for you guys that using GM syncromesh tranny oil , what is the oil weight that you guys using

 

There is no weight on it. However, GM does have different fluids, one for autos, one for trucks, one for passenger cars. You would want the latter. Transmission oil is normally 75-90w, which is equivalent to 10-30w engine oil. If they give you blank stares at the parts counter, say you have a z28 6sp and you want transmission fluid. I don't have the part # offhand but I will edit this post when I find it.