Author Topic: Changing front seal on automatic transmission  (Read 1995 times)

CJHenderson

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Changing front seal on automatic transmission
« on: April 03, 2021, 14:21:12 »
Do I need to remove the bell housing from the transmission to change the shaft seal?
1970 280SL/8 W113 101624 miles.
1950 MG-TD
2021 Harley Davidson CVO Trike

Shvegel

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Re: Changing front seal on automatic transmission
« Reply #1 on: April 03, 2021, 20:35:34 »
No.  I changed mine 3 times before I realized it was the converter leaking at the rivets which is apparently common.  I ended up TIG welding the seam and around all the rivets before I got it to stop leaking.  I got pretty good at pulling the transmission out.

ja17

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Re: Changing front seal on automatic transmission
« Reply #2 on: April 04, 2021, 01:51:17 »
Yes, sorry to say that if you have a riveted converter, it should be pressure checked to see if it is leaking around the rivets. I submerged them in water and use shop air to check for leaks (bubbles). Also there is a large rubber o-ring around the front pump that you might want to replace if you have the transmission out. Unfortunately, the bell housing will need to come off to get the front pump out. :(  In this case, you will need the front bell housing gasket as well. Be especially careful that the two cogs on the converter engage the pump correctly before installation or you will ruin the front pump as you bolt the transmission to the engine. One way to be certain the converter stays engaged properly is to keep checking the converter to see if it turns freely during the bolt-up process. If it binds-up before complete bolt-up, then it is likely that the converter has dis-engaged the front pump during installation. If you continue to force the bolt-up process then the front pump will be ruined. A front transmission bell housing leak can be caused by any of these three problems (front seal, leaking converter, leaking front pump o-ring). Unfortunately the converter is often the culprit.
Joe Alexander
Blacklick, Ohio
1969 Dark Olive 280SL
2002 ML55 AMG (tow vehicle)
2002 SLK32 AMG (350 hp)
1982 300TD Wagon turbo 4spd.
1963 404 Mercedes Unimog (Swedish Army)
1989 flu419 Mercedes Unimog (US Army)
1998 E430
1974 450SLC Rally
1965 220SE Finback

CJHenderson

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Re: Changing front seal on automatic transmission
« Reply #3 on: April 04, 2021, 02:20:20 »
Thanks to you both. The converter isn't riveted so I think I'll go for the front seal only.
1970 280SL/8 W113 101624 miles.
1950 MG-TD
2021 Harley Davidson CVO Trike

mnahon

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Re: Changing front seal on automatic transmission
« Reply #4 on: April 04, 2021, 12:20:00 »
How do you know whether you have a riveted converter, without  taking the transmission apart? Is this based on the year of the car?
« Last Edit: April 04, 2021, 12:31:39 by mnahon »
Meyer Nahon
Montreal, Canada
1968 MB 280SL Auto Euro LHD Silver
2021 Tesla Model 3

Pawel66

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Re: Changing front seal on automatic transmission
« Reply #5 on: April 04, 2021, 14:51:01 »
I found out when it exploded.
Pawel

280SL 1970 automatic 180G Silver
W128 220SE
W121 190SL
G-class

ja17

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Re: Changing front seal on automatic transmission
« Reply #6 on: April 04, 2021, 15:36:51 »
Seems like only the later cars had the non-riveted converters.
Joe Alexander
Blacklick, Ohio
1969 Dark Olive 280SL
2002 ML55 AMG (tow vehicle)
2002 SLK32 AMG (350 hp)
1982 300TD Wagon turbo 4spd.
1963 404 Mercedes Unimog (Swedish Army)
1989 flu419 Mercedes Unimog (US Army)
1998 E430
1974 450SLC Rally
1965 220SE Finback

mnahon

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Re: Changing front seal on automatic transmission
« Reply #7 on: April 04, 2021, 17:33:24 »
Thanks Joe.

Pawel, was yours non-riveted?

Meyer Nahon
Montreal, Canada
1968 MB 280SL Auto Euro LHD Silver
2021 Tesla Model 3

Pawel66

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Re: Changing front seal on automatic transmission
« Reply #8 on: April 04, 2021, 17:50:56 »
The one that exploded was the ribbed one with rivets in the middle.
Pawel

280SL 1970 automatic 180G Silver
W128 220SE
W121 190SL
G-class

CJHenderson

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Re: Changing front seal on automatic transmission
« Reply #9 on: April 04, 2021, 20:44:41 »
My apologizes to the board, I do have six rivets. When I started to disassemble the car I didn't have any leaks from the transmission and when I stored the converter in a plastic bag and then boxed it I had never really looked at it. So I made the assumption that I didn't have a riveted one until today. Now I'm not sure whether to keep it or get another one since Pawel66 had that mishap.
1970 280SL/8 W113 101624 miles.
1950 MG-TD
2021 Harley Davidson CVO Trike

Pawel66

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Re: Changing front seal on automatic transmission
« Reply #10 on: April 04, 2021, 21:47:25 »
What I was told by the experts here at the time of that "mishap" was that it is best not to use the aluminum converter (clutch), but to use the new type, the steel one. The rivets, as I see described by Shvegel, can be taken care of. At the time of my event it was about the material.
Pawel

280SL 1970 automatic 180G Silver
W128 220SE
W121 190SL
G-class

ja17

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Re: Changing front seal on automatic transmission
« Reply #11 on: April 05, 2021, 07:30:04 »
Exploding converters are rare, leaking ones not so rare. Aluminum ones cannot be welded since the rivets are steel and the converter is aluminum. But there are venders who rebuild them to fix the leaks. If you have the steel converter with the riveted hub (like Shevegel), then it can be welded to fix the leaks. The latest version, is a steel converter with a welded hub from the factory (best one).
Joe Alexander
Blacklick, Ohio
1969 Dark Olive 280SL
2002 ML55 AMG (tow vehicle)
2002 SLK32 AMG (350 hp)
1982 300TD Wagon turbo 4spd.
1963 404 Mercedes Unimog (Swedish Army)
1989 flu419 Mercedes Unimog (US Army)
1998 E430
1974 450SLC Rally
1965 220SE Finback