92 Legacy Auto Transmission Problem

[beckery1]

I have a 92 Legacy Automatic, Front Wheel Drive and with only 91,000 miles on it, is up to its third tranny. Each trans I've had installed has had the same problem. The shift from second to third is not crisp, it kind of hangs for a second or two and then goes into third and sometimes it doesn't feel like its going in all the way. I just had a new trans put in after the last one stopped working completely. It has this same shift problem between second and third. Otherwise the trans works perfectly. Since all the trannys I've put in this car have had the same problem, I'm wondering if maybe there's something external to the trans that could be causing this problem. I'm afraid that if I don't correct it, this trans will also fail. Any insight into this would be greatly appreciated.

Thanks

[shortlid]

How offten do you change the ATF, the filter and pan gasket?