Author Topic: Automatic geaxbox, how to disassemble from the car?  (Read 5704 times)

geiz

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Automatic geaxbox, how to disassemble from the car?
« on: 13 July 2009, 10:57 PM »
The automatic gearbox of my '73 450SE is leaking a large amount of oil. It is coming from behind the torque converter, from the inner side.
I have to remove the complete gearbox, but how?
It seems impossible for me to remove the upper bolts (which connects the gearbox with the engine) and the drive shaft without special tools.

I don't have wrenches in the size 42 and 46, is there another way to remove the drive shaft? And what tools are you guys using to detach the upper gearbox bolts?

Thanks!
450SE - 1973 (Plaything)
350SE - 1973 (Spare parts)

Big_Richard

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Re: Automatic geaxbox, how to disassemble from the car?
« Reply #1 on: 14 July 2009, 02:41 AM »
the upper bolts can be removed with a ring spanner from the engine bay, its hell not easy but its possible.

you are supposed to use a couple long extensions with a universal joint or 2 from the bottom. It requires 2 people, one under the car, and another to get the socket on the bolt in the engine bay...

I just used a large adjustable spanner to undo the centre nut on my tailshaft to collapse it for removal.

TJ 450

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Re: Automatic geaxbox, how to disassemble from the car?
« Reply #2 on: 14 July 2009, 02:51 AM »
On a 450, the upper bellhousing bolts are readily accessable from the engine bay with a ring spanner (box wrench) as PB mentioned. There's lots of room with an M117. ;)

You will need to undo the three pairs of 13mm bolts attaching the torque converter to the driveplate before you attempt to separate the bellhousing and the torque converter must remain attached to the transmission to prevent damage. The torque converter may need to be levered rearwards as the spigot may be seized in there.

If the flex discs are original, all you need is two 19mm ring spanners and you probably don't even need to undo the centre nut on the driveshaft (I didn't). You will need to remove the tailshaft complete, though, taking car not to separate the halves. Otherwise it will be in the way.

Tim
1976 450SEL 6.9 1432
1969 300SEL 6.3 1394
2003 ML500

geiz

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Re: Automatic geaxbox, how to disassemble from the car?
« Reply #3 on: 14 July 2009, 10:59 AM »
Thank you very much for the reactions.
So I didn't think in a wrong way, it is really a hell of a job to do.

But I didn't understand how to remove the driveshaft completely? I have just loosen the bolts of the flex disks, but there is an shaft also inside the flex disks, where it stucks on.

And I need to disconnect the 3 13mm screws from the flywheel to the torque converter, so that the torque converter can stay inside the gearbox during removal of the gearbox?

So I need to be more patiently and just go on.... and on ;-)
« Last Edit: 14 July 2009, 01:43 PM by geiz »
450SE - 1973 (Plaything)
350SE - 1973 (Spare parts)

co450sel

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Re: Automatic geaxbox, how to disassemble from the car?
« Reply #4 on: 14 July 2009, 01:38 PM »
This is not a fun job at all.

Should I ever do it again, I would just pull the engine a transmission as one piece.

To get the driveshaft off, I had to separate the flex discs, after pulling the bolts, you need to pry them off the mounting yokes with a screwdriver, then that large nut on the driveshaft needs to be loosened so that the shaft can slide back and forth, I then had to drop the carrier bearing as well to have enough room to maneuver the driveshaft out.

There are 6 bolts that hold the torque convertor to the flexplate that are accessed through a tiny hole at the bottom front of the transmission coverplate. You need to remove these before you remove the transmission crossmember and allow the tail of the transmission to drop, otherwise the bolts get blocked by the engine crossmember. You must remove the torque converter with the transmission, otherwise, the nose of the converter will likely break.

I removed the upper bolts with an extension and universal joint. They are easier to get to after you let the tail of the transmission to drop down.

Getting the transmission out is the easy part.

