Hey all. I've been looking around on here and I can't find the exact info I'm looking for this time. I have a 1984 300td Wagon and the trans is leaking badly from what looks like the pump seal area..? amongst others. The car has almost 370k on it and instead of doing a reseal I've opted to swap in a rebuilt. My car has a 123.... 722.315 Trans. The mechanic I'm thinking of using has a rebuilt 126 ......722.317 (no idea what car this came from)...with the starter on the wrong side. He's gonna take that and put the internals into a 126....722.300 bellhousing (no idea what car this came from)with the starter on the correct side (passenger) and put that onto my car. Will that work? Will there be electric vs mech. speedo issues? any gear ratio issues? driveshaft issues? Is he missing something important here? Please advise. Thanks in advance MB Tranny Gurus!

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1984 Astral Grey 300TDT - The French Fry
1979 Yellow 300SD - The Pomme - SOLD
1985 Light Ivory 300DT - Fritz
1987 Anthracite Grey 300SDL - ?

With all that additional work he's planning....

I would ask him to just fix your original!--Prolly end up cheaper than his plans!

There shouldnt be any 'speedo and gear ratio' issues as all 722.3 have the same basic gearing, and the speedo drives are all the same.
There may however be issues relating to the valve-block/gear-change speeds relating to that. There could also be issues relating to the bowden-cable and the vac-modulator if this mongrel trans of his is based on some old gasser trans....

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http://i190.photobucket.com/albums/z...0TDnoplate.jpg

Alastair AKA H.C.II South Wales, U.K. based member

W123, 1985 300TD Wagon, 256K,
-Most recent M.B. purchase, Cost-a-plenty, Gulps BioDiesel extravagantly, and I love it like an old dog.

W114, 1975 280E Custard Yellow,
-Great above decks needs chassis welding--Really will do it this year....

I thought some later 126's had an electric speedometer?

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

Yes you are right--I think most of the W126 had elect type.

If its the mechanical type like on W123--then they are all the same though....

I went through all this when changing a 280TE gasser wagon into a 300TD diesel wagon...

They changed the speedo type in relation to the diff ratios, so I had to use the original 280TE speedo instead of a 300D speedo when I changed all the instrument cluster to the diesel type without a tach.....

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http://i190.photobucket.com/albums/z...0TDnoplate.jpg

Alastair AKA H.C.II South Wales, U.K. based member

W123, 1985 300TD Wagon, 256K,
-Most recent M.B. purchase, Cost-a-plenty, Gulps BioDiesel extravagantly, and I love it like an old dog.

W114, 1975 280E Custard Yellow,
-Great above decks needs chassis welding--Really will do it this year....

Yup, 126 and 140 applications have an inductive speedo drive. Also V8 124s IIRC. Don't know about 202s.

Another difference is some variants have second gear start.

I know cases can be repurposed because my 81 300SD came with a 722.315 case despite having all the 126 function and interfaces one could expect.

A 722.317 comes with the '87 300D/TD. The case, with starter bump on the port side, won't bolt to a 617 but it should have first gear start.

Sixto
87 300D

It's not that much more work to convert it to a manual transmission. Something to think about.

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Whoever said there's nothing more expensive than a cheap Mercedes never had a cheap Jaguar.

83 300D Turbo with manual conversion, early W126 vented front rotors and H4 headlights 400,xxx miles
08 Suzuki GSX-R600 M4 Slip-on 22,xxx miles
88 Jaguar XJS V12 94,xxx miles. Work in progress.

Ok, so the 317 has elec. speedo and I currently have 315 w/ mech. I don't want to mess with my instrument cluster, so is that a deal breaker or is there a workaround?

As for price, he's giving me a super deal....$1480 INSTALLED. He's closing his shop and has a couple rebuilt and used trannys he has to get rid of. He has even offered to rebuild mine for the same price given he has the parts and needs to use or sell them, more labor $$ ,and he still gets to sell the rebuilt to someone else.

