Firebrian

I had the factory fill in my 1999 SS (paper lined friction rings/blockers) for 13 yrs/12K miles. Since I didn't own it then I can't say how it performed. I changed that fluid to Valvoline Dex 3/Merc a couple months after getting it. Ran that for 5K miles and noticed no real difference either way. This year I changed it to the GM recommended 88861800 even though it's probably just plain ATF Dex 3H with a typical weak ATF additive package. Again, no differences noted from old factory fill, to Valvoline Dex 3 to GM MTL. I'm happy with the shift quality under all of them.

I'd like to try the Amsoil ATF torque drive, Redline ATF D4, Honda ATF, even Mobil 1 ATF, or Valvoline MaxLife ATF as they have stouter add packages that will reduce the wear on the transmission....with a possible trade off on the synchros being a little less likely to grip as they would under conventional ATF's. At the same time, I've read enough posts in hundreds of threads that show not everyone has good luck with the synthetics. I've yet to read anyone saying that Dex 3 caused their transmissions to fail/wear out early, some going to even 200K miles on factory fill! So the easy choice is to just stick with conventional Dex 3. The Valvoline MaxLife is interesting as it has a very stout additive package for an ATF. My only concern is the low 100 deg C viscosity rating of 6.0 (min Dex 3 spec if 6.8 and most are in the 7.0-7.6 range). That 6.0 is similar to the viscosity of the Dex 6 which is not recommended for the T56. I know some people have used the MaxLife in their T56's with success....at least for tens of thousands of miles.

Unless you've used a single fluid for 100K miles or more on a T56 you really can't say if you gained or lost from the normally expected lifetime. The people recommending the MaxLife indicate that it's less prone to shearing than conventional Dex 3's. That's probably true....and even PQIA has removed the caution they placed on it for not meeting technical Dex 3 specs, in particular the low viscosity. After 5,000-10,000 miles on your Dex 3 it's viscosity may have dropped from 7.5 to 5.5 while the MaxLife could still be at 5.5-6.0. One UOA I read on a factory fill 2010 Corvette 6 speed showed the Dex 3 had sheared down to 5.3 in only 8,000 miles. So for me, I'm still using the Dex 3/GM MTL/ATF but will change it by 3K-5K miles. The GM MTL/ATF is not that expensive either. I found it for $6.50/qt at a local supplier.

Boxxx

I found a GM TSB that said to use their manual transmission fluid 1#88861800/10-4033 so that's what I did, from looking at it and reading the contents on the bottle it's just Dexron III with additives to improve it for use with manual transmissions. Hell the first component listed on the bottle is automatic transmission fluid. For what it's worth it made a notable improvement over the slightly used ATF that was in there in shift feel, smoother going into the gears being the best way to describe it I guess. Also I was able to find it on Amazon for under $6 a quart shipped as an add on item for Prime members. It's gone almost 120K miles on Dexron III and shifts out like a new transmission, so that's good enough for me to use the GM MTF and not want to experiment. It still boggles me the owner's manual says fill for life though, thankfully the previous owners didn't pay any mind to that.

Firebrian

Boxxx, if you can post that TSB or just list the makeup of that fluid I'd like to know what's in it. I've never run across a breakdown or virgin oil analysis of the stuff. I've always figured it was just plain old ATF with nothing special added (possibly just an exact copy of Havoline or Texaco ATFs)....didn't think it had the more plentiful anti-wear additives found in Honda ATF, Redline or Amsoil ATF's. Would be nice if it did.

Boxxx

This isn't the TSB I found originally but this TSB briefly mentions the change at the bottom of the first page: http://www.revbase.com/BBBMotor/Tsb/...dPdf?id=168779

Then here's an image of the back of the bottle that's good enough to easily read: https://images-na.ssl-images-amazon....L._SL1500_.jpg

Firebrian

Thanks for posting that Boxxx. Wasn't familiar with C5-30 and C20-50 petroleum, hydro treated neutral oil base, etc. But, it in looking them up I don't get very far. Probably just base oils that are part of the oil concoction. And since no % is given, they could be anything from 1% or higher. Nothing found on additives like Ca, Mg, Boron, etc. I think I looked at the AC Delco bottle a while back and just stopped reading after seeing ATF as the first ingredient.

https://www.bobistheoilguy.com/forum...ex#Post2984359

The above is a 3 yr old post on Bitog showing a UOA for the GM MTF factory fill on a 2010 Vette after 8K miles. It sheared from the mid 7's down to 5.36. The additive package looks a bit weak for an MTF....like any generic brand ATF Dex 3. The numbers below are what Molakule (a former ATF/MTF specialty blender) listed for GM 88861800....which I don't know is sourced to any base data.

