Replacing my 230sl differential...

[waqas]

Note: this thread has been transformed into a rear axle/differential assembly replacement thread.

Greetings:
On changing the manual transmission and differential fluids in my recently acquired 230SL ('65), I found metal slivers floating around (and mocking me with their oily gleams). I've been dreading this, but what is the best way to approach this?  Replace the manual transmission and differential with good used ones? Try to rebuild? Run it until something gives? (of course, the transmission is already complaining with a nice warm hum, typical of warn gears; however, shifting is still extremely smooth).
If replacement/rebuilding is inevitable, I was considering using this opportunity to replace the 4-speed with a 5-speed. How easy is it to find a ZF? Which other MB 5-speed manuals fit? I also read about someone changing out the differential with another having a different ratio. Is this advisable if also changing to a 5-sp? What kind of expenditure am I looking at here? (DIY or not)
So many questions, so little time...

waqas
--
1965 230 SL Euro, 4sp. man, dark green

[ja17]

Hello Waqas,
Don't count your old units down and out yet. Transmission noise will often times is caused by damaged or worn main ball bearings or a loose spanner nut on the gear cluster. The five speeds are very rare and very expensive if you can find one. In any case a transmission removal is in your future if you are experiencing noise from the unit.

The standard transmissions are not that difficult to repair. Many sedan era standard transmissions will bolt right up to your W113 but the first gear ratio is real granny on the sedans.

Change the differential oil and don't worry about it unless it gets noisy also.
Good luck, keep us up to date.


Joe Alexander
Blacklick, Ohio

[waqas]

Thanks for the re-assurance. Having changed the transmission fluid, I can attest to the fact that the previously apparent gear hum is noticably lower, although still quite prominent. Would it be helpful if I flush out the transmission a few times to clear as many particles as possible? Will I be ruining any refurbishable parts by continuing to drive it this way? Is there such a thing as a re-build kit available, and what does it typically comprise?

Lastly, perhaps it would be best if I leave the rebuild to the experts (the most I've done in the past is swap out transmissions on my old Honda). Would you recommend anyone in particular?

Thanks for all your kind advice!

waqas
--
1965 230 SL Euro, 4sp. man, dark green

[waqas]

In the interest of thread non-proliferation, it's time to resurrect this old thread. It seems my differential finally gave out (gave up?): as I was heading out of the house, I heard a thunk, and the car slowed to a stop (engine running). No gears worked. I peered underneath, and my drive-shaft was still turning (car was in first). As you can probably guess from my earlier posts, it seems that lack of oil over the years with the previous owner finally caught up to me.

My question is this: is there a differential rebuild kit available? I'll probably take the diff. and kit to an expert (I'm in Austin, TX), as I've little experience with such things.  If not, what are my options for a replacement? Which other MB differentials can I use?

Also, what other maintenance tasks would you recommend while the differential is out?

waqas
--
1965 230 SL Euro, 4sp. manual

[ja17]

Hello Waqas,
Sorry to hear about the bad luck.  It sounds like the splinned univeral in the differential sheared. These can be changed out, but the differential will need to be opened up and removal is probably best.


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The new part is very expensive. A good used differential is a good option. Good used univeral units can also be had. Most W111, W112, W108 sedans and coupes of the era had this type of differential. The 3.75 ratio of the 230-SL may be a little more difficult to find. However 4.08, 3.96, 3.69 and 3.27 are a lot more common. These will also have disc brakes on the rear also.
Locating a good used differential unit or the part is not difficult or expensive, let us know which way you wish to proceed.



Joe Alexander
Blacklick, Ohio

[waqas]

Hi Joe,
Thanks for the information. A preliminary search on the web has yielded little on where to get a used replacement. It seems the alternatives you mention might be my only option. Judging by John Livingston's recent experience --nicely documented in these pages, I might gratefully add-- I've a 'fun' time waiting ahead for me :-)

Regarding my current differential ratio, I'm not sure what exactly I have. It appears the rear axel/assembly may not be original (my drums have lug nuts and not lug bolts, and 113's had lug bolts on all four wheels, including the 230sl drums, as pointed out by Ray Paul of SL Classics on the phone a few months back).

