If I have to replace my rear differential in a year or two which my mechanic says I may need to - I am starting to get a whine out of the differential - possible pinion gear - which one would be best to look for used?

I read other posts that said the 2.88 got better fuel mileage but came out of 1985 300D and 300SD or SDL cars.

I also read that most had the 3.07 differential. I have a 1982 300sd and am not sure which differential is under there. I am not as technical as some of you guys and gals, so please forgive my ignorance.

I have a 300TD wagon whose body is rusted out. Could I use the rear end from it in the 300sd? I am guessing not since it had all the leveling stuff underneath.

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1982 300SD Light Blue
2002 Honda Accord SE
1974 Toro Wheel Horse Tractor
2000 Toyota Tundra Pickup

Bottom left corner of the differential (viewed from rear) has a part number and ratio stamped into it.

Which one is best for you depends on what sort of driving you do.

__________________
Proud owner of ....
1971 280SE W108
1979 300SD W116
1983 300D W123
1975 Ironhead Sportster chopper
1987 GMC 3/4 ton 4X4 Diesel
1989 Honda Civic (Heavily modified)
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Section 609 MVAC Certified
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"He who fights with monsters might take care lest he thereby become a monster. And if you gaze for long into an abyss, the abyss gazes also into you." - Friedrich Nietzsche

In case you want to try a cheap possible fix..... I had two different Toyota rear wheel drive cars which started to whine... it was getting louder over several thousand miles.... the cheap ( but great ) corolla wagon was like a drum inside... I was down to using ear plugs when driving it...
What I did was add a couple of the Slick 50 Gear Lube treatments to each of them... and within 500 miles the whine was gone... might have gone away on its own... but it was getting louder at the time I installed it..... I don't know... but this is a cheap try which won't do any damage if it does not work....
I would put in new differential fluid at the time I added this stuff just on principle...

Try thicker lube as mentioned or turn up the radio...

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Bill Reimels
Now down to one:
1972 300SE 3.5 W109 (Euro delivery)

I hate a whining differential! When they get that way the solution fro me has been swap another one int, hopefully it is not as noisy.
Differentials are relatively easy to swap, and the cost for one depends a lot on the sellers desires/needs etc and the mileage on it. I have been lucky on one and not so lucky on another, ie, one was a whiner.
My '83 had a noisy 3.07 std ratio and I found a low mileage '85 2.88 diff, it is very quiet and the performance difference is very noticeable and made the swap worthwhile. I recommend the '85 gearing for any turbos.
A 300D NA car will however show great benefits in lower rpm and better fuel economy with a taller ratio but only if not used a lot on uphill grades (even a little grade will cause the need for more downshifting).
1971 220 (gas) 4-spd manual and 3.07 diff 106441
1979 300TD w/ ’85 turbo engine and 3.07 diff 296650
1983 300D 243280 2.88 diff
1985 300TD 223470
1987 300D 262300

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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!

Don't worry about it.. in all of the diesels I've seen I don't think I've ever heard of one differential failure. They will whine for a very very long time without failing. Did you try chainging the fluid?

sorry to hijack your thread... i have a 300TD non turbo with a 3.46 diff... do you mean that i would feel a terrible loss in climbing capability if i install a 3.07 diff??.. i do mostly city driving.. but our club does have occasional out of town trips that has climbs that require some manual tranny gassers to stay in 1st gear... does that mean i wouldnt be able to climb those type of grades??


anyway, back to topic... i have to agree with the other posts here.. try a thicker viscosity and see if that removes the whine.... postpone the diff swap for now.. good luck.

__________________
Mike

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1975 200 - Sold (no pix);
1978 200 - Sold - http://www.pbase.com/hboy/redbaron
1979 300TD - Sold
http://www.pbase.com/hboy/greenwagon
http://www.geocities.com/hboy726/300TD.html
1985 230E - now my daily driver...

No you will still be able to climb nearly anything that you encounter, short of some trips to Yosemite that I would not recommend. Sorry I remember you are in the Phillippines, well if the grade is over 5% you might regret being there. If gassers are having problems then you better be behind them too.
it's just that you will sometimes have to drop down a gear that you wouldn't have to do otherwise or you will down shift sooner than if you had the higher ratio installed. The 300D NA has a lot of torque so it shouldn't be a really noticeable problem on flat roads unless you had lots of stuff to haul. Like the 1200 Lbs of ceramic tiles I hauled (twice). I made it 3 miles with no up hill at all.

Removing the whine is what you were after, so first try the thicker viscosity lube while you look for a low mileage differential of even the same gearing if that is all that comes up. I saw a 300TD NA in a wrecking yard with only 70K miles on her, if I were smart I would have bought the differential and the steering box, Dumb me I let it pass.

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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!

I didn't think I could do the rear wheel bearing properly after looking at the factory service manual. So I am letting my mechanic do that. They are going to change the fluid at no charge. The differential may not whine after that. With all that bad wheel bearing noise, who knows how anyone could hear the differential! But he is reliable and the best with the older cars. He told me it would go several more years, but I figured what would it hurt to find a diff. and put it in the barn till I need it.

I am putting back in the Lubrication Engineers LE Monolec 90 weight diff lube. It is what the Mercedes dealer has used for 30+ years and I talked to the company representative/engineer and they said it is used by long haul truckers who use LE motor oil too and many have 1,300,000 miles on thier rigs running coast to coast with no engine, differential, or transmission overhauls (oil analysis was done). Local corvette shop uses it here and swears by the stuff in its race cars.

http://www.le-inc.com/index2.cfm
http://www.le-inc.com/Literature/LE%20News/answer.pdf
http://www.le-inc.com/Literature/Misc.%20Literature/ALMASOL%20Flyer.pdf

Found a 2.88 diff for $200 local with 155,000 miles. Is that good?

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1982 300SD Light Blue
2002 Honda Accord SE
1974 Toro Wheel Horse Tractor
2000 Toyota Tundra Pickup

If that rear end lube is used by race cars you might get by. Most important is probably the viscocity of course with any replacement. Now the quantum leap and know it really sounds stupid. Someone did remove the plug and check the current level? Stranger has happened and assumed someone has. But the devil made me toss this in. The answer to your rear end swap probably lies in if your car was really struggling on the hilly terain on your outings. If it did pretty well I would not hesitate to go the other ratio. Also you might want to check your turbo boost properly and set to specs if out when you change the rear. At that point the car might even be better than with old ratio. Just some thoughts. Once you have aquired a replacement differential you might want to add a little graphite to the old rear end oil after changing it to help kill whine if it persists. I think it replaced stuffing with sawdust years ago. Do not know if detrimental or not. Perhaps someone can chime in that knows more about the graphite.

turbodiesel,

How long does noisy differential last?
Mine is noisier than engine during coast, and during deceleration. A mechanic says the differential noise does not affect safety now.
1992 300D, 248000 miles.
I want to keep the car for more than 5 years.

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