I came across an 040/black tex' 91' 350SD which I am looking to purchase but the car needs a transmission. The owner states that the car has reverse and 1st and will creep on level ground but as soon as you give it some welly.. (gas) the transmission slips badly and the engine just revs..

My question is, Could I use a rebuilt 84' 300SD transmission as a replacement? Being the ratios are in the rear, will the 300SD's handle the added torque of the 350? The 350's transmission is hard to locate. Eventually I want to do some power adders to the 350SD but that will come in time..

cheers,
Chris

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No. It won't bolt up, different bellhousing.

The Tranny issue MAY be a Red Herring.

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If it has a rebuilt motor just have the trans rebuilt.

-J

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1991 350SDL. 230,000 miles (new motor @ 150,000). Blown head gasket

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Compu - a couple of months ago I looked into having my 81 300SD tranny rebuilt. They wanted $4200!!! here in Atlanta. So are you thinking his 350 transmission can be rebuilt for something reasonable? Which $4200 is not.

it could be a simple B2 piston replacement needed on the transmission...

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Thanks guys, I was going to pull the transmission out of my 84' 300SD which it along with the 617 which was rebuilt for an absurd amount at a local stealership in NJ. I then modded the 617 with M-pump, injectors, turbo, IC etc.. The P/O I snagged the 300 from loved the car although she was rusting (typical rear glass metal and D/S rocker floor). To clarify, The 350SD will drive brilliant in reverse, and when on level ground, will creep in drive.. any touch of the gas pad and it will just slip as if it were in neutral; but when the idle settles it will creep again forward.. It's a shame to let this one go as it is phenominal condition sans the transmission. He had the head and gasket done 10K previous to this condition. Would any other transmission retrofit into the 91'? I would like to remove her transmission and rebuild it as a spare..

OR...

I can swap out the 350's drive and install the modded 300's... how's that sound so far??


Cheers,
Chris

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First of all, you don't have an 84' SD, that means 84 feet. Drives me nuts, it's '84 (apostrphe goes where you removed letters/numbers).

Moving on, the '86/'87 SDL should have a similar transmission, with a couple of important differences:

The '86/'87 SDL engine revs to 5150RPM, the '90/'91 SDL engine only to 4650RPM. The early engine also makes its power up higher.

What that will mean is most likely your car has a lower-stall torque converter, which you can easily keep on your car after a flush, but also much earlier shift-points.

Whether the early transmission can be adjusted to shift lower just with the Bowden cable adjustment I don't know, and the downshift solenoid will also try to spoil the party, meaning that the engine might rev-limit before shifting at full-throttle.

You could also keep your valve-body to keep your shift points, but that is an additional risk as it could be the problem, and additional work at which point you're pretty much better off repairing your transmission? I don't know.

Best of luck either way, the '90/'91 SD/SDL transmission is not going to be easy to find.

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- Jeff

[QUOTE=babymog;2694036]First of all, you don't have an 84' SD, that means 84 feet. Drives me nuts, it's '84 (apostrphe goes where you removed letters/numbers).


sometimes my '84 feels like it's 84 feet.. LOL... But on the serious note.. I have spoken to another member and he stated that the '84's drive train will be powerful enough to run the 350SD's body. They are both the same length but my question is, are there anyother electrics that I have to keep an eye out for to operate the 300's drivetrain into 350?

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AC is the only issue. Pretty different on the two. Maybe a custom bracket for the later style to fit on a 617.

There's almost no electrics on the drivetrain, they can be ditched/replaced easily (ELR, various temp sensors).

Also the 350 driveshaft is bigger than the 617 transmission output flange. I suppose you can swap output flanges, assuming you don't run into driveshaft length issues (since the L is longer than an SD I don't think you can just grab an SD driveshaft).

The differential ratio is different too, presumably because of the more powerful engine they chose a steeper ratio.

Not sure really.

Someone here was doing it, but I don't know if he ever finished.

You will lose HP and torque, lose fuel mileage, gain noise and smoke, and lose value.

The starter wire will move to the other side, alternator IDK, fuel lines should be easy to modify, glowplug relay from a 300D 2.5T should work, radiator and hoses from donor car, not sure on drive shaft as the donor is a shorter car and the engine /trans is a different overall length, tachometer, A/C, PS, other items I really can't say as I'm not a 617 guy.

Seems like the better answer would be to find or rebuild a transmission, much less work and I'll bet that this swap will end up costing much more than expected. Otherwise, sell the SDL and buy an SD if that's what you really want, I might know a buyer.

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Both of them are SD's and the length is identical, well my 300SD has euro bumpers and lights which I am going to transplant into the 350SD. I may try some things to see what will fit. Being a Gen 2 W126 the body is close to flawless as is the interior and the engine condition. The transmission actually shudders when given gas to accelerate. Fluid is red and doesn't smell burnt. She runs in reverse normally with no whine or vibration. As the owner does state, I shifted her into drive and she does creep forward in the driveway but when the gas is pressed she shudders and slips..

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"Why operate within the law when you can operate above it?"

MB roster
'85 500SE euro Ratrod
'92 500E's x2 / '94 E500 stored
'91 560SEC w/43K stored
'92 Cabby 16V OE 2.1 AutoX car
JDM RHD cars now.

Sounds slightly easier. Can you live without AC for a while? Since that's the only part that's not plug and play.

Fluid level?

Then it seems that the driveshaft from the donor should work, although the yoke might be the 90mm and you might need to use the front from one, rear from the other, and have it balanced.

Still seems like a waste of a nice '91 to put a cement-mixer under the hood, to each his own.

Do a search on 617 into SDL or similar, the thread is here somewhere and I believe the guy had both cars, someone else might remember what the thread was titled.

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Gone to the dark side

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maybe this one
http://www.peachparts.com/shopforum/showthread.php?t=221164&highlight=617+SDL