K1, K2 and B1 722.4 valve replace - PeachParts Mercedes-Benz Forum

spock505 · #1 07-22-2016, 08:14 PM

Being a bit 'needy' at the moment so bear with me. Lots of DIY project lined up so going through the process of ordering parts/tools ect..

Having read most of the threads on this subject I was fairly confident on what was what, that was until it came to ordering - anyone that has ordered these bits probably knows they are only listed under another model, to find them my MB dealer followed one of the threads on here to access part numbers.

Parts have now arrived so wanted to run a quick check as to their roles.

K1 - part number A 126 270 44 77

This replaces the internals (not the outer case) for K1 valve located to the right next to B1

Okay, this is where it gets a bit tricky as not sure which one is K2 or B1 - as they are different colours my approach here would be to match like for like on removal.

K2 or B1 - part number A 126 270 04 35

K2 or B1 - part number A 126 270 05 35

Thanks all.

spock505 · #2 07-22-2016, 08:18 PM

Just to add, both of those kits two kits do say K2, but detailed afterwards 'Trans piston Kit' or 'Valve body' ?

Stretch · #3 07-23-2016, 05:22 AM

I can't tell for sure as I've not had a 722.4 valve body to bits before. However - and I could be wrong about this so don't panic if you are indeed that "needy"! - I've got a feeling you've got two parts for one bit. I think you only get one of those big sliding things for each of the actuating mechanisms...

...some of the positions for things might be comparable with the 722.303 valve body I took apart here =>

722.303 in bits photo shoot

This is at least a valve body for a "diesel" transmission (meaning transmissions for petrol engines are often a bit different). May be there are enough similarities in that information to help you make an educated guess?

spock505 · #4 07-23-2016, 06:28 AM

Quote:

Originally Posted by Stretch

I can't tell for sure as I've not had a 722.4 valve body to bits before. However - and I could be wrong about this so don't panic if you are indeed that "needy"! - I've got a feeling you've got two parts for one bit. I think you only get one of those big sliding things for each of the actuating mechanisms...

...some of the positions for things might be comparable with the 722.303 valve body I took apart here =>

722.303 in bits photo shoot

This is at least a valve body for a "diesel" transmission (meaning transmissions for petrol engines are often a bit different). May be there are enough similarities in that information to help you make an educated guess?

Thanks bud and good tip:-

"some of the slotted heads on the screws were burred. To avoid this from happening to you, my advice is to not use normal screw drivers but to use a bit and a 1/4" drive ratchet."

This is the excellent (cheers DieselPaul) thread myself and very helpful MB parts chap followed:

722.4 K2 Spring Part Number

tbh we have ordered the exact same as DieselPaul which is okay given we don't know the parts for K2 until removed, however it doesn't cover B1 which was my mistake.

Helpful layout pictures from MB org, thanks -

So in short, it looks like I don't have the B1 valve - hopefully the K1,K2 will be enough to reduce/eliminate flare.

P.S is there anything you haven't taken apart

Stretch · #5 07-24-2016, 01:52 AM

Quote:

Originally Posted by spock505

...

P.S is there anything you haven't taken apart

In the big scheme of things there's a lot of stuff that is just begging for it - fortunately I only dismantle my own stuff!

spock505 · #6 07-25-2016, 05:32 PM

Just checking a few things before starting job tomorrow.

The flux capacitor shown here in a fetching orange hue, can you alter the vacuum by twiddling the white cap or does it have to be removed accessing the 'T' bar ?

..ta folks

Stretch, maybe think about setting up a Euro version of Mercedes Source, your attention to detail is superb.

Stretch · #7 07-26-2016, 02:43 AM

Quote:

Originally Posted by spock505

Just checking a few things before starting job tomorrow.

The flux capacitor shown here in a fetching orange hue, can you alter the vacuum by twiddling the white cap or does it have to be removed accessing the 'T' bar ?

..ta folks

Stretch, maybe think about setting up a Euro version of Mercedes Source, your attention to detail is superb.

The T bit pulls out slightly to allow you to change the setting

spock505 · #8 07-27-2016, 05:24 PM

Cheers for that, K1 duly removed but started to rain - nipped pan back up couple of bolts until clear, worried about damp.

Stretch · #9 07-27-2016, 10:04 PM

Quote:

Originally Posted by spock505

Cheers for that, K1 duly removed but started to rain - nipped pan back up couple of bolts until clear, worried about damp.

I hate working in the rain too.

Don't get too concerned about humidity and the transmission though - there's a vent on the top of the casing that lets the outside world's atmosphere in. Do get worried about wind! Wind is bad and will blow lots of abrasive muck inside a transmission...

spock505 · #10 07-28-2016, 08:52 PM

Quote:

Originally Posted by Stretch

I hate working in the rain too.

Don't get too concerned about humidity and the transmission though - there's a vent on the top of the casing that lets the outside world's atmosphere in. Do get worried about wind! Wind is bad and will blow lots of abrasive muck inside a transmission...

Cool, thanks K2 removed which matches up with the blue one purchased (packet parts numbers are different as highlighted in previous posts).

