Firebrian

I've read many years worth of manual transmission fluid posts on here over the past 4 years in order to find what is optimum for my T56. Like most people have found, there isn't one right answer. What I don't find in the posts are the actual viscosity of the various oils and the pros and cons of each. Note that the OEM recommended ATF's (Dex 3) are in the 7 cSt range while the synchro-meshes are typically in the 8's and 9's. The newer Dex 6 is around 6 cst which is quite thin for a T56. The 8's and 9's often more gear protection than the 7's. The synchronizers need a combination of anti-wear as well as friction modification to operate best....thicker and more slippery may not work so well.

There's probably an optimum mix between performance, transmission part's longevity, parts/seal vs. oil compatibility, oil longevity, etc. It comes down to how you personally use your car. The ATF's have a weaker additive package (anti-wear, no extreme pressure additives, friction modifiers) than the dedicated manual transmission fluids. That could be very important to someone who races/tracks their car or wants it to last 150K-200K miles. It's more than just synthetic vs. dino.

MolaKule's Bitog thread on synchromesh transmission oils. The most current list of oils is on the last 1-2 pages.

http://www.bobistheoilguy.com/forums...pics/1231182/1


Here is an updated list of dedicated GL-4 and a few GL-5 MTL's, Updated 8/12/2015:

A. These MTL fluids are closest to a Kinematic Viscosity of 6.xcSt@100C (About the same viscosity as a DexronVI) and SAE 70W to 75W or so are:

1. Castrol Syntrans FE 75W,

2. BMW (Pentosin) MTF-LT-3,

3. Honda MTII or MTF 2.

4. Ford FML-XT-11-QDC

5. Volvo Manual Transmission Fluid (6.4 cSt) [Recommended for: type M65 5-speed with 6-cyl. engine, M66, MTX75 and MMT6 and of the type M56, M58 and M59 from and including model year 1996. Meets Ford specification WSSM2C200-D2]


B. The next higher viscosity MTL would be the 7.0 to 7.5 cSt@100C versions (About the same viscosity as a the original DexronIII/Merc)

1. Royal Purple's Synchromax

2. Ravenol MTF-2

3. Honda MTF

4. VW part number G052512A2

5. GM Manual Transmission and Transfer Case Fluid (pn 88861800)

6. BMW (Pentosin MTF 2) MTF-LT-1, 2

7. Tutelo (Petronus, Italy, Product Code 1402)


C. The next higher viscosity MTL would be Castrol Syntrans V FE 75W-80 8.0cSt

D. The next higher viscosity MTL would be BG Synchroshift II 8.2 cSt

E. The next higher viscosity is Mopar Type MS-9417 MTL 9.0cSt

F. Valvoline MTF Part Number 811095 9.2 cSt

G. The next higher viscosity MTL would be Pennzoil Synchromesh 9.3 cSt


H. The next group of MTL’s are in the 10.x cSt (SAE 75W80) range:

1. Redline MTL 75W80

2. Amsoil MTF (9.7 cSt)

3. GM Synchromesh’s

4. Volvo MTF 645

5. Fuchs TITAN SINTOFLUID SAE 75W-80 synthetic MTF (Carries a GL-5 rating as well)

6. Lodexol (Morris Lubricants) MTF


I. The next higher viscosity MTL would be a 12.0cSt@100C and SAE 75W85:

1. Redline MT-85 – 12.0 cSt


J. The next higher viscosity MTLs in the 14-15 cSt ( SAE 75W90) range would be:

1. Amsoil MTG

2. Redline MT-90

3. Castrol Syntrans Multivehicle 75W-90

4. Castrol Syntrans Transaxle 75w-90

5. Ford XT-75W90-QGT (Carries a GL-5 rating as well)

6. Ford MOTORCRAFT® Full Synthetic Manual Transmission Fluid XT-M5-QS

7. Subaru Extra-S Gear & Transmission Fluid carries a GL-5 Rating because it is used in common sump driveline systems.


Edited by MolaKule (08/11/15 04:49 PM)

dailydriver

Thanks for posting this, as most on here have never seen it.

The Red Line D4 Dex 3 ATF claims to give GL-4 level gear protection, even though it cannot be rated that way.

BALLSS

Quite the breakdown, informative.

The Viscosity issue aside there can be conflicts between dino vs synthetics in terms of having any adverse reaction to internal blocker rings or seals.

Back when the T56 had paper blocker rings (IIRC pre 99), synthetics supposedly made those start to dissolve over time. The later T56 has carbon blocker rings so synthetics are OK

While I have used Redline D4 which I felt was very good especially on cold shifts, I just use NAPA brand Dex 3.

Not saying Redline or DEX 3 is better than any others.

I bought a new T56 back in 2005 (94-97) and when I asked about other than DEX 3 I was advised that the Manufacturer, in this case Tremac, specs DEX 3 because that is what they test with and don't go through every brand/type (Mobil 1, Pennzoil, redline, etc) for testing. They did say, D&D, that the Redline or Mobil 1 would be fine

Firebrian

That ranking by viscosity was new to me just a few months ago and got me to thinking if there was a better choice for my own T56 than what I was using, especially concerning the additive package. I'm just presenting the info and let each person make their own choice. I like the idea of essentially a GL-4 rated ATF.

