CX-60 Connection between engine and gearbox questions

[Carlh93]

The CX60 is described by the press as using an automatic clutch to transmit drive from the engine to the 8-speed gearbox. This is unusual - most auto boxes of this type are driven through a hydraulic torque converter.

Is any guidance available on my following questions about the above:-

1. If the car is stopped in D (Drive) without the handbrake applied, does it creep (on a level road) like a car fitted with a torque converter?

2. An automatic multiplate clutch does not tolerate slipping as a hydraulic torque converter does, and cannot multiply the engine torque ,so is the bottom gear ratio low enough to start the car, with a large load/towing a caravan, easily on a steep (up) hill without overheating/overstressing the clutch?


One of "Diesel Car"' magazine's journalists magazine states in the September 2023 issue, in the "Our Cars" reviews, that the CX60 has two cargo security nets: one to fit between the top of the rear seat backrest and the cant rails (just above the top of the window) PLUS a second net which is fitted from the floor to the roof. Two questions arise here:-

1. Is this correct? (I have looked at the handbook on line. It shows only a divider to fit above the top of the rear seat backrest. I have checked the accessories list, which does not seem to list a full-height divider)

2. If there is also a full-height divider, does the top of this fit into a second pair of fixing points in the cant rails which are forward of the point for the short divider? If not, where does it fit?

I'd very much appreciate guidance on the above. Thanks in anticipation!

 

[sinistriel@]

To answer your transmission questions. I don't have the CX-60 in my country so I assume it behaves the same as the CX-90 and does have creep function. For your second question about the clutch. The clutch set that is slipped during launch is the biggest in the trans and is designed to handle it and is located in the rear of the trans. One of the unique aspects is that it is a brake clutch vs a driving clutch and Mazda refers to it as the "B2" clutch as it is the second "braking clutch" inside the transmission. There are two other clutches engaged transmitting torque, the B2 slips and couples the output shaft to the intermediate shaft. The electric motor provides torque assist at launch that a torque converter would normally provide. I've circled the clutch set in question in this cutaway picture.

 

[Carlh93]

Many thanks!

Is the lowest forward ratio in the gearbox low enough for all eventualities, given that the connection between engine and gearbox is an auto clutch, not a torque converter, so there is no multiplication of the first gear ratio for a start demanding higher than normal torque

I had forgotten that the vehicle (CX90/CX60) uses Mild Hybrid Technology (MHT), so your response is interesting and helpful, as well as making an important point.

Auto clutch to separate/connect engine and transmission, not hydraulic torque converter

My interest was mainly in whether or not it drags enough to make the car creep when standing still on a level surface and with the box in D. You have confirmed that the car does creep under these conditions. This is because the multiplate automatic clutch runs in oil (in this case, the gearbox oil) and has very small clearances between its plates when it is disengaged. The oil causes friction, or drag, between the disengaged plates. But there should be less drag than with a hydraulic torque converter.

This behaviour occurs also with a DCT. though possibly to a lesser extent as the (similar-type) clutch which is not slipping when the car is at a standstill and in gear has to be free enough to allow the gear ratio to change in the other "side" of the box so as to be ready to operate after the car has started off. In both cases, creep in D can be avoided by using either braking system. But this must wear the clutch linings (due to the friction between them and the dragging oil) measurably less slowly than when the car is unbraked and allowed to creep.

Please forgive me for "preaching to the (hopefully) converted", but I need to mention the common, but undesirable, practice, of holding a creeping car with an auto or DCT box with the foot brake. Apart from wearing auto clutch linings faster than unbraked creep, it also risks dazzling a driver behind you at night because your car's powerful and brilliant brake lights are held on.

Solution all round is to slip the box into N and apply the parking brake, isn't it?

Similar problems occur with a manual box if the driver holds the (manual) clutch out of engagement, but does not depress the pedal far enough to hold the clutch plate fully clear of the flywheel face, and if the box is in a gear so as to be ready for starting off again, And particularly if the foot brake has been applied to stop the car rolling forward or back if the surface is not level.

Cargo Security

I'm still hoping for guidance on what it or isn't included with the CX60/available as an accessory and where it/they fit/s.

Please help me understand!

Some of you surely are caravanners?!