Putting it back in is horrible.

The torque converter is on a set of stepped splines on the input shaft of the transmission. When putting the transmission back in, the converter needs to be aligned with the holes in the flexplate before the bellhousing bolts can be tightened all the way. This leaves a gap in between the bellhousing and engine block. If you tighten the flexplate to converter bolts all the way when this gap is still present, the converter will be dragged off the end of the first set of splines on the input shaft. You won't notice this until you tighten the bellhousing bolts and the torque converter is jammed against the something and the engine won't turn. So you have to carefully tighten the flexplate bolts a little at a time and then tighten the bellhousing bolts a and then tighten the flexplate bolts some more and so on until everything is tightened all of the way.  All the while you need to try and spin the engine with a ratchet on the crank bolt  an infinitesimally small amount  to try and align the flexplate bolt holes with the tiny window in the front cover.


I hope this makes sense. If not, feel free to ask any questions.

-Justin

geiz

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Re: Automatic geaxbox, how to disassemble from the car?
« Reply #5 on: 14 July 2009, 01:53 PM »
Thank you for this extensive explanation.

It doesn't make me happy, the only way to enjoy this car finally is just to do it. (working already 6 months on it!)  :-\
We do a transmission swap several times on other cars, but normally it takes 2-3 hours to complete the whole job.
The construction on this Merc. is crazy.

I'll keep you up to date about the progresses  ;)

450SE - 1973 (Plaything)
350SE - 1973 (Spare parts)

geiz

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Re: Automatic geaxbox, how to disassemble from the car?
« Reply #6 on: 24 July 2009, 04:23 AM »
We have removed the gearbox finally yesterday.
(We think that the cause of the leakage was the oil seal ring between the torque converter & the gearbox. It looks like it was moved backwards, popped out of the recess in the gearbox.)

My question is, how is it possible to change the oil seal ring?? There is a metal ring in front of it, on the same axle/tube.  (I will post a picture of it today) I can cut that ring and remove it and put a new seal inside the gearbox and pull the torque converter back on it.
Or I can put a new seal around the axle of the torque converter and put a new metal ring on it. But ... I think it is impossible to assemble it in this way, because the seal will be pulled back.

Can someone tell me how to do it in the right way?

Thank you very much!
450SE - 1973 (Plaything)
350SE - 1973 (Spare parts)

Big_Richard

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Re: Automatic geaxbox, how to disassemble from the car?
« Reply #7 on: 24 July 2009, 05:48 PM »
the front pump has 2 seals, 1 o-ring around its cast iron body, and the other one is the radial seal ring you see with shaft comming thru the centre of it.

You must remove the bell housing/front cover to remove the pump and change *both* seals. You will see the bolts for the pump on the reverse side of the bell housing. When reinstalling the front cover, ensure you use a new gasket.

While the transmission is out, i would at bare minimum, replace all the servo lip seals & casing gaskets & seals. I would also replace the rear output shaft seal.

« Last Edit: 24 July 2009, 05:57 PM by Patrick Bateman »

geiz

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Re: Automatic geaxbox, how to disassemble from the car?
« Reply #8 on: 27 July 2009, 03:13 PM »
Thank you for this clear answer.
The bell house is seperated now from the gearbox and the primary pump is out of it.
But the shrink ring around the torque converter shaft (with the oil seal ring behind it) was stuck. Heating it up wouln't help.
Finally it breaks and popped off.
Is this ring important and possible to get at a shop?


See photos:



450SE - 1973 (Plaything)
350SE - 1973 (Spare parts)

Big_Richard

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Re: Automatic geaxbox, how to disassemble from the car?
« Reply #9 on: 27 July 2009, 03:31 PM »
i wouldnt of touched the torque converter, the seals you need to change are in the front transmission pump only - MB dont sell any parts for refurbishing the torque converter, only the complete unit, which is going to be very expensive. You may need to obtain a good second hand one or get that one remanufactured now.

