2005 Jeep Grand Cherokee Front Differential Mount FixPosted in How To: Transmission Drivetrain on May 28, 2014
We’re fairly certain that when Chrysler’s engineering team axed the WJ’s traditional solid front axle in favor of a completely independent arrangement in the ’05 Grand WK, what they didn’t anticipate was the front end becoming completely independent. See, we’ve recently added an ’05 Grand Cherokee Limited to the fleet -- and unbeknownst to us upon purchase -- its front differential had been working diligently towards parting ways with its host Jeep. Its means of escape? Three steel-sleeved rubber bushings serve as the sole connection points between differential and subframe, and the majority of them were screaming uncle after eight years of arm wrestling with the Hemi under the hood.
We’re not entirely sure why the resulting clunking and intermittent driveline vibrations went completely unnoticed during our initial test drive -- but if they had -- Jeep-buying protocol usually dictates that completely roached wear items be put to good use as leverage against seller’s asking price. Oh well. Used is used after all, and we’re guessing that the lifespan of these bushings was immediately expedited under our ownership thanks to gratuitous, teenager-like use of the go-pedal. We weren’t entirely to blame, however. A cursory Interweb search told us we weren’t alone, and that premature differential-mount failure (our Jeep has less than 90K on the clock) was pretty common in both WKs and the Commander XKs that share the same platform.
Since there seemed to be no shortage of questions online revolving around a solid plan of attack for those replacing these bushings at home, we’re gonna give you a play-by-play here. We’ll show you how we tackled the job and hopefully make it suck a little less for you. Since our local parts store didn’t show a listing, we sourced new OEM-bushings from our local Jeep dealership to the tune of about 200 bucks. Two out of the three bushings are pressed into large, cast-in eyelets -- one above the differential pinion (the most haggard of the bunch) and the other above the output for the right-hand CV shaft. Of course, the only one out of the bunch that was bolt in and easily replaced -- the front-support bushing -- was the only one that was A-OK. Who’s to say how long that one would last, though, so we replaced it for good measure. We tackled this job with the benefit of a vehicle lift and our friends at Importech in Conway, New Hampshire, to help document the story, but if you have a basic tool-set and a decent idea of how to employ it, you’ll have success at home with a floor jack and a pair of strategically placed jack stands.
The clunking sound that originally indicated that a problem needed fixin’ was most noticeable when shifting from Park to Reverse or Reverse to Drive. A glance underneath -- with a buddy depressing the brake and rowing the gears -- made for a quick diagnosis. Whenever the torque load changed directions, the differential ends of the CV shafts would jump vertically over an inch in either direction.
With both knuckles and strut assemblies still attached to the lower control arms, we pulled the top of the knuckles out and away from the vehicle enough so the CV shafts would pull free from the housing. Now you’re ready to unbolt the driveshaft from the differential, yank the vent tube, undo the electrical connection up top, and zip-out the bolts that run through the three mount bushings (arrows).
After popping the front wheels off and setting them aside, we gained access to the front driveline by removing the large skidplate bolted to the subframe. You need to fully remove the rear two bolts, but just loosen the front two enough to slide the skidplate forward in its slotted channels and let the washers pass through the holes.
You can see where the rubber of the pinion support bushing tore and began parting ways with the steel shell. With a long punch through the center sleeve for leverage, we could tweak the sleeve side-to-side to the point where it contacted the outer steel shell of the bushing. Not good. If we’re able to manipulate the bushing this much with a punch, you can imagine the hurtin’ that 375 lb-ft of engine torque put on it.
There’s no need to completely disassemble your front suspension, unbolt the axles from the unitbearings, or touch the brake hardware to tackle this job. By simply unbolting the upper control arms and outer tie-rod ends from the knuckles and the sway bar end links, we freed things up enough to pop the CV shafts out of the differential.
The quickest and most effective means of relieving your differential of its spent bushings is with an air hammer wearing a chisel bit. We used the air hammer to bend the lip of the steel shell inward towards the center of the bushing and then pushed the entire bushing out towards the non-lip side. One bushing is pressed into a more-damage-prone aluminum housing, so be sure to take your Machine Gun Kelly hat off when you blast that one out.
It took about five minutes per bushing to jackhammer them free of the differential -- definitely not pretty, but effective. The same goal can be accomplished with a hammer, chisel, and sizeable steel-punch, but you’ll probably wish that you had borrowed your buddy’s air hammer when through. The front support bushing (not pictured) simply unbolts from its cast-in mount on the finned front differential cover.
Since we didn’t have any luck tracking down bushings at any of the local parts stores, and there didn’t seem to be anything available as an aftermarket upgrade, we were stuck sourcing O.E.M. bushings from the local Jeep dealership. The two pressed-in bushings are designed to flex in a certain direction and need to be installed in the same orientation as the ones that came out -- with the flat of the center sleeve facing up.
Your best plan of attack for installing the new pressed-in bushings requires a ball joint press. If you don’t have one, most parts stores rent them, or you can opt for an el-cheapo Harbor Freight unit that we’ve actually had pretty good luck with. Once all the bushings are in, you’re ready to hoist the differential back into place and button everything up the same way it was unbuttoned.