Mackitraz

So Mercon doesn't result in shifts that are as positive, but Mercon-V is sluggish and doesn't perform like it should when it's cold?

07alloygt

That statement would certainly make sense due to the fact I've owned a 07 GT and now an 08 GT. My 07 had NO problems what so ever with the tranny. However like I've stated over and over, the 08 had cold start grinding issues. If Ford switched from Mercon to Mercon-V (which is apparently not as slippery) then that makes complete sense.

RadBOSS

Been trying to find and article I came across a few months ago that explains the properties of these oils better than I probably am. If I find it anytime soon I will post it.

metroplex

While FM can increase or reduce friction, the stuff used in the Traction-Lok and Mercon-V appear to decrease friction.

Ever fill a Traction-Lok with gear oil that did NOT contain friction modifiers? The clutch packs will GROAN and CHATTER whenever you make a low speed turn because there is too much friction between the plates and clutches. The friction modifier reduces friction between those surfaces. This is the same reason why 05-06 GTs that had rear-end chatter/groaning needed some additional friction modifier to quiet down the clutch packs. This is also why you don't want to add too much friction modifier in a posi because it reduces the torque biasing capacity from reduced friction.

Ever fill an old transmission with Mercon-V when the owner's manual just calls for Mercon? I have on a few occasions. With regular Mercon, my 1980 AOD shifts pretty firmly. With regular Mercon, my 1989 C6 shifted the same way. When I switched to Mercon-V in both applications, the shifts were much smoother/softer. Back when I did the switch, everyone said I'd wear out the transmission from all the slippage (due to the extra friction modifier content that reduced the friction) but fast forward to 2005-2006 and you'll see that Mercon-V can be used in applications that call for Mercon.

I recall reading an article that indicated Mercon-V is not nearly as friction modified as Chrysler ATF+4.

My TR-3650 shifted very poorly with the factory fill ATF (mercon) and switching to a fully synthetic Mercon ATF really fixed it up. I even switched to the thickest Mercon ATF I could find. I think the bottom line is to just switch to a fully synthetic ATF in the TR-3650 and fill it to the correct capacity. The fact that 08 GT owners are complaining about grinding indicates that Mercon-V is not a perfect solution for the 3650. Perhaps the extra friction modifier from Mercon-V reduced the friction, inhibiting the efficiency of the blocker rings, causing the grinding (05-07 GT manuals require Mercon, 08 GT requires Mercon-V). The TR-6060 in the GT500 uses Mercon-V as of its initial release.

07alloygt

Again very informational. I would certainly have to agree with you about Ford's "perfect solution." So far, not enough people have seen this problem (for what reason I don't know) so there is no TSB on the issue. However, it is quite evident to me that for those who have grinding issues during cold starts, physically, it must be fluid based. I feel sorry for those who have CONSISTANT grinding issues whether it is cold or at optimum operating temperatures. I certainly wouldn't want to bring my car into those hacks at Ford.

RKNMACH

I switched to RP Synchromax because of the occaisional grinding problem I had - usually between 1st and 2nd - and at first I thought I had fixed the problem but after a few days the problem still existed, I personally believe it is partly due to the clutch system (or my laziness to fully depress the clutch pedal).

Rebel73

Wow, it's all coming together now. My 05 NEVER had these issues.

So what's the general consensus here, guys? Just live with the "cold crunch" and work around it, because to some degree it's normal with a "less slick" fluid that requires heating to work properly?

Or should I go ahead and try another fluid?

metroplex

I just read in an article linked above that said Mercon-V was using Group II / II+ basestock, which makes a pure non-synthetic ATF. However, in most of the Mercon-V formulations you find in stores, it will be a synthetic blend / partial synthetic at the least. An example would be the Castrol Mercon-V ATF. It is a synthetic blend, so it will perform much better in the cold than a cheap Mercon ATF. I have read in other tech articles that Mercon-V is supposed to use a Group III basestock which makes it a highly refined dino aka "synthetic".

That said, recall that the TR-3650 has been in-service since 2001 in various Mustangs. There is a HUGE thread on Stangnet regarding the cold 1-2 grind and other issues. I recall several people having to step on the clutch and wait 5 seconds before shifting into 2nd gear or else they get grinding and this was on the earlier 01-04 Mustangs.

