Calling transmission gurus: 1980 300td with 722.1 won't go into 2nd - Page 4 - PeachParts Mercedes-Benz Forum

Zacharias · #1 09-04-2011, 01:42 PM

Quote:

Originally Posted by Army

Nightmare - where are the pictures?

Are you looking for a .118 valve body now?

No I am going ahead and installing the other trans.

The machine screws did not come from the valve body as far as I can see. These are Phillips with tapered heads. The only screws visible on the sides of my valve body are flat heads.

It looks like they came from elsewhere and made their way down there. One is in good shape, the second is badly chewed, the third is just the head (again chewed). So they had an interesting and we can assume lethal journey through the trans.

The metallic paste really gives me pause.

I uninstalled some security software that had gone buggy and am now having browser issues. I can't upload the pics. If you PM me an email addy I will send them.

Stretch · #2 09-04-2011, 01:56 PM

Quote:

Originally Posted by Zacharias

No I am going ahead and installing the other trans.

The machine screws did not come from the valve body as far as I can see. These are Phillips with tapered heads. The only screws visible on the sides of my valve body are flat heads.

It looks like they came from elsewhere and made their way down there. One is in good shape, the second is badly chewed, the third is just the head (again chewed). So they had an interesting and we can assume lethal journey through the trans.

The metallic paste really gives me pause.

I uninstalled some security software that had gone buggy and am now having browser issues. I can't upload the pics. If you PM me an email addy I will send them.

PM sent.

Those screws are most likely the three screws that hold the cover plate on the front input shaft just before the sun cog goes into the front planet assembly (I'm sure you know the one I mean!)...

...they are meant to be fixed in place with LOCTITE...

...I wonder what happens if you don't?

Stretch · #3 09-04-2011, 02:05 PM

Here are the photos from Zacharias (sent via email to me)

Definitely the three screws for holding in the cover for the input shaft

The rod - which doesn't look too altered to me - though I've only opened three 722.1 transmissions so far.

Give that gunk a scrape and see if it reveals some shiny metal... it might be brazing - difficult to see... I'm keeping my fingers crossed - ever hopeful!

Zacharias · #4 09-04-2011, 02:21 PM

Quote:

Originally Posted by Army

The rod - which doesn't look too altered to me - though I've only opened three 722.1 transmissions so far.

Give that gunk a scrape and see if it reveals some shiny metal... it might be brazing - difficult to see... I'm keeping my fingers crossed - ever hopeful!

I rubbed it when it was out and the result is what you see. It had some dark residue on it when it came out.

I didn't worry so much about that. Hearing rattling as you drop a trans pan sort of clouds up your day.....

Zacharias · #5 09-04-2011, 02:06 PM

Quote:

Originally Posted by Army

...they are meant to be fixed in place with LOCTITE...

...I wonder what happens if you don't?

Assuming that is what they are, can you guess at the path they've taken and what they may have ruined?

Pics sent.

rs899 · #6 09-05-2011, 11:37 AM

^^ in anticipation of its publication I am going to collect a large supply of English Ale to enhance my comprehension....

Stretch · #7 09-05-2011, 12:34 PM

Quote:

Originally Posted by rs899

^^ in anticipation of its publication I am going to collect a large supply of English Ale to enhance my comprehension....

That won't help you need to come over here on holiday again and get really immersed in the culture and the slang!

Stretch · #8 09-12-2011, 04:02 PM

That is just $%&^.

I've got some pictures up of the valve body bits in this thread now

722.118 Automatic transmission rebuild (Monster DIY)

rs899 · #9 09-12-2011, 07:43 PM

After you take a valve body apart and marvel at the engineering, you also understand that there is nothing in a can that is going to clean all the silt out of it. See the end of Army's rebuild thread.

Zacharias · #10 09-12-2011, 09:00 PM

Quote:

Originally Posted by rs899

After you take a valve body apart and marvel at the engineering, you also understand that there is nothing in a can that is going to clean all the silt out of it. See the end of Army's rebuild thread.

I am not sure about your reference to 'nothing in a can'. If you mean the use of the Lucas, that was Sunday afternoon desperation.

What I am now speaking about is a transmission shop pressure-flushing it with a machine. If you have a problem with that, please be clear as to why.

Thanks

Zacharias · #11 09-12-2011, 11:57 PM

Could a sticking kickdown solenoid produce these symptoms?

Stretch · #12 09-13-2011, 03:11 AM

Quote:

Originally Posted by Zacharias

Could a sticking kickdown solenoid produce these symptoms?

You said the replacement transmission only works in first and that it "slips like hell in first".

Tackling the stuck in first bit -

Yes I think the kick down system will kick down from second to first (but I'm not 100% sure as first in these gearboxes is hardly usable - especially on the flat - so it might only do a 4 to 3; 3 to 2; or even a 4 to 2... I need to investigate this to be sure.)

This is easy to check just unplug the wire at the solenoid.

Tackling the slipping in first bit -

No the kick down system shouldn't make the gears slip.

Stretch · #13 09-13-2011, 03:18 AM

Quote:

Originally Posted by Zacharias

I am not sure about your reference to 'nothing in a can'. If you mean the use of the Lucas, that was Sunday afternoon desperation.

What I am now speaking about is a transmission shop pressure-flushing it with a machine. If you have a problem with that, please be clear as to why.

Thanks

I think rs899 is saying that if you look at the fine grain silt that I found in the valve body on my transmission and then look at the small spaces in which it exists you can imagine that any product that comes "in a can" is unlikely to clean it out.

I agree with rs899 - no flush - be it a super duper transmission flush at a transmission shop or a high tec especially formulated by NASA monkeys in space solution in a can is going to shift that kind of silt inside the valve body. Why? There isn't enough flow going through the valve body to move it - there are too many dead ends.

However, whether a perfectly clean valve body is the answer to your problem or not is a totally different thing.

Stretch · #14 09-13-2011, 03:31 AM

I realise that this new problem is a real kick in the teeth.

I don't think you should be removing any more transmissions until you've done some investigative work on the one that is now fitted in the car.

[If the solenoid related advice above doesn't help]

If I were you (knowing what I know now) I would.

1) Drain transmission fluid

2) Remove valve body clean the outside with a little bit of brake cleaner and put it in a clean plastic bag.

3) Follow the procedure I've written for checking the adjustment of the brake bands in this post

722.118 Automatic transmission rebuild (Monster DIY)

You just need some compressed air to actuate the brake band pistons.

It is a simple process to do - though I guess a bit messy with dripping transmission fluid...

4) If you don't see any problems with the measurements and observations in step 3 then you should be able to get second gear...

because

...the clutches are only used for 3 and 4