The majority of sources will state that the cellulose lined blocker rings/synchros were used on the F-bodies prior to 2001. Since I have a 1999 that's certainly a factor in my choice of fluids. Then again, you can find "reliable" sources on LS1Tech.com and/or Bitog that are certain all the 1998-2002 F bodies came with paper blockers. Hard to refute a transmission shop with over 600 original T56 rebuilds where every one supposedly had paper blockers. I don't know. Molakule also noted that the "paper" blockers are a composite of kevlar/graphite/cellulose, and not unlike a brake pad or clutch disk.

There are supposedly some synthetics that potentially can react negatively with even the carbon blockers. It's hard to separate past anecdotal "evidence" and long-held myths from reality today. So I won't try to. In reviewing literally hundreds of threads and thousands of posts, it would seem that 95% of us can use most any of the more popular ATF or manual transmission fluid in the 6.4-10.0 cSt range in our T56's and get away with it during our term of ownership. However, that doesn't prove it those were the correct or optimum fluids for the application/usage. And for every one of those choices, I found some people saying they had a problem with them, with cold startup notchiness being the most frequent.

BALLSS

yes I have also read/heard that some synthetics can react negatively, even with carbon blocker rings, but was told by D&D as long as a fluid is "DEX 3 compatible" it would be OK

Which fluid would be the best???....I don't think anyone has, or will, do 100k mileage use testing on every brand/type of "dex 3 compatible" fluid available on the market

I have only used DEX 3 or Redline D4 and can say the Redline cold shifting was noticeably better

Spectre86

iTrader: (42)

texas drivetrain t56 here. GM ATF. just like texas drivetrain told me and several other people running built T56s

Firebrian

https://ls1tech.com/forums/manual-tr...t56-fluid.html

This poll taken in 2005 on what T56 (M12) fluid you were using included over 600 participants. It only allowed 4 choices but still gives an idea of what people were thinking back then. Most every possible choice is included somewhere in those nearly 300 replies. There are even more choices available today. The 1998-2002 F bodies used T56 M6's.

Dex 3 ATF 35.5%
RP Synchromax 29.9%
GM Synchromesh 25.7%
Red Line D4 ATF 8.9%

dailydriver

For what it's worth;

My now 180+K factory T56 (took delivery of the ordered car new, in 1/2000) has had either Red Line D4, Red Line MTL, or some mix of those two in it for most of those miles/years.
(Other than those it was Amsoil MTF, Pennzoil Synchromesh, M1 ATF, or mineral Dex 3 for short fills/periods of time.)

I currently have no problems shifting, no grinding of any gear, and only an occasional popping out of gear on a 3rd gear, downhill, 'in-gear coast down', which I beleive to be just from normal, high mile, wear and tear.

The ONLY fluid I ever tried which gave me problems to the point of FORCING me to change it immediately, was the RP Synchromax stuff, which ground EVERY gear, as soon as it was in, in warm/hot weather.
I dumped it, wasting ~$85.00, two hours after installing it.

Firebrian

Thanks for that input DailyDriver. With you having tried numerous fluids on the same trans in a cold winter climate, that speaks volumes, especially on the paper blocker ring synchronizers. I suspect that the 29.9% of positive poll response above for the RP synchromax is because all those later T56's were on the carbon blocker rings.

Ferocity02

iTrader: (60)

I've tried Mobil 1, Penzoil syncromax, and Redline D4 and I liked the Redline the best. Smoother and easier shifts all around. But the difference was minimal.

dailydriver

Yes, for some reason the blockers did not 'like' the RP SynchroMax, and my guess is that "Synerlec" anti-friction/anti-wear additive they put in it lowers the coefficient of friction too much to let the blockers 'grab' correctly without grinding.

At MolaKule's suggestion (for a higher gear protection level, while still being in the 6.9-7.6 cSt @100*C viscosity range), I also tried the German Ravenol MTF-2 last year, but it shifted no better than any of the others, cost more, and is VERY hard to come by (only one seller in this country).

So I went back to the D4.

Firebrian

With 180K+ miles to date on your T56, it would appear you already have achieved outstanding "gear protection."

dailydriver

Yes, I WISH the same could be said for my lifters, and oil pump o-ring seal.

SSSTANG#1

iTrader: (14)

I'm glad I ran across this thread...

First off, what is your definition of "notchy" when talking about shifting a transmission?

I recently rebuilt my T56 Magnum and replaced 1-4 blocker rings with TUES10357 carbon fiber blocker rings. A reputable T56 builder recommended Amsoil Synchromesh so that's what I used. The transmission is very cold natured. It grinds if I don't shift very slowly when it's cold and gets only slightly better when it's warmed up.

It shifted better during brake it in with dex3 but I need more gear protection especially for the input gear and cluster. What would you recommend?

Btw, the car will see the drag strip and has 700+ hp.

Thanks.

