This was posted on a Honda Integra forum but reads true here too.
........" you do it for your motor oil...why can't you apply the same principles for you tranny oil for God's sake?!
1. for the street Honda calls for a 30 weight grade tranny oil...so look for the same rating in the synthetics.
2. CHANGE YOUR TRANNY OIL REGULARLY. Your tranny doesn't have a filter!!! what do you think gets jammed in your synchros if you try to extend the scheduling life of the oil?
3. GM Synchromesh HYPE: Enough already! it's just a tranny oil with friction modifier already blended in made to run at street temps. All the people who parrot how great it is have no clue about it's operating temp range. Run synchromesh on a hot day at an Track day lapping session and you'll see opinions posted like "I thought synchromesh was good? Now I'm grinding after my day at the track."...DUH!!... no kidding.
4. Redline MTF is 30 weight, Redline MTL90 is 40 weight. If you have the former you don't need to change it for the winter in the snow. If you have MTL90 then you have to drain for the winter. Would you run a 40 weight motor oil in your engine when the ambient temp drops below the freezing point?
5. if it's too slippery for your operating temp, add a cap or 2 of friction modifier.
Know your intended use and the temps you operate at.
the selection of the right oil and why you are having problems isn't rocket science guys...it's because you are choosing the wrong oil for the job you are doing and all it takes is reading the label and knowing what the label means and your operating temp range."......
Hope this helps
Bill.