Correlating the behavior in 1st gear with other 113 owners, I've a hunch it is higher than 3.27, and indeed, it may still be the original 3.75-- which begs the question: how can I tell? (lettering on the casing?)  I'm not necessarily in favor of changing to a 3.27 (I'm not a 'cruiser'; I do a lot of backroad driving; besides, I love that load roar). I suppose a reasonable alternative would be the 3.69 ratio. Which models were these fitted in?  

Lastly, would you be able to recommend any junkyard/dealers in your 'rust-prone' north who might have a reasonable donor waiting to lose it's rear end?

Thanks again and kind regards,

waqas
--
1965 230 SL Euro, 4sp. manual

[Naj ✝︎]

A pity that MB chose not to use a little magnet on the drain plugs to catch these floating slivers  :evil:
naj

65 230SL
68 280SL

[rwmastel]

quote:Originally posted by naj

A pity that MB chose not to use a little magnet on the drain plugs to catch these floating slivers

I've got a motor oil drain plug with a magnet.  I got it from Will Samples at S&S Imports (see our vendors list).  I never thought of getting one for transmission or differential.  Are they available?

Rodd
Powell, Ohio, USA
1966 230SL, Euro, Auto, Leather, both  tops
1994 E420

[n/a]

When I bought my car the transmission made noises and when I changed the fluid it was filled with metal chips.  After taking it apart I found that the bearing between the input shaft and the output shaft had disintigrated.  This explained why the tranny was noisy in all gears exept 4th.  In 4th the two shafts rotate at the same rpm.  

This was about 9 years ago and the price for new shafts was ridiculous.  I guess now it would be ludricous.  I bought a used tranny and put it in.  I am curious if there are numbers on the transmission that are matched to the VIN.  DOes anyone know?

[Tom]

Kevin,

Yes, the transmission number is a part of the matching numbers of the car.  The transmission number is on the data card and on a metal plaque on the transmission.  If you switch out the transmission, the numbers will no longer match.  For some, this does not matter.  But I think matching numbers will generally bring a higher price at resale.

Best,

Tom


1971 280sl Tunis Beige Metallic (restored & enhanced)
1971 280sl Tobacco Brown (low mileage stock)
1970 280sl Deep Red (Project Car)

[waqas]

Anyone know if the axles are interchangable between the 113 and others of the same era? (108, 109, etc) i.e, will I need the entire rear assembly (diff/axles/struts/comp-spring, etc) as a complete unit from the donor vehicle?  Also, any propeller shaft modification needed? (length etc)

waqas
--
1965 230 SL Euro, 4sp. manual

[ja17]

Hello Waqas,
Yes sedans of the era had rear axle assemblies which will directly interchange. The W111, W108, & W110, sedans coupes and convertibles will change over easily. Do not use a W109 or W112 chasis air suspesion rear assembly they will not change over. The earliest sedans had drum brakes also. Most had rear disc brakes. The W113 compensator spring different from the sedan spring. The W113 spring will change over replacing the sedan spring or compensator. Driveshaft hook-up is the same. Use your W113 springs also.

Removal of the exhaust is normally chosen to make access better during the process. Ratios 4.08, 3.96, 3.75, 3.69 and 3.27 were some common ratios.

Joe Alexander
Blacklick, Ohio

[waqas]

My rear axle/differential assembly is enroute-- I managed to find an original 230sl axle with 3.75 differential ratio. In the mean time, I've started removing bits and pieces. This evening, as I removed the exhaust/header bolts, I realized that maneuvering the exhaust pipes out from under the car may not be as easy with jack-stands under only the rear half. How high do you think I need to raise the car before I can maneuver the entire exhaust out from underneath?   Also, I usually support the rear on the trailing arm mounts to the chassis. Since I need to remove the trailing arms for axle removal, is there any other relatively safe spot to place jackstands under the rear?

waqas
--
1965 230 SL Euro, 4sp. manual

[ja17]

Hello Waqas,
Try raising the car just on the right side to remove the exhaust!

After exhaust removal, jack up the car on all corners. You will need to block up the vehicle in the rear and leave access to the rear suspension for removal. Do not allow the right rear axle to hinge down hard against it's casting which can crack! Prevent this by removing the transverse compensator spring first.