Robert Cantu

iTrader: (2)

Using Redline in mine it seems to like it alot.

BALLSS

I found Redline D4 improved cold "notchy" shifts. Try it and see if your situation improves

Firebrian

No expert here. All I can say is I've read a thousand or more posts on what everyone else has done with their T56's and how it's worked for them. DailyDriver above has tried numerous fluids, most of them successfully.

"Notchy" probably means something different to each one of us. Even on regular Valvoline dino ATF my trans is slightly notchy in the first mile of shifting, especially 1-2. Since I'm warming up the car for the first 5 miles or more that's a non-factor. I have read enough posts on the higher viscosity MTL's (ie higher than ATF visc) that not everyone ends up liking them. The Amsoil synchromesh linked below has a 9.7 visc at 100 deg C. That puts it at the higher end of the synchromeshes. Pennzoil synchromesh is at 9.3. Getting closer to the ATF viscosity range of 7.0-7.6 would probably help you. Choices there include Mobil ATF, RedLine D4 ATF, and Amsoil's own brands of multi-vehicle ATF (7.5-7.6). You could also consider the MTL's in the 8.0-9.3 range that are on the list in the orginal post. The Amsoil synchromesh at 9.7 appears outside your comfort zone.

https://www.amsoil.com/lit/databulletins/g2080.pdf

If you want to stick with Amsoil I'd discuss the above choices with your builder and an Amsoil rep. I think the Amsoil ATF's would have been a better choice from the start, at least for ease in shifting. The Pennzoil Synchromesh at 9.3 is at most a synthetic blend. The slight drop in viscosity and not being a pure synthetic could make it easier in your synchro's engaging. There are also track and drag cars that do just fine on a quality ATF. If it were me and I had concerns about minimizing gear wear while getting smoother shifts, I'd try the Pennzoil synchromesh MTL. No guarantee that it makes anything better for you. If does offer more protection than most or all of the ATF's.

dailydriver

^^^Yes, although the Amsoil Synchromesh is one of the thinner, readily available (some of those 7.5 cSt range MTLs on MolaKule's list are hard/impossible to come by), MTFs (it is ~1 cSt lower viscosity than the Red Line MTL), it is still too thick for a cold ambient temp environment until warmed up.

It might be just fine in southern Tejas, or even the deep south, in the summer, where it is already 100* F outside in the early AM when you get up and start it, but for anything else, it will grind until warm.

The Red Line D4 will probably give about the BEST 'gear protection' of ANY of the various Dex 3 ATFs.

LS1-450

iTrader: (33)

If the owner drives @ extended periods of high RPM &/or @ max torque, GL4. It is not the gears that take the hit, it is the small roller bearing that seats inside the input shaft & the large bearing in the face plate that wear quickly.

Even on upgraded transmissions, once the input shaft start flopping around, it will be difficult to shift into 4th gear @ high RPM/TQ & the slop will crack the coating on the ID of the synchro/blocker ring.

If you only street drive, I wouldn't be overly concerned about trans fluid. Road course driving is where the issue will happen most. Maybe drag racing, but, it would have to be several times a month.

Bottom line, if your input shaft wriggles by hand, pull the front plate & check the areas described.

Firebrian

http://www.svtperformance.com/forums...ing-over-stock

The Ford SVT guys haven't had any better luck figuring out the "best" fluid for a T56. I was surprised at how many had good luck with the RP Synchromax....and a lot also noticed no difference. Like in our long "What T56 fluid to use" thread, lots of good luck with Mobil 1 ATF, GM/Pennzoil Synchromesh, Redline D4, etc. And plenty of detractors saying they didn't work out well for them.

Even some of the things Tremec says in this thread in response to owner inquiries don't seem to be consistent. For example in one utterance, they state that paper blocker rings went out by 1997. And then you have original T56's from as late as 2004 showing up with paper-lined blocker/sychronizer rings. The one thing they did say that made sense is listed below.


Service Topics Number: 2-03

Date:
March 14, 2003

Subject:
Recommended Fluids

Transmission Models Affected:
All

Due to various synchronizer materials used in TREMEC transmissions, and different climates and applications, no one single fluid will work for all transmissions. For example, fluids that are high in sulfur content may damage the surface of brass blocker rings found in many transmissions, while some oils may damage the bonding material used in carbon fiber papers. Heavy weight oils generally provide better lubrication to bearing surfaces; however they may cause harder shifts, particularly in cold weather.

Recommended oil change intervals should be based on specific usage. In most cases a “fill for life” is adequate, while in severe applications such as drag racing, or road racing a more frequent fluid change should be prescribed. Excessive heat will cause most fluids to breakdown and ultimately cause damage to the transmission. The transmission should be filled through the fill plug located on the side of the transmission. Proper fill level is achieved once the oil reaches the fill hole. Recommended fluids by transmission model are listed below:

TR-3550 / TKO
GM Synchromesh has proven to provide the best performance for these transmissions, which use brass synchronizers.

T-5, T-56, TR-3650
These transmissions use a combination of brass, carbon fiber and paper-lined synchronizers. An ATF fluid such as Dexron III will provide the best results.