Date registered: Dec 2005
Vehicle: W211 E320 Bluetec R129 SL500 - $1300 car ........ Ford F350 6l
Location: CA Bay Area
Mentioned: 9 Post(s)
Quoted: 1122 Post(s)
There is a latch that goes between transmission gear teeth. The design could wary, but the idea is to give it basic lock, not design for extreme situation.
DON'T try apply while the car is still moving.
It is common in the city that inexperienced drivers apply transmission brake, than the parking brake. By the time wheel brakes catch, the weigh of the car on steep slope leans on the transmission latch. That makes lot of fun when the driver tries to disengage the brake later.
Other thing that actually made topic in W210 section - the transmission brake holds the drive-shaft. You lift one drive wheel and the other spins freely via the differential.
So do use parking brake and whenever in doubts - better overuse it than underuse.