transmission modulator - PeachParts Mercedes-Benz Forum

jimm1009 · #1 03-27-2013, 09:01 PM

I have a '91 420SEL with a green transmission modulator valve.
I have not removed it but I have cleaned it very well and can find no part number.
I ordered one through EPC for my VIN and it is black (126 270 91 79).
On the Mercedes-Source web site they mention that this black unit is an improved part over the older original unit.
What I am concerned about is that they are usually color coded for a very good reason and of course I am no longer green if I use this one and frankly don't know enough to know what is correct.
I know how to remove it but can not find the reference for setting up the new unit whether I acquire another green one or use this new black one.
According to the data card I have a 722.355 automatic but I do not find a number on my tranny to verify this.
I am the 3rd owner so there is no solid way to know if this is the original tranny or not.
jimm1009 here or jimm1009@yahoo.com
E-mail would probably be better as I am relatively new to this forum.

Dr. Sternschnuppe · #2 03-28-2013, 07:42 AM

Write me, please, the VIN of your 420 SEL.
I'll going to help you...

Gilly · #3 03-28-2013, 08:16 AM

I think they are just color coded to aid at the factory, the modulator may have been tailored to a specific engine/chassis combination. As far as changing the color to black and saying it is an improved unit, many times manufacturers make changes after the car is built and will do things like this after the production run, MB is especially known for improving things long after a car is out of production. The changing colors helps ID what you have. If yours is green and the new one is black I'd assume you are getting the updated part. Very possibly this is your only new part option, you coud try to find a green one used somewhere, but is shooting yourself in the foot in my opinion.
I can't tell you if the black one is still tailor made for your engine and chassis combination, but would be willing to say it is. You could try looking up the modulator for other engine/chassis combos that ran a 722.3 of similar vintage and see if it is the same pn.
Once in awhile I would need to adjust the modulator after instaling a new one, I think they must have a quick test they run for adjusting it and usually felt fine, if you shift quality sucks (too hard or soft)you can adjust it if you need to very easily.