Boron - 105 ppm
Calcium - 25 ppm
Phos - 325 ppm

Other AW and organic additives included.

Vis@100C = 7.5 cSt.

https://ls1tech.com/forums/manual-tr...-others-2.html

http://www.rsgear.com/articles/upgrade_T56.pdf (go to "support" then "technical articles")

http://www.ls2.com/forums/showthread...ns-amp-Answers

http://www.corvetteforum.com/forums/...bon-fiber.html

https://www.bobistheoilguy.com/forum...&Number=504495.....what the forum was thinking on this topic back in 2003/2004.

...T56 synchronizer at 11:00 of the video.

Boxxx

I searched a lot before ending up with the GM MTF, could never really find anything conclusive on the benefits of using something else in lieu of Dexron-III with some actually causing problems. What I did find though for sure was that the paper blocker rings are sensitive and Dexron-III was used for that reason so it made sense to play it safe and use the GM MTF. Personally I rather change fluid out more often than risk using something that'd potentially cause issues.

pozesd99'

iTrader: (3)

I usually run amsoil torque drive. This last time caused me to waste 1 gallon of it due to clutch issues and having to pull trans. Autoparts store had some valvoline max life atf. Will this work fine with my built t56?

Firebrian

I'd stick with the Amsoil ATD even with the extra cost. The Max Life will probably work. While it does start off as a low visc ATF (6.0 at 100c) yet doesn't sheer like a conventional generic ATF. Those can drop from 7.0-7.5 to 5.5 in 5K-10K miles of spirited driving. The add pack in the Max Life is pretty good for a budget ATF. The fact that Max Life says it works for both Low Viscosity and Multi-viscosity transmissions seems a bit too stretched for me. I'd run it by your trans builder first. For some built T56's that will see higher temps on the track, Tremec says Pennzoil Synchromesh is a suitable choice. I think that's a semi-synthetic fluid.

pozesd99'

iTrader: (3)

Is this the redline trans fluid that is recommended?
http://www.tickperformance.com/red-l...fluid-1-quart/

pdxmotorhead

FWIW,,, I grew up with the son of a Chevron Chemist, according to him ALL atf is at least partially synthetic. Its basically a extended service hydraulic fluid, similar to what we used to use in the consolidated wet clutches in tractor transmissions.

Dextron was introduced pin parallel to the Powerglide Trans and the old power-glides had funky paper looking clutch material in them for the bands... So maybe that's the connection to the fiber synchros and fluid??

In any case I have a AX-5 tranny in my jeep and it is very sensitive to teh differences between GL4 and GL5 gear oil, so not too surprising other trans missions are similar I guess. Like the unicorn blood that that GM NV-4500 5 speeds required... Use the wrong stuff and poof empty wallet.

Firebrian

Yes. Redline ATF D4 is typically recommended for those manual transmissions that are compatible with synthetic ATF's. I hear it mentioned as often as the Amsoil ATD ATF. Curiously, I read some owner posts where one worked fine for them but not the other.

Boxxx

This reminds me of the posts on the Getrag V160 and what should be used with it. Toyota's V160 fluid at $50 a litre is more or less ATF, so there're a lot looking for suitable alternatives. Never mind the fact most of their 20 year old cars are still worth $20K+ so what's $100, but should I digress... Anyhow here was a test done with the V160 fluid and others some might find interesting: https://www.pdf-archive.com/2014/02/...review/page/1/

BALLSS

Good stuff for the T56 with the newer carbon blocker rings vs the paper ones. My 94-97 T56 was purchased new in 2005 from D&D and they said Tremac was building them with carbon blocker rings by then so I have used it. smooth shifting especially when tranny is cold. Not cheap so I just run standard DEX 3 which has been fine for several years now

Firebrian

That's an excellent comparison of various fluids. Very interesting. Thanks for posting that. The Castle ATF was worse than even the most generic ATF's listed on PQIA ATF samples. The Jack's fluid was very high in AW and EP additives. That would likely cause issues with the early T56 composite cellulose/kevlar/graphite synchronizer friction rings. The Valvoline MaxLife ATF has add pack numbers similar to M1 synthetic ATF and the Honda ATF Z1/DW1. But MaxLife is basically a Dex VI...and therefore not recommended as a manual transmission fluid in the T56.

