Transmission leak 450SE

[Em86]

I´ve noticed that my 450 is leaking transmission oil. Leak is not big, the car is usually not driven for winter time and its propably why it´s leaking. It has only 199000km so it has been not driven much.

Is there some usual place  where these older transmissions leak? How many seals does the transmission have?

I havent figure out the transmission number yet, is it located somewhere in the passenger side?

Thanks for help!

[rumb]

Do you have a general idea where it is leaking?  front seal, rear seal, hose connections, or elsewhere?   

Give it a good washing and then start looking for leak area.

[daantjie]

Multiple places they can leak.
As rumb suggested a thorough clean is the place to start.
Transmission number is on passenger side above the pan.

[Em86]

Yes I did clean it as good as I could get and the only place I found some sort of wetness was inside the red circle. The picture is not from my car, just found on the net.  So that´s the drain plug right? But there´s propably no seal? Just copper ring? I just dont think thats where the leak is coming from....

[daantjie]

That is a 6.9 transmission but the connection should also be on yours. That is where the dipstick tube connects.
That is a banjo fitting with one washer to seal on either side of the fitting. Could be leaking here. Easy fix just replace the crush washers.

[Em86]

Have to check it out. The car is now on winter-hold so I can figure it out about a month.

It would  certainly be the easiest if this is the leak. Propably it isn´t. It´s a little worrying to know that the car is 42 years old. Could be any seal...

[rumb]

Just be prepared, when you remove that line all the trans fluid will also want to come out.......

Good time to just change the filter, pan gasket and fluid.

[Em86]

Okey, a little more  on my leaking 450SE transmission.

There was wetness in these two bolts (red) that hold the pan in place. I cleaned the gearbox with brakecleaner and start to search for a leak. Didn´t find anything. Then I noticed that when using brakecleaner to the rod that connect to the gear shifter (??) (yellow), it does gets down to the back bolt. So I can assume that there is some leaking coming from that shifter rod on the passenger side.

Its possible to order a seal set for my transmission but it costs almost 600€......So I was a little bit down but there are at least seals available.

[tcj]

yes, thats a common leak.
Early transmissions for the W116 have no seal there, but late transmissions do have a seal.
The seal can only be replaced from the inside, so you have to remove and dismantle the transmission.

Early transmissions without that seal can be upgraded, but the rod (blue circle) needs to be changed then.

But there is a trick:
you can see the white washer in my picture (red circle). Place a suitible o-ring between the white
washer and the housing. This will prevent the oil from leaving the transmission for quite a while.
Can be done without removing or dismantling the transmission.

But be very very cautious: use only an o-ring with small cord thickness: if it is too big then the linkage will
get too stiff which results in the engine remaining in high rpm even if you release the gas pedal. Danger!
So do this only if you have understood the possible consequences and know what you are doing.
And tripple check that the linkage is moving as light as before.

While you are at it: check all joints of this linkage (and the linkage on the other side of the transmission),
I am sure the plastic joints are gone resulting in too much play in the linkage.

Thomas