W123 Shifting Problem

W123 Shifting Problem - Vacuum...

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Darrell with DieselBenz.info - 09 Feb 2006 02:59 GMT

Cheers all,

1982' W123 D

Well it has happened to me. Driving around and all of the sudden, it
will not shift into DRIVE, so I'm stuck in L or H or whatever 2nd is :)
I had to stop and put it into park, and now it seems to do it all the
time. When I was on the freeway today, I was in D and I pressed on the
throttle, and the engine revved up, but didn't go faster, it was kinda
scary. Is this a preview of upcoming attractions, like total
transmission failure? Anyways

My friendly neighbor says he had the same problem, and he drove right to
the shop, they spend $40 and he was out of there in 20 minutes.

As you may know I am not an expert, can someone explain what I need to
do, and what exactly part I need? From sniffing around the old
newsgroups, do I need a "123 Turbo Diesel Transmission Vacuum Shift Valve" ?

It sounds like that's what I need. If someone can give me some good
advice, I will do it and add it as one of my guides, as always.

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thanks,
Darrell

http://www.dieselbenz.info/

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Richard Sexton - 09 Feb 2006 04:29 GMT

>Cheers all,
>
[quoted text clipped - 14 lines]
>do, and what exactly part I need? From sniffing around the old
>newsgroups, do I need a "123 Turbo Diesel Transmission Vacuum Shift Valve" ?

That just modulates the shift does it not ? I'd like to say it's a B2
piston failure which is no $40 repair (but it's not a $4000 repair either)
but if that were true it wuld work in higher gears but you'd have a bugger
of a time getting the car to move from stop but once into 3rd you'd never
know anything was wrong with it.

I don't understand what "driving around all of a sudden it won't shift
into D" means. You were driving but the trannsy wasn't in D? How does that
work?

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Darrell with DieselBenz.info - 09 Feb 2006 04:42 GMT

oh yeah, so the shifter is physical always in D, but sometimes the car
will only upshift to the middle gear (2nd/S?) L-S-D it's definatly in
the second aka middle gear. If I shift into N and then back into D,
then it will uusually go from 2 to D in about 1 second. The rest of my
vacuum is pretty good. Plugged all the leaking locks, replaced ignition
shutoff valve and injection shutoff valve. shuts off quick.

>
>
[quoted text clipped - 29 lines]
>
>

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thanks,
Darrell

http://www.dieselbenz.info/

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Richard Sexton - 09 Feb 2006 05:42 GMT

>oh yeah, so the shifter is physical always in D, but sometimes the car
>will only upshift to the middle gear (2nd/S?) L-S-D it's definatly in
>the second aka middle gear. If I shift into N and then back into D,
>then it will uusually go from 2 to D in about 1 second. The rest of my
>vacuum is pretty good. Plugged all the leaking locks, replaced ignition
>shutoff valve and injection shutoff valve. shuts off quick.

It's not a vacuum problem, that just affects the harshness or softness of the
shifts. You can pull the vacuum off altogether and it'll work just fine, it'll
just be quite harsh at low speeds.

Neutral to first is slow but sometimes happens, ok gotcha.

What about 1-2, what about 2-3 what about 3-4?

How is reverse? Any quicker?

When did you last replace the fluid and filter on the transmission?

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Darrell with DieselBenz.info - 09 Feb 2006 14:44 GMT

I have noticed recently that the time from Park - Reverse does take a
second longer than usual.

From a standstill it shifts from Park to first fine

P-1, 1-2, 2-3 just like normal. 3-4 is where my problems lie.

It IS freezing here in Utah, but when it warms up (45 degrees F - 7 C)
it seems to have no affect.

About a year ago I did replace the filter and fluid. Maybe I should st
least start there and do that -eh?

D

>
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[quoted text clipped - 19 lines]
>
>

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thanks,
Darrell

http://www.dieselbenz.info/

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Mitchell Knight - 09 Feb 2006 15:38 GMT

I scuttled and sold my 240D when it did this. Except I was stuck in
reverse!

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Richard Sexton - 09 Feb 2006 18:45 GMT

Here's what the guy that works on my cair said:

>> I have noticed recently that the time from Park - Reverse does take a
>> second longer than usual.

Classic symptom indicating imminent failure (possibly way in the
future). They're destined to fail in the same way we're destined to die.

>> From a standstill it shifts from Park to first fine
>>
>> P-1, 1-2, 2-3 just like normal. 3-4 is where my problems lie.

