CVV fixed Transmission

[s535is]

Finally got around to changing the CVV on my 540 and can happily report it fixed the problem with downshifting. For quite some time the car would not downshift properly and it appeared to be temperature related. It was very annoying having to get into the floor switch all the time because this caused a downshift of two gears when I only wanted one. As best as I can tell, the CVV diaphragm was bad causing enough of a vacuum leak to screw up the "load" signal to the ECU. Worse when warm.

For anyone else with downshift problems, try the CVV before expensive transmission work. BTW, the CVV on 540's is a giant pain to work on, be prepared to die grind the screw heads off.

1998 540ia

[BigRickMc50]

I'm sure that JimLev will deliver the specifics of bolt diameter and length, but I know that he always recommends to anyone doing a CVV repair that they replace the factory's Torx bolts with hex head bolts for ease of removal in the future.

Owning two I6's, I've never had the need to note the particulars.

[JimLev]

the CCV can easily be removed with the intake manifold in place in less than 1 hour. A 1/4" ratchet, a short extension, and 10mm socket is all you will need to remove it.
6mm x 1.0 x 25 mm hex bolts.