I was hoping to get a working non leaking rebuilt into the car and have mine as a spare I could tinker with rebuilding or have it done by a pro at a later date. BUT..if there are gonna be some compatibility issues maybe rebuilding mine is the best bet. This is my daily driver and it needs to be AOK.

Sixto.. inductive means electric? Sorry if that seems daft.

Skippy, I'd have to have access to a manual trans asap then, and frankly, I prefer automatic for this car and the way I drive it. I want the car to do the work...not me.

I think I found a little more info... the 722.317 comes from 86 and 87 300d or td as listed by Sixto. The 722.300 (donor case) is from a 280 series gasser.

What would you guys do? The better deal for me obviously is to get the rebuilt put in (assuming no compatibility issues) and keep my trans. I get a spare that way. Is the better (safer) route to have him rebuild mine. Still a great deal I think.

Thanks guys.

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1984 Astral Grey 300TDT - The French Fry
1979 Yellow 300SD - The Pomme - SOLD
1985 Light Ivory 300DT - Fritz
1987 Anthracite Grey 300SDL - ?

You could simply not hook up the speedometer and use a GPS.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

If he's going to rebuild the transmission, he should be able to adapt the tail housing with the appropriate speedo drive for your car.

Inductive means the speedo cable has no pinion to be driven by the transmission. It's still a speedometer cable, it's just driven by magnetism rather than physical contact.

Sixto
87 300D

Ah. That sounds like good news to me Sixto.

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1984 Astral Grey 300TDT - The French Fry
1979 Yellow 300SD - The Pomme - SOLD
1985 Light Ivory 300DT - Fritz
1987 Anthracite Grey 300SDL - ?

Have a look for mach4's diesel in an SL conversion thread. There's a bit there about the tail cone sections on the 722.3 transmissions - the whole electronic / mechanical speedometer thing is discussed.

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1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

Well, Army....there was certainly alot of info there. Most of it over my head. The final outcome I believe is this. The mechanic did exactly what he said he was going to do with one exception....he took the speedo connection off of my original trans. I haven't seen it or gotten details if it was the tailcone in entirety or just the speedo connector ( I'm not sure exactly how that all works) I'll find out more tomorrow or the next day. The mechanic says he thinks I'll be pleased though. I'll let you know the final outcome.

Thanks so much everyone for the insight, suggestions and support. This forum rocks!!

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1984 Astral Grey 300TDT - The French Fry
1979 Yellow 300SD - The Pomme - SOLD
1985 Light Ivory 300DT - Fritz
1987 Anthracite Grey 300SDL - ?

It sounds like he's re-used the old tail cone section - but we'll have to wait and see - I'm intrigued!

__________________
1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

Ok... Sorry it took so long to post this update. He did use the entire tailcone section from my original trans. to address the speedo compatablity issue. After fixing two leaks... one from the B2 (i think) piston seal and one from the filler tube seal...all has been working fine. However, the new trans. exposed an issue that was for some reason not noticeably affecting my old trans. My Vacuum control valve was totally non operational. I took it apart cleaned and adjusted it. It's a completely different driving experience. I'm pleased for the most part, but I want to tweak the system a little more in order to get the shifts feeling just right for me. ( that may also involve a climate control vac overhaul, and while I'm at it maybe fix the door locks...But for now, no leaks and a decent shifting trans is OK by me. Now to re-boot the axles, replace rear shocks, rebuild sls valve and possibly pump, replace the thermostat, troubleshoot the aux fan, adjust the hood release cable, replace driver's door check, put driver's window back in the track, install a new hood pad, etc. etc. Whew! I'm exhausted already!! Thanks again for the support.

__________________
1984 Astral Grey 300TDT - The French Fry
1979 Yellow 300SD - The Pomme - SOLD
1985 Light Ivory 300DT - Fritz
1987 Anthracite Grey 300SDL - ?