Clarify please. Are you pulling it all the way down to the L ,aka 2
position?

>> It IS freezing here in Utah, but when it warms up (45 degrees F - 7 C)
>> it seems to have no affect.

More clarification needed here too. Are you saying the temp has no
effect or the problem has no effect?

The classic symptom of impending doom can be more pronounced when cold
especially with played out dino based ATF. Amsoil synthetic fluid makes
a big difference. When used in PS systems you can actually feel the
reduced steering effort. This also holds true in warm weather.

>> About a year ago I did replace the filter and fluid. Maybe I should st
>> least start there and do that -eh?

You betcha!! Do the synthetic thing, if it turns out that the trans is
in need of overhaul you can drain and save the pricey fluid for future
use or in another vehicle. Amsoil ATF can go 100,000 miles 60,000 under
severe operating conditions.

> I'l guess though and say it's related to the K1 spring. There are
> K1 spring rebuild kits around on ebay with heavier duty springs.

K1 & K2, Ive recently seen valve body kits (aka shift kit) with these
items in it. if needed I may be able to find the web site.

> It is replaceble on a 126 without pulling the tranny, but I think it's
> a bit of a squeeze on a 123.

Easy on either.

> Duno if that's it though, lemme ask around.

Could just be too much vacuum or modulator adjustment too. If the
vacuum is disconnected from the modulator it should snap your neck when
it shifts. This being the case, the tranny ain't dead yet.

> I seem to recall also that if it takes 2-3 seconds to shift into
> reverse it's new tranny time - but don't take that as authoritative.

An indicator of wear, yes gospel, no.

JB

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Darrell with DieselBenz.info - 09 Feb 2006 20:00 GMT

> Clarify please. Are you pulling it all the way down to the L ,aka 2
>position?
>
>

I go from Park to Drive, then I can just feel it shifting from 1-2-3
then it just likes to stay at three. but then again, this morning it
was hesitant, but it did go right into drive at the appropriate time.

> More clarification needed here too. Are you saying the temp has no
>effect or the problem has no effect?
>

Well, it's cold here always, but it does seem that after the CAR has
warmed up, it will slip more so. This morning it was fine. The only two
other times it was really bad, was when the car had warmed up to normal
operating temperature.

I will definatley get myself some synthetic Amsoil ATF.

I see online everywhere "AT Rebuild kits" for my car's tranny. (W4A 040
Overhaul kit, 722.3)

Does anyone have any experience with this? I an just some nerd, but I am
willing to learn. Of course, I'd like to "try" all the cheap and easy
stuff first. Transmission Vacuum Valve? But I will do what I have to
do. I think it's actually been "slipping" for years, it would be nice to
get a nice new tranny.

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thanks,
Darrell

http://www.dieselbenz.info/

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Richard Sexton - 09 Feb 2006 23:10 GMT

>Transmission Vacuum Valve?

You can test this by disconecting the vacuum to the transmission. It's (usually,
unless it's been dicked with) a black line going downbehind the back of the
engine. Unplug it from the source.

Disconnected, shifts will be slam-you-back hard. [1]

If your tranny works normally now, then it is the then it is indeed the
VCV - vacuum control valve. If not, plug it back in and if changing the
fluid and filter doesn't fix it, well, um, Houston we have a problem.

It's not the B2 piston, another common fault, that controls N-1, 1-2
shifts only.

I would try replacing the K1, K2 springs, that MIGHT be it, but dammit
Jim I'm a computer programmer not a transmission doctor.

[1] but the trans lieks this and will last longer. I disconnect mine
on priciple andhave > 400K mi on my original tranny (with a B2 upgrade
at 350K mi when it broke)

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Richard Sexton - 09 Feb 2006 16:41 GMT

>I have noticed recently that the time from Park - Reverse does take a
>second longer than usual.
[quoted text clipped - 8 lines]
>About a year ago I did replace the filter and fluid. Maybe I should st
>least start there and do that -eh?

Ayup.

Well, I can't say based on the symptoms that it macthes any of the
easy filure modes I know about.

I'l guess though and say it's related to the K1 spring. There are
K1 spring rebuild kits around on ebay with heavier duty springs.

It is replaceble on a 126 without pulling the tranny, but I think it's
a bit of a squeeze on a 123.

Duno if that's it though, lemme ask around.

I seem to recall also that if it takes 2-3 seconds to shift into
reverse it's new tranny time - but don't take that as authoritative.

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