The #1 resource for our W116! Established 2004

Main Menu

Modulator valve isses?

Started by BCDC, 13 April 2022, 03:17 PM


Hi All, I'm wondering what to check for the correct operation of the transmission modulator valve. Where would I start to look for vacuum issues related to it's correct operation? My changes are fine under heavy acceleration but harsh at low revs just cruising along in town. Any ideas?


1978 280SE Cream with blue interior. With SLS


You will need to check the rubber connector hose for starters, likely it's old and brittle and I would just replace it as a matter of principle.  Just remember too that these Benz transmissions are supposed to shift quite firmly and crisp with no flaring, so not sure what you are comparing it to.  Granted it should not snap your neck off when shifting.  You can use the key under cap of the modulator to adjust the firmness of the shift,  clockwise is firmer and vice versa.
1977 450 SEL 6.9 - Astralsilber