Check your new unit by unclamping the larger boot clamp and inspecting the thin lip of the casting for cracks.


Yes you should closely inspect the axel boot. Replace it if at all questionalble.
Also if you split the axle to replace the axel boot you will have performed the work required to repair your original broken rear axle. Maybe you should practice on your original first to see what is involved. You can change the broken yoke assembly and have a spare rear axle assembly while your in there!




Joe Alexander
Blacklick, Ohio

[Benz Dr.]

Just did this job on a 220Sb sedan.  The replacement axel was cracked and a piece was broken out. I already had this axel ready to go in so we had to take it apart. Ricardo was here at the time and somehow I put it all back together yet managed to install the shaft backwards. We had to take it all apart and start over.
 The old one was so loud due to gear play that you couldn't have a normal converstation without shouting and all the windows were rolled up. It also had next to no brakes because the rear cylinders were leaking. This axel is a carbon copy of the 230SL.
 Oddly, it's a 4.08 ratio out of a 200 fin car. Excellent condidtion without any real wear.

Dan Caron's
 SL Barn
benzbarn@ebtech.net
 slbarn.mbz.org

[waqas]

Alright. I was able to remove the exhaust and rotate it to the right, without removing it entirely from the car. quite amusing actually. It seems my exhaust seals either disintegrated, or were never installed in the first place (at the exhaust manifold header). In any case, I shall install new ones. I disconnected the e-brake cables and brake hoses. I surveyed the damage, and it looks as if some seal exploded in there! From what I understand, here are the recommended steps in order (even though they somewhat differ from the Haynes and BBB instructions):
(1) remove springs first
(2) remove shocks (supporting axles from thereon)
(3) then remove compensating spring (according to ja17's instructions)
Sunday is national car repair day in Austin, Texas, and I shall attempt the above if no objections are raised.

Waqas

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[ja17]

Hello waqas,
 
I leave the rear shocks attached until until the right axle half is supported with a floor hjack or such. This will prevent the axle from hinging down hard against it's casting.  Let the rear axles hang down releaving pressure on the compensator spring. Remove the rear compensator spring next. Removal of the compensator spring should be done with a spring compressor (compressed springs are very dangerous).

You can support the axle halves easily with a floor jack and disconnect the trailing arms and remove the rear springs (no spring compressor needed for these).




Joe Alexander
Blacklick, Ohio

[waqas]

I was able to remove the springs and shocks yesterday (rear axles are supported). Having lowered the axles quite bit, I was still unable to get my spring compressor jaws into the compensating spring. I'm now considering making my own tool... but does anyone have a recommendation on a commercially available spring compressor that will fit?

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Download Attachment: axle_support.jpg
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waqas
--
1965 230 SL Euro, 4sp. manual

[waqas]

My new (to me at least) differential arrived this afternoon, and I just completed a photoshoot: I have a ton of questions (please bear with a newby like me).
Download Attachment: new_diff.jpg
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(1) First of all, my axle boot looks ok. Is there any conventional wisdom out there regarding replacement? It seems like a lot of work to replace.
Download Attachment: axle_boot.jpg
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(2) The differential hanger/mount is a big unknown to me. Any suggestions?
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Download Attachment: diff_hanger2.jpg
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(3) It seems that the e-brake cables and attachment points are still intact. How can I check to make sure they are usable and safe? (and thereby obviating the need to remove and replace them from the drum assembly)

(4) What in the world is this little pipe sticking up in the air? It has a little cap on top, which seems somewhat loosely attached. Anything to worry about?
Download Attachment: diff_pipe.jpg
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(5) Lastly, how can I tell if my differential is of the correct ratio? It has the following part number stamped on the case (driver's side):  110-357-0018  (I don't see any other numbers)

Thanks for any assistance.

Waqas in Austin, Texas

[rwmastel]

quote:(4) What in the world is this little pipe sticking up in the air? It has a little cap on top, which seems somewhat loosely attached. Anything to worry about?

Breather tube to release pressure build up (from heat?) in the differential.  It must be kept clean.  Rumor is that if this is plugged then fluid will come out the pinion seal.

quote:(5) Lastly, how can I tell if my differential is of the correct ratio? It has the following part number stamped on the case (driver's side):  110-357-0018  (I don't see any other numbers)

On the lower part of the rear of the differential there should be a small (2 inches) half-circle that is flat and has the ratio stamped into it.  It will say 3/75 or 4/08 or something like that.

