Funny, the guys at GM told me to change it every 25-30K miles. I know they don't know everything but the MT has all the holes needed to change the fluid as easy as the oil. I've changed mine every 25-30 miles for years now and had no problems.

For the record, I use redline D4, ATF

Decided to go with the Amsoil Synchromesh. Got everything back together yesterday.

Wow, what a difference! this is probably the best investment I have made yet!. Shifts are incredibly smooth! :)

I usually cannot tell much change when swapping between brands for "proclaimed gains", so I wasn't expecting much change with the new fluid. This was not the case.

I highly recommend this fluid, or similar synthetic synchromesh fluid, to anyone who is still running the original Dextron III ATF in their F23's.

I might have to do that some time. Mine shifts a little rough in the cold weather. It probably has Dexron III (there is no "T" in Dexron). The dealer replaced an axle seal not too long ago on it.

You are right! my mistake.

Cold shifts can still be a little stiff, but once it warms up shifts are smooth.

Hey Guys,

I have recently sold my Alero and purchased a 2007 Acura TL Type-S. I have been going through and reading a lot of standard maintenance items. 1 involving changing the manual transmission fluid helps with a problem where some vehicles where popping out of 3rd gear.

I had been noticing on my Alero that shifting into gears was a LOT harder than i remembered it being (was the only owner of a 2003 GX 5 speed with 177,000 miles on it).

If i still had the car i would for sure try this, and i see that is has already been mentioned. But i think it bears repeating!

There is a Red Line version and a GM/AC Delco version that have been raved about.

Synchromesh Manual Transmission Fluid FRICTION MODIFIED! there are versions without the FRICTION MODIFIED, but that is not what you want.

The old part number was #12377916, but is now #88900399

I wish i knew about this years ago... I hope some people out there find this useful as well.

Sorry to resurrect this thread, but i think there is a TON of Value in it!


P.S. This stuff not only solved the issue of the gear popping out of third, but it was RAVED about for making the shifting Smoother!