That converter has a discounted price of $5090US, hopefully you can find a used one quite easily.
« Last Edit: 27 July 2009, 03:39 PM by Patrick Bateman »

TJ 450

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Re: Automatic geaxbox, how to disassemble from the car?
« Reply #10 on: 27 July 2009, 07:19 PM »
Is that ring not the bearing from the front pump? What about the other part beneath it, is that the radial seal? If that is the case, there is something very wrong with how that came out.

There shouldn't be anything attached to the torque converter at all.

If that is the bearing sleeve, then I would be concerned as to how that ended up seized on there. It should remain in the pump along with the radial seal.

Something to be aware of is that the surface of that spigot is critical for proper sealing--- it must remain perfect.

Worst case scenario is that you will need a new (replacement) front pump and torque converter.

However, if the bearings were seized in the front pump then I would be concerned for the rest of the trans.

Hopefully it's not as bad as it seems and will all work out OK. :)

Step one is to remove the bearing sleeve along with the radial seal from the torque converter. Then you will have to inspect everything, including pulling apart the front pump. I think you will find that the pump is stuffed, so you will probably need to obtain a junk transmission with torque converter. A 280 four speed would even be OK, unless you plan to overhaul the whole thing now.

Tim
« Last Edit: 27 July 2009, 07:28 PM by TJ 450 »
1976 450SEL 6.9 1432
1969 300SEL 6.3 1394
2003 ML500

geiz

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Re: Automatic geaxbox, how to disassemble from the car?
« Reply #11 on: 28 July 2009, 07:49 AM »
The seal on the picture (below the broken iron ring on the shaft) is really the front radial seal of the oil pump. This was how it came out of the transmission when I removed the torque converter.

The bearing inside the oil pump housing is in a very good condition without play. All parts inside the pump are undamaged and looks like new. This is also for the visible parts (with the bell house removed) inside the gearbox.

I think the only function of the iron ring is to keep the radial oil seal on it's exact location??
Maybe there are some different models?
I will make more pictures of it this evening and post it on the forum, so you guys can see it and consider ;-)
450SE - 1973 (Plaything)
350SE - 1973 (Spare parts)

TJ 450

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Re: Automatic geaxbox, how to disassemble from the car?
« Reply #12 on: 28 July 2009, 09:24 AM »
Pics would be good. :)

As you said earlier, installing the seal like that is impossible. That ring is not supossed to be there. The only place it could have come from is inside the pump, as there are two bearing rings inside the pump... although when you post the pics, it should be clear what's going on. ;)

Tim

Edit:

I believe item 51 is your ring. This and 53 are both bushes from inside the pump. They are both critical to the proper operation of the pump, as they are the bearings. Item 52 is the radial seal.

« Last Edit: 28 July 2009, 09:33 AM by TJ 450 »
1976 450SEL 6.9 1432
1969 300SEL 6.3 1394
2003 ML500

geiz

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Re: Automatic geaxbox, how to disassemble from the car?
« Reply #13 on: 28 July 2009, 01:54 PM »
Mine looks a litte bit different, not so much rings and seals inside the pump.
More like this picture:



But nothing about an iron ring.

I have measured, de inner of the pump (where that ring was inside) is a little bit more than47mm. The diameter of the shaft is 44mm. The iron ring is 1.5mm thick. So there is a very small gap in between. I think you're conclusion is right, that this is an bushring. See my pictures here below. The only weard thing is, that it is an very soft material?

Should it be possible to  order it at the mercedes dealer?

« Last Edit: 28 July 2009, 01:59 PM by geiz »
450SE - 1973 (Plaything)
350SE - 1973 (Spare parts)

geiz

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Re: Automatic geaxbox, how to disassemble from the car?
« Reply #14 on: 28 July 2009, 02:03 PM »
























450SE - 1973 (Plaything)
350SE - 1973 (Spare parts)