Would the 300SL diff. fit on the 300CE? It has the same ratio as the european 300CE, so i assume its probably the same unit? Anyone know if they are compatible?

Your differential gear ratio is probably a 3.06:1. What is it that you are trying to gain?

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Steve

1992 300CE Sportline Sophie
1990 300E Emma - in the family
1979 240D Josephine - sold, but not forgotten
2004 Pacifica AWD

http://web.mac.com/dakota/Mercedes/Home.html

I'm looking for 3.69

3.69 is used in E280 and E320 and SL that come with 5 speed automatic.

Right, the SL is the easiest to find, at least on Potomacs site. The problem I'm having is figuring out if the SL diff. is only ASR or a different housing or something and it wouldn't be real easy to just mount it on up to the 300CE.

here's a little reference data... happy hunting:

http://www.w124performance.com/docs/mb/other/differentials.pdf

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

thank you, I think I can use that to find my answers.

Man, you'll get about 10 miles/gallon and run 4000rpm at highway speeds! (You'll have a quicker 0-60 though.) Should bolt up...

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Mike
-W126C 560SEC 040 Black
*6.0L AMG M117 32v Hammer
-W163 ML320 Brilliant Silver
-W124 300E Pearl Black

Thanks for the reinforcement. My gas mileage sucks anyway, it might get better, i have this new commute through the mountains, uphill. The europeans get all the good stuff, its my turn.

I wouldn't go past a 3.06/3.07 rear end with a 4 speed auto. Now if you want to do the 5-speed tranny conversion, then yup a lower ratio would be awesome, if you could get enough rubber to hook up at launch. The 5-speed auto tranny swap is a bolt-in but very expensive because the parts required are rare, and therefore very hard to located used in salvage yards... and new parts from the dealer would be $$$$. I have a 2.65 in my car and want to upgrade to a 2.87 limited slip this winter, if all goes well.

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

I would not recommend the 3.69 without the overdrive 5-speed box to match. Here in Australia all our 300CE-24, 320CE and E320 coupes came standard with the 722.5 (5-speed auto) and the 3.69 rear axle ratio. It is common to find some of these cars retrofitted with the 722.3 (4-speed auto) due to the failure of the 5-speed and the expense to repair it. Often the rear axle ratio has not been changed (to 3.07) to suit the auto without overdrive. The result is silly engine revs on the highway. Sure the 3.69 gives great acceleration off the line but you need the overdrive to match. Even my old 350SLC (3.5 M116 V8) runs silly revs on the highway with its 3.47 rear axle ratio (needed due to 3-speed auto).

My father owns a 124 '93 E320 coupe which still has the 5-speed auto with the 3.69 diff and it is very quick when 1st gear is used (normally starts in 2nd). The biggest problem is getting the power to the road (does not have ASD/ASR or limited slip diff). In anything other than dry conditions 1st gear is next to useless. If you do get the power down in 1st gear the coupe is impressive for a six and the fastest thing we got in a W124 (unfortunately there were no right hand drive 124s with the V8).

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107.023: 350SLC, 3-speed auto, icon gold, parchment MBtex (sold 2012 after 29 years ownership).
107.026: 500SLC, 4-speed auto, thistle green, green velour.
124.090: 300TE, 4-speed auto, arctic white, cream-beige MBtex.
201.028: 190E 2.3 Sportline, 5-speed manual, arctic white, blue leather.
201.028: 190E 2.3, 4-speed auto, blue-black, grey MBtex.
201.034: 190E 2.3-16, 5-speed manual, blue-black, black leather.

Sounds like fun

I intend to get a 5-speed or adapt a 6-speed manual eventually, depending on my ambition, but in the meantime, I want some acceleration. i am debating, is there a way to calculate, scientifically or otherwise, where the power would go, like when would the car be slower, besides obviously top speed. I dont know if the really short is best for 1/4 mile or the really tall, or soemthing between. Right now, its too tall, way. Feels like its towing a trailer.

The correct size tyres for a W124 rotate approximately 810 revolutions per mile. At 60 mph (1 mile per minute) the wheels will therefore be turning at 810 rpm. If you multiply this by the rear axle ratio of 3.69 (and allow a small amount of slip) you get approximately 3000 rpm. In top gear with a direct drive (1:1) ratio this would be the engine speed. Therefore at 120 mph the engine would be running at about 6000rpm (still below the rev limit for an M103 or M104). Since a 300CE could not reach this speed over the 1/4 mile this would suggest that the 3.69 rear axle ratio would not be too short over this distance. With the 3.69 ratio the maximum speed of the vehicle would be restricted by maximum engine speed (130 mph would result in 6500 rpm). When compared to say a 3.07 or taller ratio the maximum vehicle speed would probably be reached before maximum engine speed. If 6000 rpm could be reached with a 3.07 this would equate to about 145 mph (would depend on engine power versus drag at those speeds). The 5-speed overdrive transmission with the 3.69 rear axle in 5th gear would result in about the same engine speed as a 4-speed with about a 2.95 rear axle ratio for the same road speed.

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107.023: 350SLC, 3-speed auto, icon gold, parchment MBtex (sold 2012 after 29 years ownership).
107.026: 500SLC, 4-speed auto, thistle green, green velour.
124.090: 300TE, 4-speed auto, arctic white, cream-beige MBtex.
201.028: 190E 2.3 Sportline, 5-speed manual, arctic white, blue leather.
201.028: 190E 2.3, 4-speed auto, blue-black, grey MBtex.
201.034: 190E 2.3-16, 5-speed manual, blue-black, black leather.

I see. Thank you for that