99 Jeep Grand Cherokee, howling

[SaturdaysGS]

My dad has a '99 Jeep Grand Cherokee (4.7 V8), that is in OK shape, needing only new shocks (OE at 125k), tweeters (blown - common problem), headunit (FM station = little to no reception), and the evap code taken care of (now emissions exempt til 09) thanks to it.

One of the MAJOR annoyances though, since its his daily driver, is that the rear end howls, BAD. It is definately coming from the rear end, and have heard it to be somewhat of a common problem.

What I would like to know is that, A) what is the problem, and B) approximately how much would it cost to fix? Obviously depending on how involved it is, it may not even be worth it (99 w/125k on it).. but if its something that could just lock up anyday, well then it would be vital to get it taken care of.

Thanks
-Nick

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[Primalzer]

A. Is it out of alignment?
B. Are the tires ruined because of A?
C. Is it coming from the rear diff?
D. Are the tires out of balance?
E. Maybe the tires are out of balance/ ruined because the shocks?

 

[SaturdaysGS]

A. Is it out of alignment?
B. Are the tires ruined because of A?
C. Is it coming from the rear diff?
D. Are the tires out of balance?
E. Maybe the tires are out of balance/ ruined because the shocks?

A. No, I just had it aligned at work.
B. No
C. Yes
D. No, just balanced them
E. No, they arent cupped, but the shocks do need replacing, IMO, It rides "funny" compared to other Jeep Grand Cherokee's I've driven at work.

 

[Primalzer]

Is the diff a posi or trac loc type, or does it have a locker, or is it open?

 

[Dasfinc]

IIRC our old roomates 6 cyl 95 Grand Cherokee does the same thing, and has been doing it for quite some time.

 

[Primalzer]

Must be a Grand Cherokee thing, because my family had a 92 Cherokee for 10 years, and it never made a howling noise, just about every other noise you can think of...

 

[Bob Kazamakis]

have you checked the fluid out back? its not hard to pull a rear cover. I would also check the gears for excessive wear and play.

i bet it just needs a fluid change

 

[skeezer]

give it a bone

 

[ChrisRac]

Maybe its the supercharger....

... oh wait, you said rear. Wheel bearings?

 

[WhiteDevil]

check the tire pressure and inspect for abnormal wear. rears should be the same all across the tire tread, if its lower on the inside or outside you might have some internal axle issues.

 

[SRT41320]

if its the actual rear-diff - its prolly the pinion bearing or side bearing - causing pinion-to- ring gear mis-alignment. if no damage to any parts and only need to replace bearing it should only be a couple hundred bucks... if the spider gears are shot, ring and pinion are shot, etc. the price goes up froom there.

 

[SaturdaysGS]

Is the diff a posi or trac loc type, or does it have a locker, or is it open?

No idea. I assume open.

I'll check the fluid soon. Its probably never been touched.

Its not the tires/tire pressure. It did this with the tires we bought it with, and then with the new tires we put on it. The tires are wearing great.

SRT, if there is damage to the other parts (obviously not talking about the bearings as it seems like those are shot), would it be noticeable?

 

[Turbocharged400sbc]

first and foremost use a magnet to check if the rear axle pumkin is aluminum, if it is the only way your gonna fix it is to get a new rear axle, the alum centersection dana's are notorius for carrier/pinion bearing issues, the best fix is an iron housing.

i've put new bearings in 3 of those housings and only one didnt have any further problems, the other two had to have had the housing flex enough to missalign shit real bad, since the carrier bearing surfaces showed that the races had spun at least a little bit... of course i had to fix em (without the high cost of a whole new axle that jeep wanted $$$ fer) it's kinda funny how common the aluminum dana centersections failures are... aluminum wasnt meant for axle centersections lol.

 

[SRT41320]

yes and no - ive seen spider gears that you would think would make noise never did and ive heard the wierdest noise coming from just a bad bearing - best thing to do is pull the cover and check the fluid and inspect everything...