i have a question about cvt's

[Clan]

There were quite a few transmission control problems developing with the CVT just after the end of production in about 1992 .
By now ...16 years later i would say ALL CVT transmissions have some kind of control fault with the gear ratio not going up to "top" gear ,causing excessive noise and really bad fuel consumption .

Problems can be:
Throttle kickdown switch on the end of the accelerator cable .

Brake switch high resistance on the master cylinder .

4 way vacuum control valve rubber valve heads broken off inside ( easy repair )

Tachometric relay problems ( Under the Brake master cylinder , it gets hot there )

Vacuum leak from the main pipes to the rear due to welding around the transmission cooling air duct along the length of the car ( L/H side ) Pipes melted !

Vacuum leaks from the rotating seals where the two pipes go into the Primary unit drum .

Vacuum leaks through a broken Primary unit diaphragm one side or the other ..

Broken diaphragm springs in the secondary unit jamming the pulley

Failing all those , the Main nut falling off the end of the secondary unit drums !

Other less serious faults with the clutch disengage device , causing a grating when selecting gear , the microswitch or wires broken on the gear lever .

The clutch clearance is sure to be far too hiigh , no one knows it is adjustable with shims , let alone how to adjust it ..


When a CVT is working as it was designed to when new ,it is a great innovation , I remember some time in the 1980's setting off from the severn bridge toll booths at the same time as a Vauxhall Cavalier 1800 injection and we were identical neck and neck up to 80 mph , then he started to ease ahead and pull away with his much greater bhp . Every time he changed gear you could see him drop back about 4 or 5 feet . whilst the B14 had a constant surge of acceleration . Frank Williams even tried a Formula one car with this transmission . Volvo still hold the rights to it ..