UPDATE
 

Ok it's been awhile..

Today was the day!! I got the car on stands and pulled the 2.65 diff. I am in the process of switching over the axle flanges from the 2.65 to the new diff. It turns out I need to get a couple new seals since the new diff didn't use them with that ASR stuff on there. The 2.65 diff has metal shavings in it, so I am sure it's toast. I dunno if it can ever be rebuilt or not. I would prefer to have a good 2.65 in my parts bin, it sorta goes with my 300D transmission.

I do have a question, and I hope the people with the answers are subscribed to this thread. Should I used the axle shims from the old 2.65 diff on the new ASR diff with my old flanges? I know it sounds weird. The new diff didn't appear to have a shim, I have only pulled the 2 rights off.

I has a suspicion that the new diff(forgot the ratio but it's in the thread) will be too low. I think I will go from one extreme to another. I may end up with a granny gear :eek:

I just have a gut feeling that 3.07 is the ideal ratio.

I'm using a 3.07 in my 190D with 2.5T engine, "diesel spec" 5 speed, and 225/50/16 tires. It is a very nice setup. The diff came from an '86 300E.

Ya I'm using the 2.2(om601?) transmission. I may swap the gasser tranny into it since the diesel one has a 2nd gear bite at times. But it could be caused by me wanting to downshift into 2nd while going too fast because of the 2.65 diff, or something like that:cool:

Anyway, do you have any stumbling from a stop? That is my problem with the 2.65, but once it starts reaching boost rpm's it takes right off.

I drove on the highway yesterday for the first time in months. I am speed limited to 55mph because the old diff(hope it's not a wheel bearing) will whine and vibrate at anything faster, the snow tires on it kinda hide what its doing at 55. But those highway speeds really reinforce the need for a shorter diff ratio... I went to 5th for poops and giggles and was turning something like 1550 rpm :eek:. I think maybe anything but flat terrain at that rpm would lug the engine.

I think I would like to see 2500ish on the highway in 5th. What are your numbers?

I had another 190D 2.5T that I put a gasser 5-speed in with the 2.65. It was VERY sluggish off the line. A subsequent owner put a 2.88 in it, and said it was much better.

With my current 2.5T and diesel spec 5-speed, with the 3.07 rearend, there is still a big step from 1st to 2nd, but it's much better than with the 2.65. I think the main issue is the ratios in the diesel spec tranny. 1st is lower, but I believe that 2nd is the same in the diesel boxes.

The gasser transmissions may be a little more "close range" in terms of the spread between 1st and 2nd. They also have a slightly "taller" 5th gear compared to the diesel spec trannies.

Anyway, 2500 rpm gives me right at 70mph in 5th gear with this combo and 225/50/16 tires.

SteveM.

My BIL's 2.5T 5-speed has a 717.411 tranny and 3.27 diff, and IMO it's just about perfect. I would not want 3.07 or taller gears. You can't really use 5th gear until at least 55mph without lugging the motor.

1st gear is 15mph at 2500rpm, 30mph at 5000rpm redline
2nd gear is 25mph at 2500rpm, 50mph at 5000rpm redline
3rd gear is 39mph at 2500rpm, 78mph at 5000rpm redline
4th gear is 55mph at 2500rpm, 110mph at 5000rpm redline (estimated)
5th gear is 72mph at 2500rpm, 142mph at 5000rpm redline (estimated)

I didn't test it past ~90mph. Note that the gearing in your specific tranny will vary... most all the MB 5-speeds are different. The above data is for the 717.411 only!! Speedo accuracy was verified via GPS, stock tire diameter.

If using a 5-speed that doesn't have an overdrive 5th gear, then 2.65-2.87 diffs would be fine. If it has the 0.75-0.80 overdrive, 3.27 is perfect, and 3.07 would be as tall as you'd reasonably want on the street. For the record, the factory 2.5T (124.128 Euro with 5-speed manual) came with 3.46 gears. I can't imagine trying to drive one of these with 2.65 or 2.87 diffs. First gear would be stupid tall and 5th would almost lug the motor even at 80mph. Freeway fuel economy (on flat roads) would be great but the car would be miserable to drive.

:stuart:

OK Dave, I'm going now to the dealer to get the flange seals.. and perhaps the fancy MB sealant. I hope to plop that new diff in today, although the nagging has already started so I might have to help clean the house first.

Can you give me some info about the shims? The 2.65 appears to have shims and the new diff does not(I've only removed the right side off both). Should I use the 2.65 shims on the new diff?

Thanks

PS: What is a BIL? Only thing I can think of is "Best Friend in Life", or you have a "partner" named Bil :P

The shims for the axle stub flanges are for the side to side play. They should be adjusted so the flange C-clip can just be inserted without side pressure, i.e. so the axle flange moves side to side (in/out) less than 1mm. That's it.

BIL = Brother In Law.

