1999 Pontiac Montana Hard shifting and shaking on takeoff

1999 PONTIAC MONTANA
130,000 MILES • 6 CYL • FWD • AUTOMATIC
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JONNYFRAG
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It's shifting hard getting to shift to 2nd (like slipping), but higher gears seem to work fine, highway seemed ok. But on takeoff it has now sometimes started really jerking and shaking. This is weird because it seems to happen more as the engine heats up. Works better cold with less hesistation going into 2nd when first started up and going. It seems like a similar problem I've had before and I took it to a tranny shop (expecting the worst) and they swapped a fuse in the engine compartment and it was all better. I hope it might be that fuse again, however a fuse is bad or it isnt, not intermittent or worse as it heats up. Anyone know what fuse they might have changed before (so I can change it..will m ake me feel better anyway) or something else to try and resolve this?

*edit* Since I forgot to put it already, yes the engine light is on, has been intermittently on for like a year. I am actually going to buy a reader so I can see what the codes are that it throws up all the time. Also the shifting problem is apparently a progressive thing, my wife says its been doing here and there some for a while now(thanks for telling me now when it's going all crazy on New Years Eve) but getting worse now, and again, develops when it heats up, not so much when it's cold.
Jan 1, 2009 at 11:46 AM
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BUDDYCRAIGG
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the tranny problems could be coming from what ever the check engine light is on for.

get the codes and we'll go from there.
Jan 1, 2009 at 7:39 PM
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JONNYFRAG
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The code is for a bad o2 sensor. I picked one up to change it. Don't know if that would do anything for this thing unless its throwing that code and not showing another (yet.) I did drive it around yesterday and try to get it warmed up but it didn't seem to do it and I also checked several of the fuses under the hood to see if any were bad and none seemed to be, although I didn't check them all.

Also, I called around today about having a trans fluid change and filter change...getting quoted ~$80. I know that things like this are likely to change depending on markets, but does that sound reasonable or high? I know a new filter (from Autozone) is about 27.00 but then there's the gaskets and all. The fluid level is fine and does not smell really burnt or anything, still nicely red and all.
Jan 2, 2009 at 9:23 AM
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BUDDYCRAIGG
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you saying that it works better when cold, and having an O2 sensor bad could be related.

so get that changed.

and $80 is kinda on the low end. i'm surprised.
Jan 2, 2009 at 8:22 PM