SladeX

After searching here and various forums, I was not able to find a definite answer on what transmission fluid to use.

Worst yet, there is a long running debate on synthetics possibly wrecking pre-01 blocker rings and causing rust on 01+ transmissions. Using a combination of different forums, from ls1tech to bobistheoilguy to even honda, I've come up with some definite answers per say as to help out the novice choose a transmission fluid.

First off is the most important. Hygroscopic vs non hygroscopic transmission fluid. Hygroscopic is the ability of a non water based fluid to absorb water. In our case, we do not want hygroscopic fluid. Since our transmissions have a vent hole which is exposed to atmosphere, the ability of the fluid to absorb water is a BIG issue.

Most ATF Dexron III fluids are non hygroscopic. I did come across a brand that scared me though. Redline. Redline is ester based supposedly and esters will ABSORB water like a wet sponge. This confirms a story of a vette owner who had switched to redline and had the fluid fail on him and GM NOT honour the warranty due to him using a non SAE certified oil. I looked into it further and redline doesn't have even half the certifications for oil that amsoil or mobil 1 has.

This alone will keep me from their products, but finding 1 story of it on the internet AND a corresponding story in real life (a friend of mine works at a local dealership as a service rep and also drag races 10 second cars on weekends). He told me that redline is a no go for transmission fluid and will go as far to say to me that any car that has had it replaced with it will not have its warranty upheld.

Now to the other brand choices. This leaves everything on the market as fair game to use. Depending on your climate though, I have some recommendations that you can note to yourself.

We know synthetics have better cold use properties than dino oil equivalents. When cold I noticed my transmission felt less notchy with synthetic over conventional oil.

Amsoil would rank higher than Mobil 1 in quality, but mobil 1 is still ahead of conventional oils. Just to give an example, I flushed my transmission out with conventional dexron. Even when warmed up, I would still have a second gear grind at WOT. Mobil 1 had NO such grind when warmed up. (I didn't test when cold as that's just dumb). Royal Purple has also been given the ok in most boards as well so for the big 3 populars, the stories are good.

GM syncromesh, also the same formula under the penzoil flag, which also carries the quaker state flag is a semi synthetic. Good choice, but GM has switched to Dexron VI now and is touted as long life. Given their history with Dex-Cool and its "long life" I would still switch this stuff out at the same interval you would any other fluid. I'd also recommend an oil analysis too.

Honda ATF Z1? is also a popular choice on some boards, and have not noted any horror stories.

If the climate you live in is warm for the most part I'd recommend go with what your wallet says is ok. Properly maintainence coupled with proper operation will lead to a more or less bullet proof T-56. (Proper operation includes not ripping through the gears until the transmission is up to temp as well, and that means driving it easy for a good 5-10 mins).

A cold climate would benefit from synthetic. Early spring (ie now) sees temp swings from 40F - 70F for me in a day. Definitly a cold start improvement over conventional.

If your transmission is exhibiting light wear conditions (popping out of gear and low rpm grinds are more serious wear), I'd recommend a synthetic. (and a good flush as well) You grinds = metal on metal breakage. My flush looked like pearlescent paint. This is still a temporary solution as the damage is still already done, but at least there is a possibility of a even partial solution. Synthetics should allow quicker syncronization and lubricate better in general. This in theory could be the difference in a light grind and no grind.

If your transmission is exhibiting signs of more serious wear, stuck gear, low rpm grinds, popping out of gear etc, no fluid on earth can fix that. Bite the bullet and repair.

Hope this makes choosing an oil easier, because quite honestly I found this the most confusing decision to make for my t-56 thus far.

Here's some of the links I used to research, I will post more as I find them so you can see for yourself.

Blocker ring debate
https://ls1tech.com/forums/manual-transmission/131374-ending-speculation-blocker-rings-who-s-had-them-fail.html

Dexron VI
http://theoildrop.server101.com/ubb/...=000450#000000

Hygroscopic definitions
http://www.ls2.com/forums/showthread...threadid=13161

Types of wear and what to repair
http://www.ls2.com/forums/showthread...threadid=90324

The guys responsible for creating our transmission
http://www.ttcautomotive.com/English/products/T-56.asp

Redline discussion
http://theoildrop.server101.com/cgi/...=002287#000000

calhoon

iTrader: (6)

This is a good , factual and insiteful write up. I hope that many can avoid pitfalls by your experience. Unfortunately anyone can post any crap they want on oil or addetives as I am sure you found on your quest for the right oil. Lets hope the LS1Tech community recognises the help this is.I thank you for it.

MeentSS02

iTrader: (11)

Hmmmmmmm...makes me wonder how my Specialty Formulations Synchroglide will hold up? Didn't really do much research, just put it in. Works great though