722.303 in bits photo shoot

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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 (http://www.peachparts.com/shopforum/diesel-discussion/304903-722-118-automatic-transmission-rebuild-monster-diy.html). 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

http://www.peachparts.com/shopforum/mercedes-parts-reference-library/273540-transmission-722-303-general-service-parts-list.html

http://www.peachparts.com/shopforum/mercedes-parts-reference-library/317111-transmission-722317-02-951413-general-service-parts-list.html

http://www.peachparts.com/shopforum/tech-help/308281-help-stuck-road-722-3-no-3rd-4th-gear.html

http://www.peachparts.com/shopforum/tech-help/278442-94-e320-transmission-rebuild.html

http://www.peachparts.com/shopforum/general-information/319957-722-315-pump-re-seal-pictures.html

http://www.peachparts.com/shopforum/diesel-discussion/311766-trans-failure-question.html

Good pictures in this thread

http://www.peachparts.com/shopforum/diesel-discussion/307031-91-300d-trans-stuck-1st-gear.html


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.


http://www.peachparts.com/shopforum/general-information/311136-fsm-epc-data-%3D-chassis-model-transmission-drive-train-information.html


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!

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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

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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!


http://www.peachparts.com/shopforum/2787565-post9.html



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

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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.

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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.

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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.

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After trying it the other way, I found it easiest to tip the transmission on to its bell housing / front end for this bit – be careful of the input shaft.








Whilst the rear cover is still in place, now is a good time to remove the output shaft seal





Remove rear cover





The crud in the bottom of the rear cover shows how badly maintained this transmission has been.

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Remove the park system








There are shims under this part that you ideally need to keep





It looks like this transmission has been removed and stored vertically with the tail end pointing up in the rain! As you can see in the pictures above this part of the transmission is pretty rusty - even the shims under this splined part to which the park pawl engages are rusted. There's rust on the governor as well...


...I have no knowledge of the history of this transmission. It was at least sold to me honestly as spares – I did get the impression from the (private) seller, however, they had had a rough time with it. There was no longer a Mercedes to be seen at their house...

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Remove the drive cog for the governor and the secondary / auxiliary pump.





Remove the cir-clip and pump parts for the secondary pump.

Please note - there should be a small ball bearing between the outer cap and the cover for the end of the spring. Mine was missing.





Remove little nut with plastic locking from the shaft with a slot in the end








You can now remove the governor and the cross shaft that connects to the secondary pump.


An important part of this system which looks like it is clogged is this little spray tube that delivers oil to the governor / secondary pump gear system.

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Remove the front pump assembly







Remove the push rods that are between the lugs on the brake bands and the brake band pistons and remove the B1 brake band. It is quite easy to pull out the B1 brake band and also the B1 brake drum.





I found that the B1 brake band was worn down to the metal – virtually no friction material left – consequently the B1 brake drum is badly damaged. The K1 clutch is inside this drum.


Here's a picture of the push rods on the B2 brake band.




You can now remove what they (sometimes bizarrely) call the B3 clutch pack. I guess this terminology is a throw back to the 722.1 that actually had a brake band – here reverse is controlled by a clutch. I'm surprised it isn't called the K3 clutch – hey ho let's go with the flow(?). Does anyone know why it has been named this way?

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Remove the screws at the rear of the casting and pull out the rest of the gear set





Here's a picture showing how the B2 band is left in place. You can't withdraw it until the gear set has been removed.





To remove the B2 band you need to twist it round and pull is through the casing.

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This is a work in progress thread. At the moment I'm no further than the photographs show. I plan to strip it all down and work out how much money it would cost to repair – this information should be of interest to others. I doubt if I'll have the funds to finish it in the near future. I've really got to get my W123 back on the road first. This transmission is just a play thing...

[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.

[Stretch]

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]

Originally Posted by Army

This is a work in progress thread. At the moment I'm no further than the photographs show. I plan to strip it all down and work out how much money it would cost to repair – this information should be of interest to others. I doubt if I'll have the funds to finish it in the near future. I've really got to get my W123 back on the road first. This transmission is just a play thing...

.

well done Army !!

I'm sure that this one also will be awesome thread.


cheers
ChO


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