W210 differential swap to W124 - PeachParts Mercedes-Benz Forum

kidMoBile · #1 01-11-2007, 11:36 AM

Does anyone know if a W210 rear differential (specifically from a 1999 E300 turbodiesel) will physically bolt into a W124 wagon, 1995?
Thanks.
Brian

Pete Geither · #2 01-11-2007, 08:45 PM

Could I ask,,,, why ?

kidMoBile · #3 01-11-2007, 09:37 PM

Okay.
I have a donor 300E 5-speed in my driveway. The wagon (115K miles now) is a third car.....I've driven it like a good soccer dad for 3.5 years, and now I want to start playing with it.
The donor has over 250K on the odometer, and that's busted! Obviously to do the conversion correctly, a rebuild is in order for the tranny and the differential, among many other things. The donor has a stock 3.07 rear (I was considering 3.27, but I think I'll stick with the "original" ratio) and I'll bet it's pretty well shot, but then again I could be wrong about that. The donor was driven into the ground, but the price was very right!
Potomac Pat has a brand new 3.07 ratio pupmkin listed on ebay for a W210 diesel. He has regrettably informed me, however, that it won't bolt in.
I figured if it fit I could pick it up and be that much closer to the goal. I guess I'll just have to get an assessment of the one I have or buy a lower mileage W124 unit.
Brian

Pete Geither · #4 01-12-2007, 05:13 AM

I am pretty sure the wagon has a 3.07 in it now. I know it is geared lower than the sedan.

t walgamuth · #5 01-12-2007, 08:35 AM

the benz diffs are very tough. unlikely that they are worn out.

tom w

kidMoBile · #6 01-12-2007, 09:48 AM

Pete:
I think my wagon is a 2.65. I've seen the number 2.65 several times in searches.

I just found a post from stevebfl where he stated that the rear of the W124 E320 (1994 and 1995, and perhaps 1993.....anything with the 217HP M104 and maybe the diesels, too) was 2.65 in either wagon or sedan form. The older wagons with the M103 had the higher ratio differentials: 3.27 in 1988 and 1989, and then 2.87 in 1990 thru 1992.

http://www.peachparts.com/shopforum/showthread.php?t=14825&highlight=wagon+2.65

Tom W.:
I know there's a possibility that the differential on the car is fine, but unless it was replaced at some point, it has nearly 300K miles on it or better. And by the looks of things, quite a few of the last couple K miles were very hard miles. I got it running and drove it down the street. Got it into 5th gear barely....I was going 35 mph and the car was just about to shake itself apart. Over all the noise and play in the drivetrain (flex disks are shot, differential mounts shot, motor mounts, tranny mount, all suspension rubber completely shot) I couldn't tell what was going on with the differential. You may be right and it might be fine. I'll have to take it somewhere and have it opened up to really find out.

I want to do the swap correctly. I want to have this car for 200K plus miles, perhaps another 5 years or more. The last thing I want to do is just toss the parts into the wagon and see what happens. I'm going to replace everything I can and rebuild what I don't need to replace. I want the car to perform as if this were a factory build when it's all said and done. The idea of having to do something twice because the part is malfunctioning is very unpleasant to me. So chances are, I will be installing a reconditioned differential in the wagon. And if I could buy a new one for a reasonable amount of money, then I figure I would come out ahead in time and hassle saved.

Brian

ke6dcj · #7 02-08-2007, 09:24 PM

I have a 3.07 diff for a W124 that will swap right in, assuming you don't have ASR on your wagon.

PM me for a price.

BTW: be sure to swap over the speedo so the diff ratio matches.

What are you going to use as a flywheel ? You can't use the 300E 5-speed's flywheel as it doesn't have the segmentation for the wagon ECU (HFM) pickup, unless you fabricate the segmentation windows or pull them off a dual-mass flywheel.

:-) neil

kidMoBile · #8 02-09-2007, 08:35 AM

Hi Neil:

No ASR. I will definitely send you a PM for a price this weekend. Are you running a 3.07 in your wagon now?

I'm going to do the same thing that Maddog did when he put his car together. Except he did the work himself on his flywheel.....I'm going to bring it to a good machine shop. I'm going to either use my original auto trans segments (can I use them?????) or just buy the same auto trans flywheel at a junk yard, have two segments cut off (I wouldn't know which end of the torch to use myself) and get them welded to the 86 manual flywheel at 4 and 8 o'clock, then have the 86 manual's 6 o'clock segment removed and get the whole thing balanced. As you know, it's the only thing standing in the way of getting a 5-speed behind the M104. Price shouldn't be terribly high.

I figured that our auto trans flywheels have the segments we need. We don't need to find a dual mass for donor segments. Am I wrong about this?

As you probably know, we can't use a dual mass unit because the trans input shaft was a different length on the 300E manual box vs the SL's manual box. Not that I'd want a dual mass unit anyway. My brother in law tells me that they are a common failure point on late 80's BMW's when pushed hard.

I know you like to keep things as OEM as possible on your wagon, but it looks like some fabrication may be required here. I'm good with it. Several people other than Maddog have done this too (190revolution.net)

Brian

ke6dcj · #9 02-09-2007, 10:04 AM

Quote:

Originally Posted by kidMoBile

I figured that our auto trans flywheels have the segments we need. We don't need to find a dual mass for donor segments. Am I wrong about this?

As you probably know, we can't use a dual mass unit because the trans input shaft was a different length on the 300E manual box vs the SL's manual box. Not that I'd want a dual mass unit anyway. My brother in law tells me that they are a common failure point on late 80's BMW's when pushed hard.

Brian

Yes, I'm running the 3.07 and I love it for the city. A little high for freeway cruising, but oh well.

I don't know if the automatic's flywheel has the segments, but it must have them in order for it to work.

I didn't know about the 300E's input shaft not being compatible with the dual-mass flywheel.

FWIW, I believe the 1991-1993 190E 2.6 with the 5-speed tranny came with a dual-mass flywheel.

So it all depends on the donor tranny.

Personally, I'd like to put in the 5-speed close-ratio from a 16v, but for everyday use, it probably won't be great. I hear the 300SL's box is the way to go, but I just can't source one.

:-) neil

BTW: I've never had a 2.65 diff, so perhaps we can swap my 3.07 for your 2.65 ?