Rodd
Powell, Ohio, USA
1966 230SL, Euro, Auto, Leather, both  tops
1994 E420

[A Dalton]

The rear hanger is easy to check when the rear diff is out by checking the lateral play grabbing the hanger arm at top and rocking foward/backward..
 These are often over-looked  [ vs the often changed top support one in the trunk mount]..
 .if the front seal shows evidence of long time leak/seeage, then the rubber in the support is shot.
 The other reason to check these is cuz the first ones were a two piece rubber inset.  They were later changed/modified to a single, much better full length support. The ratio on yours may be found on a machined flat just in front of the lower/front, outer/left axle
tube mounting bolt.  The first series of #'s will be the serial and the last 3 will be the ratio.. they will use a comma on the ratio #, vs a colon as commonly used here in the USA.
 ie ... 3,75 rather than 3:75

[jlennon3]

If you've still got the "new" rear end out, you'll be way ahead of the game by doing some extra work now. Well actually a lot of extra work, but very satisfying work. You really should replace the rubber "boot", unless you know it's been replced prior. While you're at it you'll want to replace the axle shaft seals (since you have to remove the axles to replace the boot). There's a trick to pulling the axle shafts; not difficult but essential to ensure you don't break a snap ring (can't remember the details, but they're in the BBB). Also check the axle bearing and replace if necessary. Also replace the rubber seals and, if necessary, brass bearings at the axle pivot point. I didn't do anything with my pinion seal; didn't feel comfortable trying to set "pre-load" by myself (there's probably not many mechanics left that know how to do it). It's a couple days work, but you'll feel a lot better knowing you won't have leaks, bearing failure, etc and have to go to all the trouble of removing your "new" rear end after you've gone to all the trouble of installing it.....

[graphic66]

As for the compensating spring, if you havn't yet take out the fuel tank, it will be worth the extra work. I had to take a spring compressor and grind the ends until they fit into the spring. I could only get one compressor on it. Be carefull it's a real loaded gun waiting to go off.

[waqas]

I finally found the semi-circular machined surface with the ratio stamped "SL 3/75". Armed with the knowledge of where to look.. I found that my existing differential shows "B 4/10".. confirming that it was not original (and promising a noticable improvement when I'm done). My previous clue was the fact that my drums had studs instead of threaded sockets for the lug bolts. Another interesting note: the welded seams on each end of both axles are quite noticable! I saw them on my "new" rear end, and panicked... but then I found similar seams on my old axles at the same spots... was this standard MB practice? they seem awfully unfinished compared to all the fine joints and seams everywhere else...

I appreciate all your input... it appears that I shall have to break my vow of finishing this job before May 1st, and do it right. Feel free to continue providing guidance.

Waqas in Austin, Texas

[Benz Dr.]

You don't have to pull the axel if you use a split boot. If you split the axel in two you will find out just how much work that is and how tricky it is to do it. The slip coupling also has to be removed before you can take the hinged side off.
You can install the split boot without removing anything although is easier to do this with the cpmpensating spring removed.

We found a way to remove and install the spring that's really quite easy, but as in all things involving springs, you must be very carefull and have good tools to work with.
What we did was to install the right flange that holds the spring using only one screw. We left the outer one out and used a long piece of wood placed under a heavy floor jack with the other end under the flange. I locked the wheels of the jack in place but if you lift straight up it will be safer. As you raise the jack upwards the spring will compress and when it moves just far enough you carefully install the second screw. Install time is about 5 minutes.

You can remove the spring the same way by always taking the outer screw out first. This allows the flange to swing down out of the way with the jack placed under it. Always have the axels fully down to release as much tension as possible from the compensating spring.

This isn't advice for people without a hoist or a good floor jack. You need to understand how things can move and how to line things up. This is also a 2 man operation. Trying this by yourself could get you hurt.

We are able do this operation here, but then we often do things that can't be done ~)

Dan Caron's
 SL Barn
benzbarn@ebtech.net
 slbarn.mbz.org