Hi, figured not to tack on to an antique thread that would toss email to tons of folks so here's another one.
Doing a clutch job and will need to refill the trans. Manual says only Dextron II or equivalent as others could damage parts. So is the current
Dextron whatever number the right thing for ATF and is synthetic good as well or a definite no no?
Thanks again

 

Generally the newer ATF specs are backwards compatible. Synthetic helps a lot with manual trans that use gear oil, for when the temps dip down, but with ATF being as thin as it is, it's not as much of an issue.

 

That's what I was thinking. Thanks

 

I put the Amsoil Synchromesh in my transmissions

 

I used Amsoil OE ATF in the bird I just replaced the clutch on - seems to work just fine. I'm an Amsoil dealer and it was on hand. I don't carry the syncromesh in stock.

GD

 

Walmart brand ATF, Mobil 1 ATF, royal purple synchromax, Max life ATF all seem to work the same. Running synchromax now no issues.


http://www.royalpurple.com/product/s...mission-fluid/
Royal Purple® Synchromax® is recommended for manual transmissions that specify an automatic transmission fluid

 

As you know the WC T5 calls for ATF. The ATF GM used back in the days was Dex3.

Redline D4 is a Dex3 type ATF and is full synthetic.

RP Synchromax is specifically designed for manual boxen which call for ATF.

I just drained and filled my WC T5 a month or so back. I used RP Synchromax. I used the same on the previous fill. Works for me.

 

This gets outside of the third-gen OEM transmissions, but I'd be careful with the blanket statements re: ATF in manual boxes. For starters, Dexron VI has been removed (it was temporarily suggested, then recalled) for use in the TR6060 transmissions. Friction characteristics of the fluid used in an automatic are not the same needed in a fiber / carbon / bronze blocker ring manual box. Too low a coefficient of friction in a lubricant fails shift characteristics when used.

On the colder temps and gear oil boxes, the bronze blockers in the early TR6060 line had problems with cold weather drivability shift characteristics. This mainly showed up in 2nd and 3rd gear problems, which are the gears into which most aggressive shifts are made. Gear oil would be thicker than ATF in the (lots more than most people think) boxes that tend to use gear oil., but the ATF shift characteristics would be better in a box than can use either.

Nothing about Dex VI is beneficial to a WC T5 over Dex III. Not shifting, not lubrication, and not temperature. A splash lubricated, synchromesh transmission and an automatic have significantly different operating condition concerns.

Dexron Mercon / Dexron III are absolutely fine in any third gen manual box. GM Synchromesh is another good option. Going with the newest ATF isn't going to help and could hinder shifting. Going with synthetic ATF has been problematic with carbon blocker boxes' shift characteristics.

 

Thanks, I think I'm just going with the standard OReilleys Dextron II-III equivalent. That ought to work. And for kicks I figured to replace the 28 year old trans mount while it's out.
Couldn't hurt and may help out for cheap