Hello Gentlemen,

Can someone confirm that a 2:47 rear diff from a W126 that mounts to this kind of differential mount:

http://catalog.peachparts.com/ShopByVehicle.epc?q=1984-Mercedes--Benz-300d-Transmission&yearid=1984%40%401984&makeid=63%40%40MERCEDES+BENZ%40%40X&modelid=6192%3AMBC%7C1504%3AED%7C10000135%40%40300D&catid=241185%40%40Transmission&subcatid=241372@@Differential+Mount&mode=PA

will bolt right in, without any modifications to a W123 that has a 2:88 stock rear diff?

I have just been dreaming for a while now of cruising along the freeway @ 70MPH @ < 3000 RPM....

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'85 300D Turbo - CA Version

If it is an early 126 it will bolt in with minor modifications, I believe.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

as long as it comes from a pre 86 126 you should be fine.

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

What are the minor modifications involved? Is it going to involve the swapping of their input shafts/pinions? Because I did some research around and found out that 1983 SEC and 1984 D have different part numbers on flex disc/joint....

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'85 300D Turbo - CA Version

Yea that's what I thought too, but I just wanted y'all's expert advice and opinions to make sure. The 2:47 diff is coming off from a 1983 380 SEC and based on their part numbers, the SEC's and the D's have the same rear diff mounts but different flex discs/joints, but the same rear wheel hubs, but I'm not sure about their axle half shafts....

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'85 300D Turbo - CA Version

You will have to remove your existing pinion flange (or get another flange if you don't want to disturb your 2.88) and install it on the 2.47.

Before touching it, you need to measure the pre-load with an inch pound torque wrench on the pinion flange (not the torque on the nut), in order to properly install the new flange. Once you get that figure, then you tight the nut until you get the same reading.

A similar procedure is shown starting at 2:00 (two minutes) into this video of a guy setting a Ford diff.

http://www.youtube.com/watch?v=8APYO2sZyJU


Over tightening the nut will result in the bearing to burn up or cause a whining situation.






.

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1983 123.133 California
- GreaseCar Veg System

Thanks for the tip DeliveryValve! I sure will do it.....

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'85 300D Turbo - CA Version

Is this type of Torque Angle Gauge work with properly setting the pinion flange nut?

http://cgi.ebay.com/1-2-Torque-Angle-Gauge-Rotation-Angle-Meter-Measure_W0QQitemZ280482428424QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item414e0e3608

I've never used one of these and I don't even have a clue how it really works?? I guess if it's gonna work, I'll just figure it out....

Thanks!

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'85 300D Turbo - CA Version

No that is an angle of rotation tool used for TTY (torque to yield) bolts found in the cylinder head, flywheel, con rods, and etc.

What you need is a inch pound torque wrench, preferably a beam or dial type, but not a clicker.




Hope this helps.

.

Attached Thumbnails

   

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1983 123.133 California
- GreaseCar Veg System

Ahh...I see.... Thanks for correcting me! You think a 0 - 12.5 in-lbs would suffice or I'm gonna need at least the 0 - 60 in-lbs?


....and by the way, I finally pulled the rear diff from the bone yard this afternoon and the inner can of the CV axle half shaft has metal ring hugging the can that splits at half, like 2 letter C's and are bolted together by 2 6mm allenhead bolts, my question is what are those for? a counter weight/balancer? or some kind of a sensor thingy?

...and can I use that same CV axle half shaft from a W126 to my W123?

...by the way the W126 CV axle is a homokinetic type, which doesn't have the annular flange with bolts.

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'85 300D Turbo - CA Version

The Homokenetic and the Annular axles will both fit. they both fit in the hub and Diff the sameway. with the Homo`s the Diff has to be opened up to pull the "C" clip.

From what I have read here on the Forum, the 126 axles and 123 won`t interchange. think the 126 are a hair longer.

There was a thread about a yr back "setting the preload" or something like that. where "Arther Dalton" got me to understand the preload on the pinion bearing. very important as "Deliveryvalve" said.
If I was home, I would post it here. do a search on my name.

here is another angle of the torque wrench to use. It shows the torque value both ways on the dial. very improtant to see how much it takes to turn the flange, or shaft before taking the nut off. then it has to be put back the same amount of torque.
It is the amount it takes to turn the shaft, not how tight the nut is.

http://cgi.ebay.com/SNAP-ON-1-4-DIAL-TORQUE-WRENCH-0-75-LBS-P-N-TE6FUA_W0QQitemZ390173593276QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item5ad8288ebc



Charlie

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there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works

Thanks for the info Charlie!

The reason I'm asking if I can use the W126 axles that are currently installed on the 2.47 diff on my W123, is I'm just trying to get away with the opening of the differential, because it seems to be all intact and leak free and the rubber boots on these W126 axles were in good shape, the axles on my W123 right now are the chinese replacement GSF from AdvanceAutoParts, but since you mentioned that they're not interchangable, I guess I have no choice... but to re-use my GSF axles....

...about the setting of the pre-load, does the differential has to be turned while setting it without any loads or should I say while no CV axles are installed?

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'85 300D Turbo - CA Version

Which ever way you checked the preload, whether mounted under the vehicle, or on the bench. Tighten it back down the same way.

still mounted to the vehicle, would take more to turn it with the axles installed.
Mounted to the vehicle with the axles removed, would take less to turn it. less resistance or friction of moving parts.

Charlie

Finally back home. here is that thread of determining the friction preload.

Pinion Seal Replacement - How to determine Friction Load

__________________
there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works

Thanks for the link, Charlie! You've always been very helpful! I read through all the post on the thread link that you attached and it's very helpful except I have one question that I need you to clarify to me, if you don't mind....

It's about the other member's post from the thred link that you attached about "Official Mercedes Manual" on posts #'s 23 and #26 that the torque of the pinion nut is 180 N-m?

But based on my understanding of what you were telling me:
1) before I remove the nut, I have to determine the pre-load torque of the flange using an in-lb dial torque wrench
2) remove the nut
3) swap the pinion flange
4) turn/tighten the nut a little at a time, while reading the pre-load with a dial torque wrench, until I get the same reading on the dial that I got in step #1).

So, following all this steps, as long as I have the before and after pre-load value matched, it doesn't really matter how much torque a have on the pinion nut, correct? Even if it's < or > 180 N-m?

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'85 300D Turbo - CA Version

That`s correct. I think you got it. I had to reread the thread again my self. dragged out my FSM and read the section on the preload etc...

Go back and reread post# 13 & 15 in that preload thread.

Once the light comes on, it gets clear how to set it up, and understand the 2 torque values. tightening the nut and turning the gears.

I still haven`t swapped the flanges on the 2:47 Diff like I was going to do, and install in the 85. the 2:88 Diff in their now, and with the 4-speed manual, I think it might be a little too high geared to go higher. now if I had a transmission with a couple more gears to split between a couple of them, it would be better.

Charlie

__________________
there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works