722.303 in bits photo shoot - PeachParts Mercedes-Benz Forum

Stretch · #1 08-19-2012, 05:14 AM

G'day Folks,

About a year ago I bought a 722.303 for not very much money. I found it whilst looking for parts for my 722.118 which has now been rebuilt (722.118 Automatic transmission rebuild (Monster DIY)). The 722.303 was sold to me “for spares” and I got it on a whim thinking that I might be able to do something with it.

I've talked about this 722.3 transmission that has been sitting my garage for quite some time now – finally this weekend I got some time off for good behaviour; so I started a strip down to see what is wrong with it. I've found a few pretty expensive to fix problems with it, so at the moment I'm not sure if I'll be carrying on with the rebuild just yet. If, however, I win the lottery, or some non existent rich uncle leaves me some dosh, or someone donates the parts(!) I'll carry on with the rebuild ASAP!

Unlike the 722.1 transmission the information for the 722.3 is readily available so this time I'm not doing an in-depth write up like I did for the 722.118 (see link above). It takes too long and it isn't worth while. This time I'm just doing pictures and a few comments.

Please JOIN IN with the thread – ask questions – request information – I'll do what I can to make this thread a good one but if I can get some help this time I'll be a happy chap.

To find more information about the 722.3 the following links might be of help

http://www.ganzeboom.net/images1/ganzeboom/parts/Mercedes/722.3,%20722.4.pdf

Transmission 722.303 general service parts list

Transmission 722317 02 951413 general service parts list

Help - stuck on road 722.3 no 3rd/4th gear

94 E320 transmission rebuild

722.315 Pump Re-seal pictures

Trans failure question

Good pictures in this thread

'91 300D trans stuck in 1st gear...

I encourage everyone who wants / needs to take their transmission to bits to read the ATSG manual (which can be found quite easily). If you can get hold of the German version W123 / W126 FSM on CD you'll find loads of great pictures and a very detailed description of the procedures you need to do. You do need to speak German though or cut and paste information into an on-line translator and then work out what the %#$&**% it should really mean! The best thing about the German version of the FSM is that is contains tuning data that YOU WILL NEED when you get the transmission back in the car.

Please note - I've posted this thread in DD because the 722.303 is for a 300SD and a W123.193 300TD. As I go through the strip down I'll be pointing to the parts (if any) that are uniquely “diesel”.

If you want more information about which transmission went where at the factory I've been slowly compiling that kind of information here.

FSM + EPC data => Chassis / model / transmission / drive train information

One last comment before the thread begins proper – my reason for starting this thread, for making the effort (again) is to try and encourage you all to fix your transmissions. When you start they are a really daunting DIY but honestly after your first transmission you'll be thinking – just like me - “what's all the fuss about? They are easy to do!” I feel that I'm approaching the stage where they're getting a bit boring now...

...so come on if I can do you it – you can do it too!

Stretch · #2 08-19-2012, 05:15 AM

Here's a picture describing the relationships between the elements of the 722.3 transmission and the gearing

Please note - I think this diagram showing the relationships between each element and the gears is a bit misleading for someone who is familiar with the 722.1XX. B3 is not a brake band in the 722.3 it is a clutch at the front of the transmission.

Here are some pictures showing the position of certain parts on the outside of the transmission

Stretch · #3 08-19-2012, 05:16 AM

Unlike the 722.1 transmission the input shaft on the 722.3 extends out from the casing – to “up end” the transmission on the “bell housing” part you need to support the casing so that the input shaft does not get hurt. I used blocks of wood.

First I removed the output shaft nut. Someone had already had a go at it before I bought the transmission but failed... (Not a good sign)

I used the same method as I did on my 722.118 as I'm still not going to buy a special tool for that!

722.118 Automatic transmission rebuild (Monster DIY)

I could tell that the bearing in the rear part of the casing was dead.

Once you've got the rear nut off remove the stuff on the outside of the transmission, such as the selector shaft, the “electrics box”, kick down solenoid, vacuum dash pot

Stretch · #4 08-19-2012, 05:17 AM

Unlike the 722.1 you need really deep clamps to press the covers in so you can remove the cir-clip ring wires (LINK). I don't have clamps that are deep enough so I removed the valve body.

You need to remove all of the bolts that you see. Warning – there are no other bolts or screws holding the layers of the valve body together – it is not like the 722.1 valve body that can be removed in one safe unit. EDIT => It isn't as bad as I thought there are two screws on the underside of the valve body that will stop most of the parts from flying all over the place. You can loose a piece though if you are not careful.

