Dear euphonium_john,

Good p.m. and may this find you well. I can't recall a post relating to 900 series cars, in which differential failure was reported. Absent collision or road hazard damage, these things seem not to break.

More likely, the transmission has packed it in. While the Aisin-Warner trannies are quite durable, failure of the automatic transmssion fluid (ATF) cooler - built-into the radiator - allows coolant to get into the tranny. The water dissolves the glue, that adheres the clutch pack facings. Clutch material fibers clog fine fluidways, wrecking the tranny.

What color is the oil on the underbody? If it light-weight and reddish, that is transmission fluid. If it treacly and dark, that likely is gear oil from the diff.

If oil is on the underbody rearward of the front seats, that suggests a transmission issue. If the oil is only in the area under - but not forward of - the boot (trunk), that points to differential failure.

If the transmission is history, do not get it re-built. This is a huge waste of ££££s. You can get a replacement from a salvage yard, for small money. The trans fluid should be a clear, rosy red. Any other color - brown, orange, black, etc., etc. - means trouble. Once you get the replacement put in, flush it with new fluid and drive 1,000 miles. Re-flush the tranny with Mobil 1 transmission fluid, and you should be rolling smoothly.

Hope some of this helps. Please post your further findings.

Yours faithfully,

spook