My mom has an '03 Impala and the trans has started to slip during the last few weeks. I've searched and read numerous threads here about the PCS and other possibilities. The car has 90,000+ miles and we don't know if the fluid has ever been changed. So, which should I try first?

1) Unhook the neg battery cable overnight?
2) Have the codes checked?
3) Run Seafoam Trans Tuner thru it and change the filter and fluid to Dextron VI (and do not flush the trans)?
4) And on the fluid change, how much of the old fluid stays in the trans with just a pan drop?

Thanks
Mike

My mom has an '03 Impala and the trans has started to slip during the last few weeks. I've searched and read numerous threads here about the PCS and other possibilities. The car has 90,000+ miles and we don't know if the fluid has ever been changed. So, which should I try first?

1) Unhook the neg battery cable overnight?
2) Have the codes checked?
3) Run Seafoam Trans Tuner thru it and change the filter and fluid to Dextron VI (and do not flush the trans)?
4) And on the fluid change, how much of the old fluid stays in the trans with just a pan drop?

Thanks
Mike

OK sounds good till 3. Do not put Seafoam or anything else besides Dex VI in the transmission. For 4 I think about half of the fluid stays inside. Actually it is possible to flush the trans but you'd have to un hook the return line at the radiator. It's probably not worth the trouble.

About #3, I thought that I had read about some people running the Seafoam for a somewhat limited amount of miles before changing the fluid.
About #4, I've never changed the fluid in a automatic trans, would the flushing the return line be a standard procedure at a trans shop?

Thanks

I've heard of people pouring Seafoam in their gas, oil, down their intake, etc but I wouldn't do it. I think most Trans shops just drain the pan. The things is you don't want to have the transmission flushed like most shop do it. The only thing that should be flushed through the trans is clean ATF.

I've used seafoam in my gas before but have never added anything to a trans.
Thanks again.

We unhooked the battery overnight and it seems to have fixed the problem,
so far. I take it that when the PCS starts to act up, it's a signal to change the fluid?

No, its a signal to replace it.