[mustanggt4650]

i have some stp automatic transmission fluid and it says for use in vehicles previously serviceable by dextron lll - mercon brands.

so will it work on a 1998 mustang gt with 4r70w automatic? cause i know it calls for 12 quarts of mercon v if your changing it, but i want to add a quart now instead of changing it all out and do it later when i have enough money.

also yesterday i put the last little bit of seafoam in a can into my gastank. will i have to change the oil now again or is that just when you put it into the oil crankcase / engine. the last time i put seafoam in the intake, crankcase and gas and me and dad changed the oil in it he noticed it smelled kind of like gas a little.

[mustang1010]

you cant use the stp in yours if it says for use with dexIII/mercon brands and you dont have to change your oil if you just put it in your gas tank; you have to change it when you put it in the crankcase. Hope this helps

[mustanggt4650]

yes that helped, but i also read the stp bottle after i posted and that helped also.

on the back it says: do not use this product in transmissions that specify ford type f, mercon - v fluids.

and recommended for use in electronically controlled automatic transmissions in 2005 and earlier.

suitable for use in vehicles requiring dexron ll , dexron lll, and mercon fluids.

[2oo5GT]

cool, glad you read that part. Definitley don't mix the stp with the mercon V. Mercon V is synthetic too.