'98 Volvo V70 transmission slip


My V70 (non-turbo, AT) with roughly 171k on the odometer is starting to slip. When cold, the transmission’s solid, but as she heats up, the slippage gets worse, to the point where it’s very difficult to drive.

Slipping only occurs in low gear, but there is noticeable performance deficiency in high gears, as if there are intermittent slippings happening then. The Engine seems to be suffering, too, as I am sometimes getting misfires on 1 and 4, with error codes PO301, PO304, and PO300.

I have changed the fluid a number of times, though never flushed. The first time, about a month ago, i added LucasOil’s transmission additive, which helped for about a week. Then I replaced the fluid without Lucas, which had bad results pretty quickly. I’ve done the fluid again, adding Lucas, but have been avoiding driving it.

My mechanic wants 2000 for a used transmission installed, 3600 for a new transmission installed. AAMCO estimates 2500 to rebuild her, or about 1100 if I bring the transmission to them for a bench-rebuild. OR, I can get a used one from the local junkyard for $80. I’d hate to use a used transmission, but I just can’t afford most of my options.

Any suggestions or ideas about what might be the problem?