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Old 08-30-2018, 01:54 AM
El Ted El Ted is offline
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Join Date: Jun 2014
Location: Ventura, CA
Posts: 9,303
Quote:
Originally Posted by sixto View Post
Vacuum control valve. As of a few years ago no longer available new.

Did this just happen or did you get the car this way?

The modulator is a controlled leak - should allow more vacuum to transmission with less pedal input, less vacuum with more pedal input. Harsh shifts suggest vacuum isn’t getting to the transmission or the transmission isn’t processing the signal. The modulator on the transmission at the other end of the vacuum line should hold vacuum and shouldn’t leak ATF. Make sure the rubber cap on the modulator is in place and not cracked. Break out the MityVac and gauge and get testing!

Sixto
98 E320s sedan and wagon
02 C320 wagon
Thanks for the reply. I found this thread:

http://www.peachparts.com/shopforum/diesel-discussion/356706-car-down-need-help-sourcing-vacuum-control-valve-vcv-84-300sd-w126.html

I have the car since 12 years. It's been shifting funky recently, but then was normal again. As of this morning, it wouldn't engage the first gear unless I was rolling, it would go in second gear.

My mechanic is doing the work. I have to talk with him in the morning, if he checked the modulator as well. It was late already, he may have only checked the VCV.
It seems, based on the thread, there is a good chance, the modulator is failing.
Are those available new?
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