This weekend I am swapping out the transmission in my 1980 W116 300SD (722.120 transmission). The internal seals are shrunken and aged which does not allow the transmission to function until the car has been running for some time, and even then it slips. The transmission also leaks badly and the car has about 400,000 miles.

I have a spare transmission from a 1979 W116 300SD (also a 722.120) that was rebuilt locally 100,000 miles ago in 1991 at Mercedes Auto Service (cost was $2,021.25). The problem with this one is that the flex plate broke and the fragments shredded the inside of the bellhousing, broke off some of the bellhousing vents, and scratched up the torque converter.

I am confident that metal particles did not get inside the transmission as the input seal was doing its job. I am hoping this is true. I plan on using the bellhousing from my old transmission on the replacement. I purchased a new bellhousing gasket (and input and front pump seal).

When I install my old bellhousing on the replacement transmission, should I use sealant on the front housing gasket, or install it dry? Does anyone know what the torque specs for the bolts that attach the bellhousing to the transmission body is?

I'm going to replace the input shaft seal and front pump seal while the transmission is out. I think the rest of the seals will still be good, but if not, I should be able to change them later with the transmission in the car. I've got all of the new shift bushings and a filter kit as well. I plan on reusing the original torque converter. I'll try to check the flex plate for cracks.

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DON'T MESS WITH MY MERCEDES!


1967 W110 Universal Wagon, Euro, Turbo Diesel, Tail Fins, 4 Speed Manual Column Shift, A/C
1980 W116 300SD Turbo Diesel, DB479 Walnut Brown, Sunroof, Highly Optioned, 350,000+ Miles

The specified torque for the hex head bolts for the front transmission case is 1.3 mkp => that's 12.7 Nm (conversion:- multiply by 9.81)

Good luck with the project - post some pictures

I'm in the middle of redoing my 722.118 so if you get stuck with something I might be able to help.

I've found this exploded view to be quite useful for pulling stuff apart - more concise than the ATSG manual!

http://www.ganzeboom.net/images1/ganzeboom/parts/Mercedes/722.0,%20722.1,%20722.2.pdf

Edit:-

I forgot to say I'm not planning on using any sealant just clean and dry undamaged mating surfaces for me please.

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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!

Thanks for that information! Someone on another forum said he didn't use sealant, either, and no leaks so far.

__________________
Stop paying for animal enslavement, cruelty, and slaughter. Save your health and the planet. Go vegan! I did 18 years ago. https://challenge22.com/

DON'T MESS WITH MY MERCEDES!


1967 W110 Universal Wagon, Euro, Turbo Diesel, Tail Fins, 4 Speed Manual Column Shift, A/C
1980 W116 300SD Turbo Diesel, DB479 Walnut Brown, Sunroof, Highly Optioned, 350,000+ Miles

Another forum? Is there any other?

__________________
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!

I agree- can't see any reason to use sealant at that joint. I didn't when I fixed my 722.120 front pump.

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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 (??)

http://www.w116.org/

__________________
Stop paying for animal enslavement, cruelty, and slaughter. Save your health and the planet. Go vegan! I did 18 years ago. https://challenge22.com/

DON'T MESS WITH MY MERCEDES!


1967 W110 Universal Wagon, Euro, Turbo Diesel, Tail Fins, 4 Speed Manual Column Shift, A/C
1980 W116 300SD Turbo Diesel, DB479 Walnut Brown, Sunroof, Highly Optioned, 350,000+ Miles

Scroll down this thread for details on how the transmission replacement went: My Custom 1980 W116 300SD Project

__________________
Stop paying for animal enslavement, cruelty, and slaughter. Save your health and the planet. Go vegan! I did 18 years ago. https://challenge22.com/

DON'T MESS WITH MY MERCEDES!


1967 W110 Universal Wagon, Euro, Turbo Diesel, Tail Fins, 4 Speed Manual Column Shift, A/C
1980 W116 300SD Turbo Diesel, DB479 Walnut Brown, Sunroof, Highly Optioned, 350,000+ Miles

That was a lot of work eh?

Looks good now though - all nice and clean

__________________
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!