ChrisGamlin
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| posted on 7/6/07 at 08:04 PM |
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OT - Rover MGF Steptronic gearbox woes
Dont suppose anyone knows anything about this gearbox do they? A friend of mine has one of these in an MGF and from what I understand its a CVT type
gearbox with 6 "gears" rather than a conventional auto.
The problem she has is that the gearbox has developed a fault whereby when cruising or especially when slowing down, the gearbox changes down far too
quickly straight into first, giving massive engine braking and almost bringing the car to an emergency stop!
Even if manually selecting the gears when not in "Drive" it also does the same I think.
From a little digging via google it seems the CVT is controlled by a hydraulic pump that pushes two cones together, thus changing the diameter of
where the drive belt sits on these cones so changing gearing. It also seems to have an output speed sensor somewhere that was mentioned to be related
to gear selection but I couldnt find any more info on this, but I suspect its possibly one of these two components (or parts related to the control of
these) that are at fault.
Does anyone know if there's any diagnostic tools (similar to VAG COM that Ive used on VW/Seats etc) that might help, or whether there's
any commonly known issues with these boxes that we could check?
cheers
Chris
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ScotJebus
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| posted on 7/6/07 at 10:06 PM |
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it its a CVT type auto then its just the same idea as a scooter transmisson, have you looked at the condition of the belt and cones maybe they are
damaged? didnt think they used this kinda of transmission on cars as they cant take a lot of power, must of been mistaken on that one
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MikeRJ
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| posted on 8/6/07 at 07:45 AM |
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The ZF CVT gearbox fitted to the MGF/TF are actually very reliable mechanicaly. The faults almost always seem to be sensor related. Does your friend
get the amber gearbox fault light illuminating?
There is an excellent description of the operation and various faults and limp home strategies on the
MG-Rover.org forums.
Unfortunately you need the Rover "Test Book" sysem to read the fault codes, there are no low cost solutions such as VAG COM that I know
of.
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ChrisGamlin
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| posted on 8/6/07 at 12:54 PM |
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Cheers Mike, interesting link. Ive not yet had a look at the car and it only intermittently has the symptoms described, but having read through that
link I'll ask a few more questions.
I think being likely electrical its going to be something that a Rover specialist is likely to diagnose far quicker than me or even a general garage
will be able to.
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