I have had numerous Getrags in my Opels and one ZF. The Getrag 240 definitely used a shortened 4-speed shaft with a 4-speed spline. An automatic spline is larger. The new shortened driveshaft length falls in between the stock 4-speed's and a stock automatic's.kwilford said:
I was under the understanding that the 240 output splines matched the Opel Automatic, which in turn was "standard" corporate GM. And since the automatic driveshaft was too long, it was just as easy to get your 4-speed driveshaft shortened with a GM tranny spline. And the input splines were the same as the stock Opel 1.9 CIH clutch disc, and hence the same as the GM S-10 clutch disc.