> From: Tom Parker [mailto:parkert@ihug.co.nz]
> Sent: Thursday, September 16, 1999 8:50 PM
>
> Unfortunatly, the J type overdrive is completely drifferent,
> at least on the outside. There are three things you can
> take off, the solinoid, the pressure test plug and the sump
> plate.
There are also three plugs inside the sump which can provide further access
to some of the hydraulic innards. See your Bentley and/or Haynes manual for
further info,
> I haven't yet taken the solinoid off, as I lack the necessary
> thin spanner.
Easily done by getting the cheapest 1" wrench you can get and
grinding/filing it down until it fits. Does it click when you apply 12
volts? If so it's probably fine as these rarely fail. Perhaps you can borrow
a known working one from a local Volvo dealer since those cars used the
J-type as well.
> Diagnosis will require a pressure gauge.
Again, easily made, a number of references have already been provided for
this. I think it is worth the trouble to make the gauge and do a pressure
test to determine if you get any pressure or none whatsoever. Easier than
taking the trans out and then separating the two pieces.
> Having said this, we already know that it doesn't work. Can
> the hydrolics be fixed without dismantling the unit?
Not all the hydraulics. The pump (most likely cause of insufficient
pressure) can only be replaced with the OD separated from the trans
(implying removal from the car).
> Can the hydrolics be diagnosed with the unit taken apart?
If you can spin it, you can diagnose the hydraulics. So depending on your
ability to spin it out of the car, you may be able to diagnose the
hydraulics.
> What do you do to overhaul a *J* *Type* overdrive?
1. Replace all the o-rings. All o-rings except 2 can be replaced with the OD
in the car. The 2 which can't be are on the two pistons (see your manual
again).
2. Replace the pump and corresponding sleeve (easily ordered parts from a
Volvo dealer BTW). This must be done with the unit out of the car and
detached from the trans.
3. Clean out the filings. This can be done by removing the corresponding
plug revealed by the removed sump.
If you can't get any pressure, my bet is a faulty pump. Meaning taking the
OD out and apart. But it makes sense to try doing a hydraulic test first. If
possible, test the solenoid before doing the hydraulic test to confirm it
moves in and out as required. It is also possible to overhaul the solenoid,
but like I said, I think they rarely fail (at least according to local Volvo
sources where I live -- and there a heck of a lot more Volvos with ODs than
british cars -- J-type anyway -- so their sample set is got to be decent to
make such a claim).
Good luck.
Peter Zaborski CF58310UO
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