904 transmission, thrust Washer kit

Yep. Hit the nail right on the head Tracey.
Michel, You have thrust washers for the 4 pinion steel planetaries. Like Tracey says, you need the ones for aluminium gears.
I've just ordered a set from A&A. PN 12915A. Bit of a bummer really because you have to disassemble the trans before you can order stuff in order to get the right parts. Which leaves the trans in a million pieces for about 2 weeks while you wait for delivery.
Been there, done that.
Cheers. Gaz