84 XJ diffs into 90 YJ?

G

gulkster

New member
Hi there,
I am very new at Jeeps, and marginally skilled at "back-yard" mechanics (the internet is a friend). I can't seem to find anywhere if the diffs from an '84 cherokee (XJ) would fit into my '90 YJ. They both have Dana 30/35 setup, but are there any differences that would make them unusable in the YJ? Sorry if this is a stupid question, but I see Dana 30s have many different incarnations, and I don't know the ins and outs as it were, of how interchangeable they are. Thank you in advance for any help. I will need install kits I'm sure, just want to make sure everything will "mesh" (sorry, that was uncalled for).

p.s. I am interested in this as I want to change my stock 3.07s with the 4.10s or 4.56s that should be in this XJ vehicle. I just don't want to waste the sellers time, nor my own. Thanks again.
Jamie
 

The internals should fit. The housings are different. The xj is coil front susp and and the rear is spring over axle not like the spring under of the yjs.
 
Here's some info I found on XJ ratios:

3.07 - used with 4.0L engine / manual transmission
3.31 - only available on older (pre87?) 2 door XJs with "Fuel Economy" package
3.55 - used with 4.0L engine / automatic transmission
3.73 - found in some XJs with the towing package
4.10 - used with 2.5L engine usually, and older XJs with the "Off-Highway Vehicle" package.
Source: jeephorizons.com

No mention of anything lower than 4.10...

I, too, had 3.07s in my YJ (89 6cyl/auto) so I swapped axles with a 94 YJ (4cyl/manual) that had 4.10s
 
jeep hasn't put deep gears into factory axles since the motors made more than 75 hp.

Your swap is simply not worth it, in the end your gonna have to fab up new perches for the front and swap the rear to the bottom of the axle shaft. Look for a 87-89 XJ for the rear D44 or an 95-00 exporer 8.8. both stronger axles.

If you simply steet drive and are looking for better gears, look for a 4cyl yj with a 5 speed, that all have 4.10 gears and will be a direct swap into your jeep.
 

Thanks everyone for the helpful replies. The 4cyl auto XJs are either 4.10 or 4.56s according to wikipedia. I am swapping diffs, not housing/casing/axle tubes etc. If they fit, as Jesse mentioned, then this is a nice upgrade to my stock diffs. Now I need to buy them, and figure out how to set backlash :)
 
2.5L autos are commonly 3.73 gears, regardless of what wikipedia says. 4.10 gears are most commonly found under the 2.5L 5spd. 4.56 are very rare but can be found in some very early 2.5L XJ's.
 
One thing make sure you check to see that both front diffs are either high or low pinion. I believe they are cut diff so the gears won't work unless they are the same.
 

This XJ is an 84...doesn't get much earlier than that ;) I will count teeth of course before I take it home. 4.10s would be fine too of course. Jesse, how can I check/measure if they are high or low? A picture of one style would be great if you happen to have one, or any description of the main differences would help too of course. Thanks.
 
The front high pinion diff the pinion gear goes in on the top of the housing. For added ground clearance. Most Cherokees till the late 90s were high pinion. I will grab a picture I will try for one of each. I'm a tech for Chrysler up here in Alberta so we should have something on the lot lol.
 
Thanks Jesse. I've attached a picture I have of my front diff (not a great one I know, but hopefully it will help). Is this high or low? When you say "on top" do mean top-halfish? My front pinion seems to be nearer the top of the casing (when compared to the rear)...I think :redface:
 

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The first one is a low pinion note the pinion is on the lower portion of the casing. And vice versa. For the other
 

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Thanks bounty. I wasn't sure all I've owned is xjs and a few big block chiefs.
 
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