Okay, right from the get go, here's the basics.

I have an OM617 and 722.3 (i believe it's the 722.3? 4-Speed) from an '83 or '84 300D transplanted into my '92 Dodge Dakota with an All Wheel Drive conversion. She's been running perfectly for almost 2 years.

This problem popped up, with no warning. I literally drove the truck to the store to get snacks, and when I drove home, it would no longer downshift by itself based on throttle position. At the same time it developed a Rapid Upshift problem where it will shift through all of the gears and it's in 4th before it even hits 15mph

It starts out in 1st gear, rapidly upshifts, and then refuses to downshift no matter how much you mash the throttle. It will downshift to 1st (by itself) if I come to a complete stop, or I can manually downshift it.

My first thought, was that the Kickdown / Bowden Cable had snapped, but it's intact and functioning (even tried adjusting it, thinking maybe it stretched some). Fluid level is correct and the fluid is clean. Transmission isn't slipping either and it averages 165 degrees fully warmed up and driving (I have a Trans Temp Gauge installed in the truck)

I'm kind of lost here, considering that whatever happened, happened without warning.

Maybe the bowden cable came loose inside the transmission or broke in the sheath? The behavior you state sounds like the bowden cable is not functional.

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Current stable:
1995 E320 157K (Nancy)
1983 500SL 125K (SLoL)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Gone and wanting to forget:
1985 524TD 167K (TotalDumpster™) [Definitely NOT a Benz]

That was my first thought too. However it does have tension on it when pulled, and springs back when released. Unless something broke inside the valve body. I'll have to pull the pan to check that.

Just to update, I dropped the pan before work this morning. The Bowden Cable isn’t broken, though I didn’t really have much time to look further. I’ll do some more searching after work.

The rapid/stacked upshifting sounds like a modulator with no vacuum to it or a failed modulator.

Good luck and please post the solution.

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"Rudeness is a weak man's imitation of strength" - Eric Hoffer

74D:

The point at which shifts occur is a function of two opposing hydraulic forces: control pressure/throttle pressure vs. governor pressure.
Early and/or stacked shifts occur when either the throttle pressure is low (broken or slack cable), or the governor pressure is high.
If the throttle pressure cable is intact, look to the possibility of a stuck governor centrifugal valve. If the governor valve is wide open, the high pressure will be seen by the valve body as high road speed, and promptly upshift, and upshift, and upshift.

Pulled the governor out last night, it’s moving freely. While I was under the truck I also replaced the plastic vacuum line to the modulator, since I was right there and the original had a kink in it.

Did a filter and fluid change (even though I just did that 700 miles ago)

Still won’t downshift, and still has the rapid 1-2-3-4 upshift.

Guess it’s time to dismantle the valve body and take a look inside it

Subscribed, I can't wait to learn what's going on here .

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-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

Never did find the cause of the problem. Been manually shifting it.

I’m just going to use this as an excuse to install a NP435 4 Speed Manual Transmission in the truck. Gonna have to step up to some 35-38” tires though (from the 32” tires) to help offset that massively steep 6.69:1 ratio 1st Gear and 8.90:1 ratio Reverse

I wish I had it saved but I've seen a video of someone cracking up while someone steps on a stool to get into a lifted truck and then pulls the stool up with a rope.

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CC: NSA

All things are burning, know this and be released.

82 Benz 240 D, Kuan Yin
12 Ford Escape 4wd

You're four times

It's hard to

more likely to

concentrate on

have an accident

two things

when you're on

at the same time.

a cell phone.

www.kiva.org It's not like there's anything wrong with feeling good, is there?

That must have been obnoxiously tall.

Even when I had 44” tires on my Dodge D50 I just grabbed the steering wheel and seat to pull myself up into the truck

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'92 Dakota : OM617 Swap
'73 Duster : 8-71 Blown 426