"Steve" <no@[EMAIL PROTECTED]
> wrote in message
news:n5-dnThudIjlwpfanZ2dnUVZ_smnnZ2d@[EMAIL PROTECTED]
> Julian wrote:
>
>> The gearbox is an A727 behind a 440 motor in a 1973 Jensen Interceptor.
>>
>> My box has developed an annoying problem. When the box is cold I can't
>> get any forward gears although reverse works perfectly. If I hold it on
>> the brakes and give it a few revs in reverse for a minute to warm the
oil
>> up it suddenly starts working normally, whereupon it then works
perfectly
>> for the rest of the day.
>>
>> The fluid is new, (and clean) the filter is new and the oil level is
OK.
>> When the gearbox is working normally it behaves perfectly without a
hint
>> of any problem.
>>
>> I've studied the schematic and 'elements in use table' in the Chrysler
>> workshop manual and have decided that the problem must be connected
with
>> the rear clutch, probably sticking. I can't see any problems with the
>> valve block, because in drive and stationary, oil is ****ted straight
>> through the manual valve (which can't stick because it connected to the
>> selector lever) through to the rear clutch. Oil pressure must be fine
>> because it drops into reverse perfectly.
>>
>> Would anyone care to comment on my diagnosis, is there anything that
can
>> be done without removing the box and has anyone rebuilt the gearbox
>> themselves?
>>
>> Thanks Julian.
>
>
>
> How old is the unit since last overhaul? I have the same transmission in
> several vehicles, and the only time I experienced the same problem was
> when my 1966 727 was about 35 years old and had not yet been overhauled.
> The colder the weather, the longer it would take to decide to engage in
a
> forward gear, and I even got into the habit of dropping it into reverse
> and gently revving the engine against locked brakes in order to heat the
> fluid more quickly. Once it finally dropped into gear, it would work
> flawlessly all day long.
>
> Cut to the chase- I finally opened it up and found that the piston lip
> seals on the rear (direct) clutch were as hard and brittle as un-cooked
> pasta. Once heated above room temp, they would soften and seal to the
> cylinder, but when cold enough fluid bled past to prevent the direct
> clutch from engaging.
>
> The problem can be aggravated by other internal hydraulic leaks in that
> transmission as it ages so that the pump output just isn't sufficient to
> overcome the clutch leakage. A common spot that you have to watch is the
> thrust washer between the input and output shafts- make sure you set the
> end-play (and therefore the fluid loss at that junction) correctly on
> rebuild.
>
> Good luck!
>
> -Steve
Steve (and all the others) thanks very much. I think you've hit the nail
on
the head - the car has done about 70,000 miles, was built in 1973 and I
don't think the box has ever been worked on.
I've spoken to a gearbox specialist (in Crewe, England) who is a 727
whizzkid and does most of out Mopar drag transmissions and he said the
same
as you - it's the piston seal for the rear clutch that have hardened up.
Anyway, he's going to do the work on the gearbox (after I've dropped it)
and
also fit a ****ft improver kit. Jensen specified the softest ****fting
option,
and the change from 2 to 3 is just so slow that it almost binds up on
itself.
I think I've sourced a 440 block today that I want to build up over the
winter with a stroker kit. (prolly 500cid) I'm formulating the plan as I
read Chuck Sentore's book 'Big Block Mopar Performance.'
I've found Mancini, 440 source and Summit for components on the internet.
Are there any other good suppliers that will ****p to the UK that I should
be
considering?
Thanks Julian.
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