I've got a 94 Civic DX 4-door with a manual transmission. I'm going to change the transmission fluid and my Haynes manual call for 10W-30 weight standard engine oil. It seem a little light weight (my pickup uses 90 weight) and I'm wondering if my crap Haynes manual is wrong.

What weight oil is correct for a 94 Civic DX manual tansmission?

Thanks for your help!

The owner's manual calls for 10W-30 or 10W-40 engine oil (SF or SG). The problem is that newer engine oils are not allowed to have ZDDP in them anymore. ZDDP was an antiwear additive that helped these oils to be used in manual transaxles. Newer engine oils can negatively affect the bronze in the synchros. Therefore, I only use Amsoil 5W-30 Synthetic Manual Synchromesh Transmission Fluid (MTF) in my 1993 Civic DX manual transmission. It improves shifting quality and gives improved gas mileage over the Valvoline SynPower 10W-30 I previously used, which was still very good. I plan on changing it every 30,000 miles.