Subaru Repair: 2000 Outback tranny slippage, stall time, engine rev


Question
I thought you might think that.  Before I had a subaru I had a Plymoth Van from the early 90's, the transmission actually died in it while I was driving it.  So we replaced that then the next one began serious slippage about 10K miles into it and died at 18K.  Replaced that the third one had 34K and was beginning to slip when we decided enough was enough and bought our Subaru.  
Yes, we left it with the dealer for 3 days and they said it was normal. I still think it's not normal.  I'd almost call it a hesitation.  about 3 months ago we had to replace the fuel pump and filter cause they both died in it.  But still I wonder if it was the transmission and if there was some type of chip fix that makes it shift sooner than it currently does?
Thanks for the help. Heidi
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The text above is a follow-up to ...

-----Question-----
So I've noticed ever since we bought this Subaru almost 2 years ago that the Transmission seems to slip on occasion.  By slipping I mean it hangs when trying to switch gears sometimes or it hangs when you start from a dead stop.  By hang, that's a 1-3 second stall time during the time you give it gas, hear the engine rev but nothing happens then it goes, or you keep giving it gas and the engine revs and finally it changes gears.  It happens on hills and not on hills.  Now I've talked to some friends who own a 97 and they mentioned that they solved this very same issue with a firmware upgrade to the computer chip that controls the transmission.  Is this true, is there such a thing?  I've been searching the web all over and can't seem to find it.  If it's not true what would cause this?  This is an Automatic 2000 Outback stock base model, nothing fancy.
I did take it to the dealer when we first noticed it, they said nothing was wrong, they checked the transmission couldn't find a thing. So not sure what to make of all this but just hoping you can help or at least point me in the right direction.
Thanks, Heidi
-----Answer-----
We have seen some Subarus slip when shifted from reverse to drive - but only for a second or two - and this is normal. We have also seen some Subaru's slip when first put into drive after start up. Shift into reverse and it is always ok. If that is the problem, you need a low clutch piston and seal. The last one we did was almost $1600.00. As far as the slip when going up hills, if you fluid is good and the level is right, then you have problems. In case what you call a slip is not what I call a slip, a slip is when you press on the gas, then engine rpms go up, and the car doesn't move like it should. Subaru transmissions do sometimes fail. But, problems like you describe on hills are very uncommon. Also, if you have been having this same problem for two years, any chance it is not a problem and it is just something about the transmission that you are not used too? Finally, the computer thing. Not aware of any computer update that would fix your problem.

I would say that your best bet is to find the pattern to when the problem occurs, and then you drive it for the local dealer. Or, you can leave it with the dealer for a few days and let the service manager drive the car or let the tech take the car home. Also, check around, you may have a really good independent transmission shop you can trust. I would want one with experience with Subaru's, or I would not let them touch it. Good luck.  

Answer
Two things. Many dealers sometimes only look for what you say it is. An example: If you say the transmission is slipping, they look for a transmission slip - and don't notice the engine miss. Maybe you have a hesitation, and not a transmission slip. Is there another Subaru dealer you can try - a fresh look maybe? Or, can you get the problem to occur? If you could show the Subaru dealer, they should be able to diagnose your problem, or tell you exactly why it is doing the "normal" thing you don't like.