W123 Shifting Problem - Vacuum...

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?

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.

Richard Sext>>

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?

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

Richard Sext>>

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

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.

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

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

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.

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.

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.

Easy on either.

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.

An indicator of wear, yes gospel, no.

JB

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.

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.

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)