I read through some of the posts and want advice in my situation.

I recently bought a 2004 Coupe a few months ago with 15K on it - mint condition with no accidents. The car seemed to have no real issues except a CD player that skipped on bumps, a bad speaker and the common driver side squeak on the bulkhead.

I have put 5K on the car and last week I pushed it up to 80-90 quite a few times on the highway. It was then I noticed a differential sound with light pressure on the accelerator - I am pretty sure it is the differential based on the sound and symptoms. I probably have one of the dreaded bad rear ends and it is just showing up now. At 65 to 75 I do not think the oise is present but I am sure it will soon become evident as time passes.

I will review the car history when I get back home to see when the car was actually first sold..I am the third owner and a dealer was the second owner. It was stored for quite a while.

What are my options since the warranty has probably expired!!! I was thinking of writing to Chrylser and explain the issue and offer a payment for labor if they supply the part...yeah..fat chance.

If I went with a new differential what are my options and costs? 2K would not upset me but more would make me think more about that Mustang 5.0 I originally was looking for. I don't need this car for commuting so a long repair is not a problem either. Until I drive it some more at 75 I don't know if it is a problem but it will always be in the back of my mind.

Thanks, PDW

 

Many of the Crossfires have a quiet purring sound from the diff with light acceleration all the time on the highway.
Mine does and has for five years with 86000 miles now.
New diff oil put in at 65000 and the old stuff looked fine still.

Don't concern yourself with this IMO

 

need a lot more info if you want our help...a noise just doesn't get it... Any vibration along with the noise? Could be a bearing in the driveline...or a wheel bearing, or a......etc etc..... Just need some info here.... It could even be tire noise.....

 

PDW, remember that your right ear is only about 3 ft. away from the differential. You're going to hear every sound it makes. On a 5000 mile trip, you could become a little more "sensitive" to its normal operating sounds, that you may normally over look on shorter drives.

 

Check the fluid of the differential, what does it look like, thats the deal often. Woody

 

Thanks for all the info...I am out of town but as soon as I get back tonight I will drain and refill the differential and take a picture if it looks contaminated.

I have read conflicting info on this site as to the viscosity owners are using in the rearend. Stick with the owners manual or is there a better alternative?

Thanks,, I feel a little relieved knowing others have some noise and high mileage

 

I'm obviously not aware of the actual sound but it could be a bearing, either inboard or outboard at the wheel. If it is inboard in the diff then it will get worse and will alter the wear pattern on the gears and after that the noise is permanent even with a new bearing fitted unless a whole new gear set is fitted as well.
CV joints also fail, so if you have a real problem it should be looked at now. Tough call.

You can of course turn up the radio until it is screaming so much that you cannot stand it, that's what my wife did in our Mustang.

 

I've got the same problem. 2004 with 96,xxx miles... Haven't figured it out. Assume it's inside the diff, but going to get wheel bearings changed first. Will look CV joints over while doing so.

 

If memory serves, we used 75w90 Mobil1...

 

Apparently the owner's manuals changed for 2005. My 2004 manual recommends 75w140, and I believe all later manuals call for 75w90. I went with Mobil1 80w90 first, then read comments about Royal Purple helping quiet noisy gears, and changed again to RP 75w140, but no change in the whine/ring. Apparently MB changed their minds, so I would recommend staying with the later spec of 75w90 (or 80w90, which I think is more readily available).

Check your rear axles. Apparently slip fit or bolt in (differential side) were used, with the slip fit being in later production. Most documentation says 2004 has bolt in axles, but mine and at least one other member here have slips. (my car was built 11/03) I've seen low mileage diffs on ebay (slip fit) going for as low as $300 shipped. I don't expect bearings to make a difference in mine, and if everything else checks out, I will probably be buying a late model year, low mileage diff myself... This is my daily driver, and I get tired of working on it. If it's down, I have to drive the wife's mini van. My lifted K5 kills me on gas, and I won't take my '67 Belvedere into crazy morning traffic. I see someone get rear ended about every other day.

 

67 BELVEDERE! I'd like to see some photos of that.

 

Installing a Magnaflow exhaust is another option.

 

I noticed mine had a slight "whine" on the turnpike when lightly accelerated from 70-75 mph.. just ever so slight..somewhat "higher pitched".. that was 8 months ago.. now at 95K on the car.. and hasn't changed or been an issue..

 

I put 400 mils on it traveling back home (hit 20,400 miles) and listened to it. It has a slight high pitch whine once I go over 73 to ?? with a slight pedal touch. Below 73 it is quet. If the radio is on you would not hear it. It's possible it has always been like that and I just never noticed it like the previous posts suggests.

I flushed the fluid and it was a blackish grey color. I saw no indication of metal particles when I filtered it. I did notice that it had just a a tad over a quart when I measured it (not the 1.4 quarts the specs stated.) I refilled it with 1.4 quarts of Royal Purple 75W90. I'll see if anything changes. This was the first rear end fuid change on this car - underneath everything looked like it just rolled off the line and the filler plugs had never been removed before.


QUESTION...Based on my vin#, my car was built in 04 , production #19,368.
What was the reference in regards to the slip versus bolted rear-ends??? I see no bolts on my CV axles and the driveshaft appears to be bolted to a diferential input shaft a few inches in front of the differential. Is this the bolted versus slip that the reference was made to?


Thanks

Now I need to replace the radio and blown speaker and fix the bulkhead squeak.

 

Sounds about like mine. Early production 04's had bolt on axles. The bolts you saw are for the flex discs. Need to check them for cracks. Really easy to change.

What speaker is blown? I have a spare right door 6". Haven't done any homework on the squeak. What's the fix?

 

With all these squeaks and whining from our cars I'm glad I'm a bit deaf. The only whine I hear when I speed is from my wife.

Seriously though, I cannot say I have heard any noises that I find unusual and I'm a bit picky. I have had a whine from a bad wear pattern on some old tires once and a bad grinding noise on this car at low speed also from a bad wear pattern. Tire noise is hard to pinpoint at times.

 

But when you had those tire noises it was all the time though, right? It wasn't just under certain throttle conditions, etc?

 

My noise is definitely the differential but it is not enough of a concern now that I see others have the same small noise with light pedal pressure.

My blown speaker is the door lower right. I am ordering a set of 609CS Infinity for $130. From what I read they are a great improvement and if I am ripping apart the door I am changing them all to new ones. I also had one of the tweeters act up once in a while so they are all going... $130 is a good price for the 609CS...upgrade to our current speakers...comes with crossover too for adjustments.

 

I don't want to steal the thread, but never pass up a chance to post pix...

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Still a work in progress. Need to get the top frame rebuilt, seats recovered, and bumpers straightened or replaced. Then decide on wheels. These are off an 80's Jeep XJ. 318 bored .020" over, Hughes Whiplash cam, Edelbrock Performer intake/carb, all blacked out, 727, 3.94 suregrip, dual Flowmasters (a bit loud at low RPM's, but smooths out very nice on the drive.)