Calling transmission gurus: 1980 300td with 722.1 won't go into 2nd - Page 5 - PeachParts Mercedes-Benz Forum

Zacharias · #61 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 · #62 09-12-2011, 11:57 PM

Could a sticking kickdown solenoid produce these symptoms?

Stretch · #63 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 · #64 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 · #65 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

rs899 · #66 09-13-2011, 06:40 AM

I suppose it's already broken so pressure flushing can't break it worse. Does the magic liquid somehow know that its supposed to deposit the crud in the machine rather than leave it in this or that part of the valve body or this or that solenoid? There is no substitute for taking things apart cleaning, and fixing what's broken. This isn't like working on a clogged toilet.....

Stretch · #67 09-13-2011, 08:23 AM

Quote:

Originally Posted by rs899

I suppose it's already broken so pressure flushing can't break it worse. Does the magic liquid somehow know that its supposed to deposit the crud in the machine rather than leave it in this or that part of the valve body or this or that solenoid? There is no substitute for taking things apart cleaning, and fixing what's broken. This isn't like working on a clogged toilet.....

Ahhh but when I get to the stage that Zacharias is at I bet I'll want to treat it like a clogged toilet - I bet he does too!

Zacharias · #68 09-13-2011, 08:38 AM

The solenoid issue is probably a red herring but I have to check.

The issue now is timing. I have basically run out of worktime for cars this fall as I have other commitments (house).

I have no problem with your suggestions Army but if I go that route it will be next spring. And I had planned to drive this car for the winter months.

Zacharias · #69 09-13-2011, 02:54 PM

Quote:

Originally Posted by Army

Ahhh but when I get to the stage that Zacharias is at I bet I'll want to treat it like a clogged toilet - I bet he does too!

You mean I can go at it with a plunger and some drain cleaner? Whyinthehelldidnchasayso in the first place

?

I got my sense of humour back today. Well sort of.

What is driving me bats here is that this transmission was perfect. No ifs or buts.

However now one thing bothers me. This 722.117 came out of a 240d. I put it into a 300td (non turbo). But I kept the torque convertor from the 240.

Honestly it never crossed my mind to swap TCs. Did I screw up on that....?