Tranny and diff oil...

which brand do you guys use? my car's manual calls for gl-5 oil.

I was wanting to get redline 75w90ns gl5 oil for the tranny and redline 75w90 gear oil for the rear diff, but the stuff is so damn expensive!

Expensive, but worth it...

Red Line is my favorite, but I've also got some AMSOIL and Royal Purple in play in various vehicles.

robert

I use Redline MTL in the transmissions of anything with syncros, and Mobil SHC630 in anything without syncros or clutches, like an open diff or Harley transmission.

What's the Redline going to cost you extra? $20? Less? How often do you change it? It is well worth it for the better shifting.

I use whatever I have squirreled away from my Mopar tech days. the one dealer would cash you out if you had an overstock in your box/bay. At one time, I had almost two CASES of "extra" 75w140....

In my S-10, I run the factory Synchromesh fluid. Looks like ATF, but it isn't.

The Cruiser got the cheapest GL-5 80W-90 OReilly sold by the gallon. No way I was paying $8+ a quart when the damn thing required two gallons of the stuff.

I've used Red Line in two different cars (GC Subaru Impreza, FC Mazda RX-7) with very good results. It helped cure some grinding during fast 2-3 upshifts and a noisy LSD in the FC. The shift action in both cars was much smoother, and neither is known for having decent shifting.

My Mazdaspeed3 uses Ford Motorcraft XT-M5-QS because it works well in the MS3's gearbox. It's intended for use in the European Ford Focus but both car have a similar, hard-to-shift gearbox. NC Miata and RX-8 drivers like it too. It's freaking expensive, though...

synthetic or go home. The stuff works so much better than regular.