I doubt if I will test my '87 near its limit ever, unless I drive it thru New Mexico someday (I love to WOT my 1232 300TD's thru there!) can't afford a Calif speeding ticket and I have a clean record over 25 years no tickets.
I guess I am losing reflexes too, or less adrenaline to spare
I did some checking and found the '87 300DT to have this diff: RATIO 1:2.65
I agree its not worth losing some acceleration to get a higher top end because no one in their right mind drive close to the limit in that car, but I am sure there are those on the 'Forum that have tried!

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'95 E320 Wagon my favorite road car. '99 E300D wolf in sheeps body, '87 300D Sportline suspension, '79 300TD w/ 617.952 engine at 367,750 and counting!

Hello,
Raise the back of the car and with both rear wheels off the ground, have an assistant hold one side stationary and spin the other, then repeat with the *other* side. Bad bearing will rotate with roughness, and pulling outward on the tyre will show up excess endplay in that hub.
I would suspect wheel bearing, as the rear bearings will not change the *tone* when the car is steered. I had the same thing happen on a friend's W124 300E 4-matic and my brother's Citreon AX(small fwd). In both cases it was a rear wheel bearing. Diff noise will vary with speed AND load, meaning that when you accelerate, there will be more noise that will completely disappear on coasting.
Always check the simple(read cheap)stuff first.
have a good weekend.

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Nachi11744

I will go to an indi and have a diagnosis.

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1992 300D 2.5 turbo diesel. 319 k miles.
124.128 chassis, 602.962 engine, 722.418 tranny.

Haven't followed this thread for a while, but based on what "nachi11744" mentions about the diff making more sound while accelerating and no, or little sound while lifting off your foot from the accelerator, I would have to suspect my differential is what I'm hearing.

Also, would it not be a good idea to re-pack wheelbearings anyway? My car has now 240K and as a matter of regular maintenance be serviced now if not done so in a while?

Steve............

Rear wheel bearings are permanently lubricated sealed double row ball bearing units, they cannot be serviced. Replace if they go bad (usually grind, groan, or thump). By the time they get play in them, you've noticed other symptoms as well!

Dif noises usually change with load, but not always, depending on what is wrong.

A professional hands on opinion wouldn't be out of place here, you are talking some bucks.

I don't know if you could get a lower ratio that 2.65 for a diff, that's the lowest I've ever run across! Our old Oldsmobile was 2.76 -- talk about a scary car! 90 mph upshift into third on the automatic, top end around 130, and NO brakes to speak of.....

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

Hmmm....sealed rear bearings? Now you know why I call it a "hobbie" well I do think now more than ever it's my rear-end, and not rear wheel bearings!

Anyway, I have gone to Mobile 1 diff oil, and is all I can do for now, if ever it should sound louder, I'll become concerned at that time. If I were planning a drive cross country, I'd definitely have it looked at!

DDH,

Yep - we have 2.65 ratios. Official top speed is 129mph according to the TDM, although I was only able to coax mine to a GPS-indicated 125, with fat 225/45/17 tires not helping any. I wouldn't mind a 2.82 ratio, or even a 3.06, except on the highway. The lower ratio should make it a lot snappier off the line though. Now if we could transplant the 722.5 tranny (5-speed with overdrive) from the early R129, along with that lower ratio, that would make a *fantastic* combination! I actually looked into doing this a while back. It is possible, and it will work, but the cost is outrageous (several thousand dollars, even with used parts) and it would be a huge job.

I'm more interested in coverting my open diff to limited slip, even with the stock ratio. I hate the lack of limited slip! Sadly that's not cheap either, I think ~$1000 to have an open diff converted to LSD.

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Dave
Boise, ID
Check out my website photos, documents, and movies!

My car has the symptoms of a noisy rear end...only makes noise when accelerating or crusing at 35 or above. Its a definite whine...dad agrees on the problem. Anyway, my question.
Are these rear ends servicable, IE, can they be shimmed, adjusted, whatnot back into specs? I know this is by far no easy task, but a friend of mine in portland is a transmission only guy and would be up for the job if it is possible.
Anyone know?
All else fails, anyone got a rear end laying around?

The usual wisdom is that unless you have the special tools, and have successfully repaired a MERCEDES differential before, don't bother trying. (The same goes for your mechanic friend.) Just get a good used diff from the salvage yard and swap the whole thing out. It's a lot easier and often a lot cheaper in the long run...!

Yeah.
I don't doubt his abilites becuase he specializes in non-american made transmissions and sure knows his stuff. He is the local guy to go to for hooking odd engines to odd transmissions, and stuffing them in cars they normally wouldn't fit it. I will confer with him and see what is up. It can't hurt to atleast try if I would just have to replace the whole thing anyway.
I dunno...guess we will see.
I am all for tinkering and trying...
its the best way to learn, even if you have to try 5 times, mess up every other one, set your clothes on fire, or bathe in some non-standard fluids.

It can be done, but be prepared to spend some time and/or get some special tools.

Setting pinion mesh is rather difficult, I've been told, as it's set by crush washer, not shims. Otherwise, fairly standard. However, if you've not done a differential before, be perpared to do it several time until you get it right.

Most important, don't install it and drive it until you have verified ALL the gear mesh patterns with spotting blue -- if you are off, you can ruin the gears in a very short time!

Also, if you change the pinion seal with the diff in the car, please, please, don't roll it around with the nut off! If you do, the pinion will retract and you can snap teeth off the ring gear. This is a big hassle.

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

Mmm very useful information.
I would have him do it, and watch from the sides...not do it myself and just mess it up. If it is sucessful, I could drop a post here with information, pictures, etc.
Anyone find that useful?