With the whole of the valve body removed you can look through to what seems to be a weak point with these transmissions – the governor drive shaft.

The shaft on this transmission is almost dead.

Stretch · #5 08-19-2012, 05:17 AM

I've read that lots of people just yank the Bowden cable conduit out of the transmission. I can see why people do this – as who would want to remove the valve body to gain access? I can also imagine that if you do do this you'll either break the conduit doing it or weaken it to such an extent that it will no longer seal properly and leak after you've “fixed it”. It is a difficult part to remove with care – bayonet fittings are great for fitting but a pain in the arse to remove.

Stretch · #6 08-19-2012, 05:18 AM

Here's the B1 piston coming out

The B2 piston (as always) was being a bit stubborn – but I worked out you don't really have to worry about it to get the gear set out so I left it in place. B2 to come later.

gottarollwithit · #7 04-12-2018, 05:01 AM

Thread blast from the past.

I have a leak on the drivers side of the trans. It's coming from forward of the vac dash pot, but rear of the cooler line hole. What is that circular plate that accepts a hex key?? What's behind it?.. it is on TIGHT. I'd like to somehow fix the leak....

Quote:

Originally Posted by Stretch

Here's a picture describing the relationships between the elements of the 722.3 transmission and the gearing

Please note - I think this diagram showing the relationships between each element and the gears is a bit misleading for someone who is familiar with the 722.1XX. B3 is not a brake band in the 722.3 it is a clutch at the front of the transmission.

Here are some pictures showing the position of certain parts on the outside of the transmission

toomany MBZ · #8 08-19-2012, 05:53 AM

Thanks Army, great work.

I have a Superior Shift Kit for the SD (722.303).

I hope to install new, stronger K1 and K2 springs at some point.

If you get the chance, post a few pics (^).

My garage doesn't have a lift and I'm not comfortable working nearly blind and over head lying on a creeper.

Stretch · #9 08-19-2012, 06:04 AM

Quote:

Originally Posted by toomany MBZ

Thanks Army, great work.

I have a Superior Shift Kit for the SD (722.303).

I hope to install new, stronger K1 and K2 springs at some point.

If you get the chance, post a few pics (^).

My garage doesn't have a lift and I'm not comfortable working nearly blind and over head lying on a creeper.

I'll definitely do pictures of the valve body in bits - I want to try and identify each part if possible. I have quite some investigative work to do...

cho · #10 08-19-2012, 10:39 AM

Quote:

Originally Posted by Army

I feel that I'm approaching the stage where they're getting a bit boring now...

.

No, you don't

.

charmalu · #11 08-19-2012, 11:27 AM

Here`s Army blindedly leading his troops

into the unknown, slaying Dragons and Demons

that lurkith with in his Puddle Jumper

, writting yet another chapter in his book

of knowledge, and his constant pursuit of daily DIY

to be conqured.

Thanks Professor

great job.

Charlie

engatwork · #12 08-19-2012, 11:31 AM

Good job.

Stretch · #13 08-19-2012, 11:43 AM

Thanks for the kind words folks.

I didn't get much of a chance to do anything today. I just took some pictures of the damage.

I've got a feeling this transmission will be a rubber necker's paradise.

First off here's the worn to the metal B1 brake band

I reckon they should have kept on driving it to see if it would eventually polish to a mirror finish.

Here's probably why the output shaft felt a bit rough

Really nasty pitted surface on the bit where the park pawl fits (I'll have to RTFM and find out what it is actually called!)

Rusty governor

It also has some spectacularly sharp edges on the drive cog. As does the cog that goes on the output shaft.

Look closely in the picture above - the middle part of the teeth are sharpened (by wear) - they are thinner than the outer edges.

I think I might have to ask the moderators to rename this thread to "what can possibly go wrong with a 722.3!"

Stretch · #14 08-19-2012, 11:47 AM

I've found lots of this type of debris in the back part of the transmission.

At the moment my guess is that these long thin springs were at one time in the governor.

compu_85 · #15 08-19-2012, 01:41 PM

Thanks so much for the photos! I have a question for you:

I want to do the checks described here: http://www.europeantransmissions.com/Bulletin/DTC.merc/97-20.pdf

It looks like that's the side of the valve body facing the filter. Does the valve body need to come off to do those checks?

Thanks,

-J