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 ..

[scooters]

Is the CVT system on the 66/340 more sophisticated than the earlier variomatic system on the Daf 33,44and 55? My 44 is nearly 40 years old and the variomatic system is the most reliable thing about it! Every now and then you need to cobble a bit together but it doesn't seem to dempnstrate the problems above.

[foggyjames]

Well I'm really not a CVT expert...but...I believe the short answer is yes, they are more complex.

I think it would do the 300 series section a power of good to team up with the DAF guys more...after all, they ALL must face these various problems...whereas it's a tiny minority of the Volvo scene.

My initial suggestion is to consider getting help from the DAF owners club if we're running out of answers. That sounds a bit pathetic, but they're thoroughly nice people, and they know a damn sight more about variomatics than I do! I very much appriciate the contributions from our resident CVT experts...so my references here are a slur on my own knowledge, and no-one else's!

cheers

James

[spike4073]

right ...sorted the problem......soz havent posted 4 a while... internet been off.....a mate of a mate who seems familiar wiv these systems had a look and now its sorted....must confess that im not entirely sure what he did ....he just seemed to mess around with the carb and then it was fine......guessin it wasnt set up right......

on the subject of carbs...does anyone here know what if any other carbs are a direct swap for the one on a 340 dl?....or even what type the origonal is?

[Clan]

He probably adjusted the micro switch if it was a very early 343 before the tachometric relay came in about 1980 .
The carb is a weber 32 DIR but there are many versions suffixed with numbers such as 96 or 100 etc depending on what attatchments they have .., renaults use them too .

[harpulina]

Hiya I see my posting of a week ago has gone kaput so here goes again.
If all else fails with achieving high gear follow this,
Take innards out of high range solenoid, put a wad of blue-tac in place to block hole in plastic , replace.
Intercept vac tube as it leaves the 4way with t junction lead another tube thru firewall to alongside console put a tap (aquarium) on end and fix to console side.
Open tap is medium range, closed tap is the elusive high range, Just make sure your in Medium when you pull up or clutch will slip on starting again.
use at will, evan in town, whenever you have a strech worth changing on,
High range solenoid is engine side, you wont regret. cheers Chas