I have a 1986 300 SDL and I would like to know if any other transmission is able to be swapped (from other models and years) as a replacement? If not does anyone have a used one for cheap?

Thanks for reading...

Ron
Richmond, Virginia

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I expect an '87 300SDL has the same transmission. The 90-91 350SD/L transmission will be very close.

Depending on what's wrong with your transmission, the transmission from an '87 300D/TD can be made to work (different speedo drive) but for most the effort isn't worth the cost savings.

Have you exhausted simple fixes and what can be addressed without removing the transmission?

Have you checked the parts forum for what's available?

Sixto
87 300D

The problem I am having is once the transmission warms-up, it starts to not want to shift from 2nd - 3rd, or 3rd - 4th. These is also some flaring when it is changing gears. The speedo also does not work at all. I have checked and replaced the fuses for the speedo.

Things that I have done:

1. Changed the fluid and filter.
2. Added transmission additives to the fluid.
3. Checked the Bowden cable.
4. Checked the linkage.
5. The fluid when changed smelled old and not really burnt.
6. When draining the transmission to add the additive, the fluid smelled the same.
7. Checked and disconnected the kick-down switch.

I have ready about cleaning the filter screen about the valve body. But I have not completed this task. Still a little nervous about messing something up.

The car does have 280,000 miles and the transmission was replaced two years ago by the previous owner. I can tell the some of the routine car for the car was neglected. The person I purchased it from was the original owner and elderly.

I am hopefully that I can find an option that will not require removal of the transmission.

Thanks

Ron

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If I had to guess, and I have a terrible average, I'd say a piston or seal leaks as the fluid warms. Do a search on the Superior shift kit and B1 and B2 piston. Try the tech forum as well since the tranny issues have nothing to do with what fuels the engine.

Sixto
87 300D

Do these kits require removal?

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The shift kit requires removal of the valve body but not the transmission. I think both the B1 and B2 pistons can be serviced without separating the transmission from the engine but it helps a lot, and maybe the only way to go, is to drop the exhaust system and prop shaft to be able to lower the tail end of the transmission and angle it for working room.

Sixto
87 300D

Ron

This is exactly what happened to my transmission. Replacing the B2 piston fixed it. Please do not replace transmission ($$$ costly) just the B2 piston.
Good luck

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1987 300SDL 314K mi, counting; #22 Head
1999 E300Turbo 405K original miles
1997 E320 180K mi (Son's)
2002 ML320 (Son's)
1998 S320 140K mi (Son's) sold
1985 300SD 311K mi
1984 300D 324K mi (killed by a hit-n-run turd)
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WOW, very interesting and thanks for the info. Were you able to do the B2 replacement yourself? Did you remove the unit or replaced it on the car?
Thanks to both you and Sixto for this help. i was seriously dreading replacing the entire unit.

Ron

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Hey DeiselGuy53 / Sixto

When you replaced the B2 Piston, did you also replace the reaction valve at the bottom of the cylinder? Did you not need to replace the B! Piston? I am considering having the job done this weekend. Was it difficult?

Ron

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I had the transmission replaced in my 1986 Mercedes 300 SDL ( mileage is 280,000)and afterwards I was told the donor transmission was from an 1987 300 TD Mercedes. The one issue I've noticed is a very slow take off. It seems that the turbo is engaging. Is there a difference is the gear ratio or something. The original unit worked great minus the shifting issues. Is the sometjing I can do short of removal?

Also my speedo isn't working. It wasn't working previously and it doesn't work when I trade out a donor clyster.

Thanks

Ron

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Good question. I don't know if the 86-87 SDL has a 4.25 ratio first gear like 87 D/TD. If it's not 4.25, it'll be a longer 3.87 or 3.90. A key difference is the SDL has an inductive speedo drive while the D/TD has a mechanical drive. It's possible that the case used in the replacement transmission is has a D/TD 722.317 part number but has a tail housing from a 722.321. Otherwise you couldn't hook up the speedo cable. Well, you can't plug a mechanical drive cable into an inductive type tail housing. Maybe it hooks up the other way but it won't drive the speedo.

If it's slow to take off, check the basics like a clear signal path from the manifold to the ALDA, etc.

Sixto
MB-less

Can you explain what you mean b a clear signal path? I think whatever needed to be switched for the speedo, was switched out.

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I forgot to mention, that it seems like the transmission is shifting early too.

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There is a lot of info available on these transmission. Find the Mitchell site and ask Professor Google for the info ie: "Mercedes transmission 722 site:whatever the actual site is". A PDF with diagnostics and governor settings and other specs will pop up.

The trans model number is located on the passenger side above the pan gasket. You'll need they number to be sure what space to use. There are also pics on this site and youtube.

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85SD 240K & stopped counting painted, putting bac together. 84SD 180,000. sold to a neighbor and member here but I forget his handle. The 84 is much improved from when I had it. 85TD beginning to repair to DD status. Lots of stuff to do.

Signal path = boost pressure sensing. Confirm your even seeing boost to begin with. This would explain sluggishness, what it "seems" to do is useless, you need data. Grab a boost gauge and tubing, end of story.

Shifting early most likely result of interrupted/no vacuum. This is the always first issue to attack on our diesels and to get working correctly. Don't worry about or move on to other "problem" areas til you're certain vacuum system is copasetic.

No speedo could be number of reasons, but yours seems likely there is no pickup since you have a non-sdl transmission, one that did not use same ring gear sensor as sdl, so this is odds on fave. Easy to confirm, pickup sticking out of bell housing just aft of mating bolts at driver's foot level or "9o'clock" when in driver's seat (if that makes sense.) Seen threads where owner punched hole in bh to mount sensor and epoxied magnets to starter gear. Sound like something you're up for?

IS YOUR TACHOMETER OPERATIONAL??? For that matter is most everything rpm dependant working still? A/C, cruise, kickdown, etc.?

Your wonderful sdl has all the issues of yore wrt vacuum, but now you have the luxury of additional electrical failure points thrown in for madness' sake.

Still tracking down my file with all transmission ratios by model number. IIRC, sdl was slightly different from d/td, but definitely has a first gear start.

Have fun,

MBZ123

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1987 300SDL "Rhona" 218k
1986 300SDL "Johanna" 166k - Abducted 5/15 outta SFV Reward 4 info
1984 300TD "Petra" 212k - Parts yard pirate, arrrrgh
1982 300CD "FrankenFemme" 178k - Eyes only TS-XWRKS transplant abomination (loc. classified)
1980 230CE "Lulu" aka "Terminal" 277k - Dying the slow death
1985 300CD "Gerda" 203k - She ain't playin' SOLD
1983 300TD "Svetlana" 240k...and pleading for more. SOLD


"What a heavy load Einstein must've had...F&@%!NG morons everywhere!" - David Lynch