Hi All,

The last couple of times I've started my car with a warm engine there's been clouds of smoke which goes away after 5 minutes or so, starting cold is fine. Doing a search here suggested a number of reasons and I'm going through trying to eliminate the easiest ones first. I climbed underneath to find the Vacuum Modulator on the transmission as my first item on the list but could find anything like it. I found the banjo fitting for the oil cooler pipes and the dipstick but no sign of a vaccum line from the manifold.
It's a '73 450SLC, does anyone have a diagram of these 3 speeds with the VM location shown or a clue which side to started searching ?
I just have the car on a jack/stands so access isnt ideal.

Thanks for any help,
Gary

On the 4 speed autos, the modulator is on the RH side of the trans, about halfway back, just above the pan.

If I were in your position, I would follow the vacuum line from the manifold back to the modulator......

If you suspect the modulator, then you will be experiencing a mysterious loss of trans fluid..... You can just remove the vacuum line from the intake manifold to test the modulator theory. Cap the manifold to ensure you do not run the engine lean.

Jim

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Thanks Jim, I did try to locate the connection to the manifold unfortunately with RH drive versions there are rigid power steering pipes running behind the engine which make it almost impossible to see or feel behind the manifold. The P/S pump is still on the left but the P/S box is moved to the right so extra plumbing required !
I did find a square metal plate close to where you suggest but it had no pipes leading from it. I'll try and get under again at the weekend to find it.

Why not check the vacuum line that connects to the intake from the modulator? Pull the end out and check inside, if there is any oil resedue then you diaphram is bad inside the modulator. Also, if that is the case you might be able t just change the rubber diaphram and not the whole modulator.