Even though I pulled about 2.3 liters of ATF with vacuum pump another liter resides within the filter, keeps dripping until removed which is needed anyway to access K2 screws.

What I didn't allow for was the new ATF (changed at less than 1k) being somewhat old looking, almost brown similar worn ATF.

In addition the sump and filter had a grey silt coating of what I assume to be build up being released. Ordered 5 liters of ATF so not enough for a full flush which it needs, but I may take another liter out the TC and put 5 back, order new filter and ATF after say another 1k and replace.

Going to check vacuum system tomorrow, does the white cap on the modulator just pop off, mine seems to spin without doing anything, i.e finding a recess allowing removal.

Cheers.

spock505 · #11 07-28-2016, 10:27 PM

Just thinking out aloud, is it worth removing the B1 valve whilst stripped down, ordering sufficient ATF and new filter.

My concern is the K1 and K2 replacements may not solve the 1 - 2 flare/hard-ish shift which might be down to B1?

Currently struggling to access MB.org web site (HATTENATOR 'how to') advertising overload.

At least this way i can get the correct part number for B1 which can be problematic from EPC.

Stretch · #12 07-29-2016, 01:33 AM

Quote:

Originally Posted by spock505

Cool, thanks K2 removed which matches up with the blue one purchased (packet parts numbers are different as highlighted in previous posts).

Even though I pulled about 2.3 liters of ATF with vacuum pump another liter resides within the filter, keeps dripping until removed which is needed anyway to access K2 screws.

What I didn't allow for was the new ATF (changed at less than 1k) being somewhat old looking, almost brown similar worn ATF.

In addition the sump and filter had a grey silt coating of what I assume to be build up being released. Ordered 5 liters of ATF so not enough for a full flush which it needs, but I may take another liter out the TC and put 5 back, order new filter and ATF after say another 1k and replace.

Going to check vacuum system tomorrow, does the white cap on the modulator just pop off, mine seems to spin without doing anything, i.e finding a recess allowing removal.

Cheers.

I can't remember off hand how much is left in a transmission after all the ATF has been drained but it is quite a bit.

It sounds like the whole valve body could do with being stripped down and cleaned. What you are experiencing is why all of those additives and the advice given by people to use them is bollocks: Stuff / muck / **** gets stuck in the valve body - it won't "flush" out!

The only way to get this muck out is to strip and clean.

Quote:

Originally Posted by spock505

Just thinking out aloud, is it worth removing the B1 valve whilst stripped down, ordering sufficient ATF and new filter.

My concern is the K1 and K2 replacements may not solve the 1 - 2 flare/hard-ish shift which might be down to B1?

Currently struggling to access MB.org web site (HATTENATOR 'how to') advertising overload.

At least this way i can get the correct part number for B1 which can be problematic from EPC.

If I were you I'd be speaking with the friendly guy behind the parts counter at the local dealership...

spock505 · #13 07-29-2016, 01:48 AM

Apart from these valves not being listed on EPC under VIN numbers, there is also added confusion as to part numbers ordered v what arrives.

K2 worked out okay as detailed previously.

Stretch, going to refit K2 but also remove B1 and check part number, there's always a remote chance the remaining (light blue) valve may fit but doubt it.

If it doesn't, refit reassemble checking modulator operation too, refill with around 3.5 liters of new ATF and hope this cures 2-3 and 3-4 hard-ish flare. If so, this bodes well for replacing B1 along with full flush and new filter.

Cheers,

spock505 · #14 07-30-2016, 01:03 AM

Okay, carried out the above refitting whilst checking B1 part number below.

This number is very different from the actual part order number, 126 270 02 35 on EPC - that said, I can now ask friendly MB parts person to check once arrived and compare, no hit and miss removing the tranny and ATF.

Whilst under there I removed the modulator cap which looks like this:

Not sure if those little teeth are there to lock the T bar pin underneath or it adjusts the pin without removal - any ideas?

Anyway, I turned it a 1/4 turn to the left to see if it would help soften the shifts, bit annoyed at myself as I should taken the car for a test drive first to see if K1,K2 change worked by itself.

The end result however was a big improvement, no flare or hard shift on 2-3 or 3-4 very smooth, although still need to stop myself backing off the peddle anticipating flare.

1-2 shift greatly improved but still there, the improvement could be the modulator quarter turn with the underlying issue (B1 still present).

My thoughts are that if K1, K2 were worn out B1 is probably too, hence no dramatic improvement as with other shifts.

Is it correct to think the modulator only affects the hardness of the shift, not flare?

On another note, bearings and kits have arrived - will post up a bit later on that (all looks good so far).

spock505 · #15 07-30-2016, 09:14 AM

Quick update for anyone contemplating this job, in summary well worth while for cost involved.

Spent the morning tweeking the modulator/bowden cable until super smooth, kick down works as should too, under load and foot to the boards.

Just for info, on the orange type modulator the cover will provide fine adjustment within 360 degrees or slightly less, beyond that it needs to be removed.

Next on list, bushes and bearings.. and the odd joint..no, not that type of joint

, the ones holding LCA to wheel hub..