Any tips on vac modulator replacement 124 V8

[bobjohnston]

I'm getting ready to decide about replacing the vac modulator on my transmission. It has been shifting a little hard and late. I tried the adjustment before getting out the Mityvac. Guess what- it won't hold vaccuum. I even crawled under the car and tested it directly on the modulator with a fresh hose. Still pretty quick leak down.

Okay, the space on these V8 124's is pretty tight next to the transmission to get that modulator out. Has anybody out there done this (on a 400e, E420, 500E, or E520) and can tell me there is enough room to get it out without dropping the trans (I hope.) Any tricks to the adjustment after the install?

Thanks in advance.

[bobjohnston]

Finished this job the other day, so I thought I'd answer my own question for the archives.

This car has the newer modulator design with a white large cap. If the cap is fully twisted clockwise, (it can only turn about 1/2 turn due to an inner stop,) it can be gently pried off without breaking it, but the new kit does come with a new cap. The hardest part is getting at the two allen head bolts that hold the thing in with a plate. They were either 5 or 6 mm allen heads. I suggest feeling around up there to find them, one aft, one forward and slightly up from the modulator itself. Then use a simple allen wrench, and much patience as the bolts will only turn a little before repositioning the wrench. The front bolt can be loosened further with an allen driver bit on a flexible joint. Then, carefully pull the modulator straight out. Inside the trans will be a 2 inch long plastic pin that must be matched to the modulator if the part is updated. Then just reverse the whole process to reinstall, being careful to orient the parts correctly. I suggest adjusting the new mod to the same setting as the old one, then test drive to get it perfect, clockwise to firm up the shift, counter to soften it, turning it 1/2 to 3/4 turn at a time.

This smoothed out my shifts, I found out it was leaking vac using a mityvac tester.