI model is an aluminum housing unit. The housing flexes too much, I'd avoid it.

Ok, update and more questions... I picked up a good deal on a 96 jgc rear, looks identical to mine but rustier but can't complain for 160 bucks delivered with dshaft and calipers and rotors

Anyway, how can i check it? Im gunna pull the cover and look butt what am i looking/listing for? Axels had a lil in/out play. It turns with no noise... Also hows that turn wheels ito figure gear ratio thing go?

The in and out play, endplay, is normal....unless you see something when you get inside.
When you get inside look at the ring (the big ring) and pinion (the one going through the nose of the diff) gears for nasty wear. This diagram shows what to look for

I'd also be sure to look at the bearings and the races. Look for anything that's not almost mirror-like. You have bearings on the diff carrier, and another set of roller bearings in each axle tube.
Since you're taking everything apart, instead of counting the pinion revs and comparing that to wheel rotation, I'd just count the teeth in the ring and pinion gears and divide them. I bet it's around 3.27:1.

Unless you are making a point of learning about differential service and repair, i would swap the rear end out for a good used unit at this point. Your noise and wheel play guarantee that you have more than one issue going on here. Fixing it would be tedious and expensive vs getting a junkyard unit.

Yes, but it'd be a HUGE learning experience. And the junkyard axle might have the same issue. If you never learn how to fix anything, you end up with too many puppies. Wait, wrong definition of "fix". Anyway, the JY axle has the same endplay as the one he's pulling out (as will every c-clip axle he'll buy). The JY axle might have noise, he'll never know until you get it in service. But it you know how to read wear patterns, you will know before it goes in. Once you see what's going on in an engine, trans, cylinder head etc. you are much more prepared to tackle your car problems. Plus, it's fun!!

That's the thing i don't know how to read wear patterns an rebuild engines and headgaskets and such. That's why i didn't want to rebuild it myself (also stated before, this the only vehicle roadable atm) if this were a race car or a project car, I'd probably attempt it (still lacking specialty tools)

Local shop(east coast gear supply) quoted me for a full rebuild at about 1k, noting the d35 is junk and sugguested an ford 8.8 upgrade at the $1200 price point... As nice as that might be we don't have it and I'm not experienced enough or confident enough to tackle it

I just hope this jy rear is good :(

complete ford 8.8 bolt in for a ZJ $725 about $850 after all the adapter and brake options you will need main thing is the adapter yoke for the u joint.

If you aren't going to wheel it with 33" tires, I'd just drop in the JY axle, just make sure you get a 30 day guarantee. That chart I listed is all you really need to read the wear patterns, but I totally understand.
Don't bother with the 8.8 swap unless you need the extra strength. The only weak aspect of the 35C is that if a c-lip breaks, the axle will walk out of the axle tube. I've only seen that happen though when it's being abused, i.e. 33" tires, more HP, serious 'wheeling and the like. And that's with years at a Jeep dealership.

No no serious abuse, just daily family hauling and an occasional car tow... Sad part is its about to bee too small for my family in a few months :(

Wear didnt seem bad if i read it right, got a new gasket on and filled with one bottle lucas and two qts 80w-90 Turns nice and smooth so hopefully its good starting to put it in twomarrow... Btw i wana thank whoever posted that stuff about cars falling off jackstands, i was already nervious about it before lol