Dear e r i c,

Good a.m. and may this find you well. If the crank sensor has not been changed, at 256K miles, it does not owe you a nickel. It likely is the source of the inconsistent tach readings. The wiring to the sensor deteriorates, leading to intermittent operation. Usually, that causes the engine to stop running. This is not a hard part to change on a B230F engine. I've never done this job on a B6304 engine. See the FAQs, under Features, above.

It is also possible that the tach's inconsistent operation is rooted in a loose or oxidized connector, in the circuit from the pick-up (on the differential) to the instrument. You'll need a wiring diagram to trace the circuit.

As to the tranny, have you had it flushed recently? Flushing, replaces all of the fluid - about 9 quarts - in the transmission. Draining the fluid in the pan - about 2 quarts - is not enough.

The trans fluid should be a bright pink. If it is brown, orange, black, etc., it needs to be changed. There is a procedure in the FAQs, that I think will work on an AW30/34. I've done the flush procedure on an AW71. It would be well to use fully synthetic fluid, if you plan to keep the car for yet a while. Otherwise, standard fluid will do.

Hope some of this helps.

Yours faithfully,

spook