C126 500SEC Gearbox Woes

[JonnyHahn]

Hi all
I have just completed a camshaft, and cam tower change on my 500SEC. It is the first time the car has fired up and moved under her own steam in maybe 2 to 3 years.
However in drive (the car has only been the length of the driveway) the car pulls itself but is very sluggish. I assume a sticking calliper may be part of the trouble. But when you go from Park to Reverse the car makes an absolute racket. I can only describe it as a thudding sound when you hold the brake on and the car shakes along with it. if you then allow the car to roll and apply the brake it then carries on. The sound is coming from the rear of the car though which makes me question if its the box?
Also i have noticed when coming out of Park the gearbox makes a big clunk. I'm sure before the car came off the road it didn't used to do it.
Thanks all

 

[alabbasi]

Have you checked of the vacuum hose from the intake to the vacuum modulator is connected? If not, it will slam itself through gears.

 

[JonnyHahn]

Have you checked of the vacuum hose from the intake to the vacuum modulator is connected? If not, it will slam itself through gears.

is that the red one at the back of the engine? connects to a red and black one?

 

[alabbasi]

is that the red one at the back of the engine? connects to a red and black one?

As a vacuum hose is a hose, I would not rely on color as people change them over time. If you get under the passenger side of the car (assuming RHD car). You'll see the black plastic modulator bolted to the side off the transmission with a vacuum line attached. Follow that line up (yes, it could very likely change color).