:zorro:

Ok.. There is just something I love about going to the dealership. The one I go to is very nice and is complete with employees with German accents. I always go to the car wash before pulling any of my MB's onto the dealers lot. Guess I'm kinda odd. I also love the way OEM parts come with MB stickers on the packaging. :rolleyes:

Anyway, $6.25 ea for the seals. Not too bad considering that with shipping I would have paid more to buy them elsewhere. They did not have that fancy blue gasket sealant, so I guess it will be black RTV to the rescue.

I'm just going to throw this diff in and bolt up a stock 300E rear DS with a manual W201 front. I will look at my selection of used flex disks and pick some decent ones to use. Once I drive it for awhile, I will decide if I like the ratio or not. After which I will drop the sub frame and replace all the old suspension stuff. I may even POR-15 the subframe and diff.

The end goal is to switch the driveline back to the larger '87 300D stuff. But then we get to revisit the proper tools needed to swap yokes... not to mention the tools needed for the rear suspension replacement. Hopefully someone around the forum has the tool to borrow.

Dave, I don't know if I will be able to resist the urge to NOT spray the inside of the diff with brake cleaner. I'm rather OCD and just love to clean stuff with brake cleaner. My concern is that I've had these diffs open several times now, anything could have fallen in there. I have kept them bolted/covered up, but my work space is a picnic table in my backyard. And as of yesterday they have been rained on once. So the temptation to spray it with brake cleaner might be too much to resist. If I do it.. I will avoid hitting the bearings directly. I would feel better with a blessing or something else.

Still cornfused...

Do I want to use the shims from the 2.65 on the 3.69(?)...? I will keep them on the same sides.

PS:
Do I need to put some sorta "grease" on the new flange seals where they mate to to half shafts?

Use a rag to wipe out any gunk, oil, residue, etc from inside the diff. A mild solvent or degreaser on the rag would be fine. I wouldn't use brake cleaner though, it's probably a bit aggressive, and may take off the white/beige paint from the inside of the diff (you'll find that under the layer of brown).

For the shims, you use whatever shims are needed to make the axles have approximately <1mm end play. You won't necessarily use one set of shims or the other. Whichever works better is what should be used. See attached PDF file for the specific FSM instruction on this. The shims are available in 0.05mm thicknesses. I believe formal spec is 0.03-0.30mm end play for the axle flanges (as found elsewhere in the FSM).

I'd put a thin smear of clean gear lube on the axle flange, where the seal rides, but that's it. No grease.


:boat:

Not quite done yet
 

Well I got a late start today because of the aforementioned nagging :cool:

I did in fact go all brake cleaner on the diff. The interior paint/coating stayed intact and it looks pretty nice. I also got to see the random colored paint that MB used on different areas of the diff.

Shims: I didn't use any. I got no play on the right flange and very very little on the left.

So let's see... I'm of the opinion that one of 3 things are questionable in the OM603/W124/5 spd swap. 1: The engine sits farther aft than the 602(the other popular 5 spd swap). 2: My diff sits too far forward. 3: The 300E aft DS and W201 manual fwd DS are just too long for the W124/603/manual. The w201/w124 "combo" DS seems roughly 1/2-1" too long. The only way to make it fit was to drop the exhaust, connect the aft flex disk, PULL the carrier bearing area away from the car about 1.5 feet while wrestling the fwd flex disk in place, and finally push the carrier bearing into place. And I mean PUSH with such a force that the flex disk collars "snap" into the recesses of the yokes. Initially the center carrier bearing was deflected against the carrier. But once I fully seated the flex disks/collars the carrier bearing unloaded a little. I'm still a little apprehensive about any excessive loading of the pinion and output shaft bearings. I also had to remove the rubber dust cover from the aft shaft spline. So for my application, and perhaps all w124/603/5 spd swaps, a shorter fwd shaft would be ideal. Remember, I have a custom fwd DS that I was using with the larger DS setup. I will go back to that custom setup once I settle on a transmission and diff ratio.

Everything is bolted up. Only thing left to do it connect the half shafts abd fill the diff with fluid. Then I can go for a drive :eek:

Sounds like excellent progress. I have no idea about the cause of mis-matching the front and rear shafts... there are a lot of possible variables there.

So, you actually swapped the "guts" of the rear diff instead of swapping the housing and all?

Can't wait to hear how it drives. You are using the 3.27 diff. ratio, correct?

SteveM.

I did not swap innards, just output flanges.

http://www.w124performance.com/image...m/flanges1.jpg

I'm using a 3.69, IIRC. I thought I was getting a 3.27 but as it turns out I got a more complex 4-matic diff. Not a bad deal.. I got it from a forum member who delivered it to me. If I do keep this ratio I'm gonna need a speedo head.

I am getting ready to go work on it now. Can't seem to find torque specs for the halfshaft to diff bolts. Guess I will use threadlock and the standard German torque spec.. Gudentight

Cool, so you now have 3.69 limited-slip! Make sure you use LSD-compatible fluid, or you may de$troy the L$D clutche$.

:stuart: