Ford Sierra Automatic Problem
John
Can anyone offer advice please?
I'm having problems with the automatic transmission on my Sierra. It's
become erratic in changing between the lower gears i.e. reluctant to change
up and overrevs, keen to change down and overrevs. Also difficulty in taking
up reverse although this seems to be OK when everything's cold.
Thanks,
John
Paul Mathers
I'll assume that you have a post 1985 Sierra with a 4 speed transmission,
please correct me if you have the earlier model with 3 speed trans.
I can't specifically account for the first part of your problem, there are
too many variables involved with the up/downshift process to be able to
speculate at this stage, suffice to say that on this model, vacuum modulator
failure is common and usually results in late shifting and sensitive
kickdown, get someone to check that out for you, it's an easy process and
consequently should be cheap. Delayed reverse engagement is usually
attributable to wear or shrinkage of the low/reverse servo seals, another
contributing factor could be damage to, or wear and tear of the direct
clutch (3rd. gear) which is also applied in reverse, a common failure in
higher mileage vehicles is the collapsing of the direct clutch thrust washer
and subsequent damage to the direct clutch support assembly. I'm sorry I
can't be more specific, auto transmission concerns can be tricky to diagnose
to a particular sub assembly without a full teardown, even when you have the
vehicle for testing.
Paul Mathers.
Transfix Transmission Services.
Tel/fax: 01226 381000
mr.f...@virginnet.co.uk
John <jo...@REMOVEhollywood96.freeserve.co.uk> wrote in message
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John
Many thanks for your response. I'm afraid I know very little about automatic
transmissions but the info you gave was useful. You're right, my sierra is
1991 with 4 speed. I've since had it checked by a local Ford dealer and they
suspect that two front clutches are worn and an epicyclic gear chain is
faulty. This probably means more to you than it does to me and I would
appreciate you're thoughts on whether this would be a reasonable diagnosis.
They've recommended replacement rather than repair - hefty bill I'm afraid.
Regards
John
"Paul Mathers" <pa...@transfix.freeserve.co.uk> wrote in message
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Paul Mathers
If your car has topped 100K, then I would always recommend replacement or a
full overhaul of the existing transmission, the diagnosis of the dealer in
regard to your specific concern sounds a little bogus, ie; the "front
clutch" in this transmission is only concerned with engine braking effect in
the lockdown ranges, ie; position 3,2 and 1 of the gearstick, so is hardly
relevant. if the epicyclic gearset was faulty, the effect would be almost
certainly catastrophic, ie; no movement or possibly driving in neutral, so
again, hardly relevant here. They're just trying to blind you with science
and sell you a new gearbox, which may be what you need anyway. before you
commit yourself to this though, please let me know what they intend to
charge you, I can probably supply you with a warranted replacement unit for
a fraction of the dealer price. Regards.
Paul Mathers.
Transfix Transmission Services.
Tel/fax: 01226 381000
mr.f...@virginnet.co.uk
John <jo...@REMOVEhollywood96.freeserve.co.uk> wrote in message
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