My transmission was operating and shifting fine prior to this morning when it would not engage any gears (either forward or reverse). Tranny oil level is good. The oil smells and looks normal. This car has 185,000 miles on it. I checked the bushing and shifter . It appears to be functioning properly. I made sure that the linkage at the transmission was moving as the shifter was moving. I dropped the oil pan. The oil is a bit darker than new colour and clear no debris suspened it it. No burning oder. The pan itself is clean--no metal particles or anything in the bottom of the pan.
What else should I be checking while I have the pan off?
Any ideas whats causing this problem? Thx

Sounds like something disconnected or broke - such sudden failure is odd

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Current Diesels:
1981 240D (73K)
1982 300CD (169k)
1985 190D (169k)
1991 350SD (113k)
1991 350SD (206k)
1991 300D (228k)
1993 300SD (291k)
1993 300D 2.5T (338k)
1996 Dodge Ram CTD (442k)
1996 Dodge Ram CTD (265k)

Past Diesels:
1983 300D (228K)
1985 300D (233K)

Thx for the response. I kinda puzzled by this issue myself. Could a faulty b2 piston cause this?

Having just gone through replacing the transmission in my SD my symptoms were different, but I did a lot of reading on these forums. Your problem sounds like it may be a B2 piston failure. I wish my repair was as concise as yours.

If I remember correctly a sudden and unexplained inability to get into gear is a B2 symptom.


You've got a bit of work ahead of you in a w123 but the costs are not too great if you do the work yourself.

One time I forgot to connect a shift rod to the valve body after a valve body repair and was stuck in first gear. Puzzled the heck out of me until I pulled the pan.

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This area is typically used to brag about one's current or former automobiles.

Yes. But take it out and check it to make sure before you go out and buy one, save a hundred bucks.

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TC
Current stable:
- 2004 Mazda RALLYWANKEL
- 2007 Saturn sky redline
- 2004 Explorer...under surgery.

Past: 135i, GTI, 300E, 300SD, 300SD, Stealth

Any pressure in the cooler lines? Could be a torque converter issue as someone else was talking about. It is not turning the pump.

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83 300SD Dark Silver Dark brown inside

I read that the b2 piston only activates forward gears and not reverse! I'm thinking it may be the torque converter or the pump(pump drive gear) . I have been quoted $1500 to rebuild this transmission! Do you what other car mercedes 300 series car use the same tranny?

where are you located. Maybe someone close knows of one.
Any SD or D trans may work. Make sure that the switch on the side is the same. My 85 sd was differant and was not just able to move the switch.

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83 300SD Dark Silver Dark brown inside

I'm located in Toronto, Canada.
I'm looking for a tranny that will just plug and play without any or very little retrofitting. What models / years should I be looking for? Thx

Missed the part about not engaging reverse - post above is right, this wouldn't be the B2. Sounds like OP has a lot of work cut out.

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TC
Current stable:
- 2004 Mazda RALLYWANKEL
- 2007 Saturn sky redline
- 2004 Explorer...under surgery.

Past: 135i, GTI, 300E, 300SD, 300SD, Stealth

Could be the TC or front pump. Though seemingly more robust on the 722.3xx than the 722.1xx, one of the 3 "parts " trannies I have has a sheared front pump. If that's all it is, its a fairly easy fix. Pull the transmission line at the radiator and see if you have any working pressure.

Rick

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80 300SD (129k mi) 82 240D stick (193k mi)77 240D auto - stick to be (153k mi) 85 380SL (145k mi) 89 BMW 535i 82 Diesel Rabbit Pickup (374k mi) 91 Jetta IDI Diesel (155k mi) 81 VW Rabbit Convertible Diesel 70 Triumph Spitfire Mk III (63kmi)66 Triumph TR4a IRS (90k mi)67 Ford F-100 (??)

I already removed the fluid. Can the pump or the TC be repaired without droping the tranny?

Nope- it's gotta come out, but you don't have to get involved with all the black magic that goes on inside a slushbox.

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80 300SD (129k mi) 82 240D stick (193k mi)77 240D auto - stick to be (153k mi) 85 380SL (145k mi) 89 BMW 535i 82 Diesel Rabbit Pickup (374k mi) 91 Jetta IDI Diesel (155k mi) 81 VW Rabbit Convertible Diesel 70 Triumph Spitfire Mk III (63kmi)66 Triumph TR4a IRS (90k mi)67 Ford F-100 (??)

What do mean by "you don't have to get involved with all the black magic that goes on inside a slushbox"? While I have the tranny out wouldn't it make sense to replace the clutches/bands etc? This tranny has 187,000 miles on it.

If you wish to fix only the specific problem, you don't need to go heavily into the box.

But, a box with 187K is really near the end of it's useful life and, if you're keeping the vehicle for awhile, a rebuilt should be a consideration.