As a comparison the GM MTL/ATF 88861800 has visc 7.4 / Boron 105-135 / Ca 25 / Phos 230-325 from information I've run across. That's a little bit stouter than the Castrol Trans Max. Compare that to GM synchromesh visc 9.2 / Mg 5656 / Phos 1965 / Zn 1275 / Ca 86. Pennzoil synchromesh is very similar. Both of them are strong GL4 manual trans lubricants.

http://www.svtperformance.com/forums...sh-or-Pennzoil

https://www.bobistheoilguy.com/forum...Number=1231182

Valvoline Dex/Merc conventional ATF is readily available out there: visc 7.4 / 272 Ca / 21 Phos / 75 Boron. It has plenty of detergent (Ca) but is lacking in AW additives. I've used it before...but would not in the future. This has the Ca and Phos levels sort of reversed per the 2012 PQIA tests. The Valvoline Max Life tests out excellent with a strong add pack.... but still has to contend with the low 6.0 viscosity which is better suited in an automatic trans.

https://www.bobistheoilguy.com/forum...Number=3024750

Exidous

iTrader: (11)

I'd like to add my most recent trials to finding a good ATF for my T-56. I have the carbon blockers and nothing ever really made me happy. The Redline D4 was pretty close. A couple hours of research looking at data sheets I came to Redline D6.

My issues were never how it ran hot. Once the trans was up to temp there were a couple that all did well. When cold they were all too thick. The colder it got the worse it would shift. Usually in the form of grinding due to the blockers not grabbing. The D6 when hot is only slightly thinner than the D4 but when cold it's a good 25% thinner. This made a huge difference. It's still not perfect but damn near close.

Firebrian

D6 sounds like an interesting alternative, though it's specifically not recommended by GM for the T56's. I wonder if the D6 is more shear stable than the Redline D4? Both meet GL-4. Here's what Redline says about their D6.

Synthetic D6 ATF is a lower viscosity version of the D4ATF and is designed for better fuel efficiency in CAFE testing. Dexron VI requires a different approach to a conventional ATF formulation. Rather than beginning with a 7.5 cSt fluid and allowing a viscosity loss in use to drop to 5.5 cSt, the Dexron VI fluid requires a starting viscosity of less than 6.4 and a final drop to no less than 5.5 cSt. Red Line D6 will drop to no less than 6.1 cSt. Since the final viscosity after use of these fluids are similar, Dexron VI fluids can be used where Dexron III fluids were previously recommended (with the exception of some manual transmission applications, our customers report). D6 ATF also provides significantly improved gear protection and will provide a GL-4 level of gear protection.

Exidous

iTrader: (11)

I'd be interested why it's specifically not recommended. It's working quite well for me. I will admit the transmission is a little noisier than before but it's mostly due to the cam.

Firebrian

I've always assumed that the drop in viscosity from Dex III (7.5) to a Dex VI (6.0) was the primary concern. It just didn't have the high temp viscosity to properly lubricate/protect the gears. I would think either viscosity would do fine for lubricating the synchronizers and bearings. Another possible reason is that many of the Dex VI's are synthetic. That could cause issues with getting the synchronizers to grab properly (ie less friction available).

I would think the add packs in the Dex VI are a lot stouter too. More (or less) AW additives "could" cause issues with the synchronizers years down the road. I know some experts have stated that any GL-4 lubricant designed for a manual transmission has the proper friction characeristics designed in for optimum synchro operation. While I know that was the intention, the large number of people having "some" problems with those GL-4 synthetic fluids is hard to dismiss. Alternatively, you can find owners who have never had a problem with any particular fluid, even if not recommended for their car. All you can do is weigh the pros and cons for your own application and make a choice. I've never run into a post that someone said Dex 3 ruined my Tremec transmission (ie the factory recommendation). Yet I can find dozens of anecdotes where any of the after-market fluids caused issues in transmissions designed for Dex III.

Exidous

iTrader: (11)

That all makes sense. I tried DexIII but was never happy with the cold operation. Only tried the standard Mobil DexIII ATF.

I think that it would have been fine with the paper blockers of the early T-56's but not so much the carbon ones like I have. I'm also curious if having the blockers saturated with so many different fluids over the years could cause issues. If I'm feeling energetic and happen to have the trans out I'll probably replace the blockers just to be sure.

Boxxx

From what I've read the paper blockers will absorb the fluids or oils used and that's why using the synthetic ATFs or different gear oils can be so devastating. Living in Alabama and acquiring the car in March I've yet to have what most people would consider a cold day, but especially after putting in the GM MTF the shifting feel has been great at ambient temperature and at operating temperature. After doing the Core Shifters short stick it feels better than my Miata did, though in fairness the Firebird was taken care of a little better by previous owners.

I guess I should add I also did the shifter rebuild on the Miata from Tasca, that and I had a Voodoo aluminum ****. It felt good though, at the very least it and the Firebird have had the best of the manual cars I've owned. Though stock the Firebird felt fine shifting but the throw and height kind of killed it, the shifter stick made a bigger improvement than you'd think.