722.001 transmission pump "O" ring seal replacement

I plan to replace the pump "o" ring as well as the front and rear main seal on my transmission this winter, has anyone tried this or have a "how to"?

Hello Jim, our member wusel-53 -Thorsten- did this last month. he had his fair share of trouble, related to torque converter. Here is the link.
sternzeit-107.de/de/forum/forum-107/2408...be-us-380-sl?start=0

Rudiger

Hi Jim,

does your car has 3-gear or a 4-gear transmission? If it’s equipped with a 722.x-version please renew the 4 friction disks for the reverse-clutch as well.
I can highly recommend to pay attention during the of the removal old of the old paper gasket. Don’t allow any debris or small particles to enter the oil channels in the transmission mainframe!!!
A very good Overview to the 722.x you can get by browsing this PDF
up.picr.de/27948585jo.pdf
To change the O-ring you have to disassemble the main oil pump, re-installing the big piston needs a bit attention and a plan how to get the piston together with its seal back in place, but thats no rocket-science, only a bit tricky.
A major hint before you really start is to loosen the nut at the driveshaft (in most cases you need a "long socket" 32mm) when the transmission is still in place in the car. So you don’t need to hold anything. Just shift to “P” and untighten it. The same procedure for tighten this nut: Do it when you have reinstalled the tranny.
At last you need to pay attention when fitting the torque converter to the transmission. I would highly recommend to do this with the tranny in upright position, otherwise you can end up like Thorsten with 2 destroyed oil pumps.

Cheers Martin

PS: You can also check out Youtube and of course our Werkstattbereich

Hi Rudiger, I just read the other thread, wow, Thorsten had some bad luck there.

Hi Martin, thanks for the suggestions, I am not sure I have the confidence to dig deep into the transmission. Lets see how the engine rebuild goes first, then I will see if it is summer again or only spring.

The gearbox is a 3 speed (W3B-050). It had a small oil leak from the bell housing last year, which has stopped after adding some "snake oil". I am not sure if the leak was from the front seal or pump O ring so planned to change both.

The rear nut looks the same as the one on the differential pinion, so should have the socket.

It looks like the three speed is a bit different to the four speed, the pump it attached to the bell housing which can be unbolted to change the O ring.

Three speed, I also read that the transmission repair manual is not available in English which is a pity.



Four speed.

I also found this parts breakdown for the the earlier transmissions.

jpat.co.uk/uploads/1/0/3/5/103549764/58__mercedes_1a_722.pdf

Jim, did you check for the teardown bemzworld?
Rudiger

Just found a full how to there, it covers the seals and o ring on page 5.

www.benzworld.org/threads/w107-transmiss...mmies.2958890/page-5

Wow!

You found a treasure, thanks for this link. To avoid bad luck regarding to mounting of the torque converter, see this pic
www.benzworld.org/threads/w107-transmiss...ead-2958890&slide=42

Cheers Martin

Hi Jim,

Repairing the transmission is not a problem. You only have to be really careful with the torque converter. And if you already open the gearbox, I would replace all wear parts and seals. That is not expensive. I paid € 530 for the parts

Thanks for the encouragement, if all goes well with the engine and I can find a service manual I will have a go with it. Luckily I do have a spare 722.001 transmission that was working fine when I removed it ten years ago.

It is incredible how the value of spare parts has changed over the last ten years. I sold all of this for scrap value, £50 except for the transmission which I kept.



This "running" entire engine and transmission (with a guarantee) only cost me £350 back then. Now you can't get a second hand block for that price!

Hi Jim,
if you are able to completely overhaul an engine, you can do the same with an automatic transmission. But the workshop manual is of course important. In Germany there is the workshop CD (WIS-CD, including Transmission), is there also something in English? In the 107 workshop manual in Sternzeit-107, of all things, the Transmission part is not included.

Please excuse my bad English. Is for household an holliday use only

For some reason the transmission manual is missing from workshop area on Sternzeit-107, it is also missing from the English manual CD I have. I think it may not exist in English. If I can find one in German I will use OCR and then Google to translate to English.