Volvo Forums - Volvo Enthusiasts Forum - compatible transmissions?

I have a 1981 264, but it has the B21F engine in it so I thought this would be the place to go. The tranny is starting to slip on it. It's my fault, I was doing burnouts with it. Any ways its an automatic and I don't know what tranny it has. My local junkyard doesnt have and automatic 240s so I was wondering if any of the 740 or 840 trannys are compatible with mine. Or if you think it might just need a new flywheel or clutch? It seems to shift fine when it shifts, it just doesnt shift automatically all the time, sometimes I can get it to when i start going in first then shift to second then drive, but sometimes it will stay in first or second up to 6000 rpm before i let off and fiddle with the shifter. So anyone that can help that would be great.