Even Tremec/TTC and Ford cannot agree on the fill quantity and type of ATF. At first, Mobil 1 ATF was being used and then Tremec claimed that synthetics were "too slick" so you must use a non-synthetic Mercon ATF. They claimed that Havoline/Texaco non-synthetic Mercon ATF is what they use to test the gearboxes and that is what they recommend for the 3650. That's not accounting for the changes in the fill plug locations and methods to check the fill-level. Don't add too much ATF!

On my 2007 TR-3650, I changed it out to slightly less than 3 qt of Redline High Temp ATF and haven't run into any issues with shifting even in the winter. It definitely smoothed out my shifting to the point I can use 2 fingers to move the shifter even during aggressive 3000-4000 RPM shifting.

There are many complaints about the 05-07 3650, but I don't recall problems with grinding during a 2-3. The only difference that I can see is that Ford changed over to Mercon-V for the 08 3650.

07alloygt

I would definitely try another fluid. Like I said, I had put in Royal Purple's MAX ATF and there is no grinding after 5 cold starts.

BuzzyStang05

Yeah, I was thinking the same thing...BTW, I am running the craziest tranny fluid concoction of anyone (see sig) - but it works great for me!

07alloygt

Haha, jesus. I've heard some people even put a "dab" of synthetic motor oil in their transmissions.

RadBOSS

Well I did some more research today and came up with a interesting white paper by Redline. This is for their MTL transmission fluid (and I am not suggesting it is compatible with our manual transmissions) and it has a very good technical discussion about synchro action and why its desirable for the fluid to be less slippery and what happens when it isn't. The article shows a comparison of the friction characteristics of several oils. Its worth a read. My opinion only, but I doubt the Mercon V is causation for sticky or sluggish shifting as suggested in thread above ... the mechanics compared to the blocker ring function and the slider are entirely different.

I'll take back my point about friction modifier for the posi. This additive increases slipperyness. My bad.

RadBOSS

Grinding results when the fluid is too slick (assuming the synchros are not already toast from excessive hammering). Fluid offering a higher friction coefficient ensures the blocker ring grabs the gear quicker. What is happening is the input gear (the gear you are shifting into) RPM is matched to the output shaft RPM, then the slider can engage the spline in the rear w/o crunching or grinding.

metroplex

RadBoss: That is an excellent article. The last section pertains to our application: a manual that calls for ATF. I was sold on using MTL until Redline recommended the D4 ATF, which is just their synthetic Mercon/Dexron III ATF. However they state that MTL can be used in manual gearboxes that require ATF so I am a bit confused.

Can we safely use 3+ qt of MTL in the TR-3650? What kind of fluid is MTL, is it more of a gear oil or an ATF? Why do we *need* an ATF for the 3650? I heard that the blocker rings are a composite material on the modern 3650 which requires an ATF, and that the synchronizer cones are a paper material.

BuzzyStang05

I've been running my 50/50 mix of D4 and MT-90 (an even thicker version of MTL) for about nine months/6,000 miles now and have not had any issues at all.

BTW, the reason I buy Redline instead of Royal Purple is because of these white papers. You can tell they give a ****.

metroplex

I run Redline gear oils in all of my Fords: Dana 60, 28-spline Ford 8.8", and a 28-spline Ford 7.5". Since the 07 GT came with a synthetic 75W-140, I'm leaving it be.

The viscosity of Redline High-Temp seems to be comparable to MTL. I'm wondering if I should even bother switching to MTL.

RadBOSS

The blocker ring is the syncro cone (female). TREMEC have told me only two of the blocker rings are composite (its on my email at work). What it boils down to is whether the redline MTL is detrimental to the composite liner on the two blocker rings in question.

MTL means Manual Transmission Lubricant and looks to be a full synthetic (see attached data sheet).

The term ATF is somewhat generic as it has come to embody all the variations of that fluid, so all are not equal.

BuzzyStang05

I don't know but the last sentence there "All Red Line transmission lubricants provide excellent synchronizer compatibility" seems to indicate so, to me anyways. The white paper also says "The additive chemistry used is non-corrosive, so even though they will provide GL-4 performance, they will not corrode synchros or bushings."

metroplex

I think they inserted that statement mainly to indicate that MTL isn't like a gear oil that can corrode brass/bronze materials that are normally used for blocker rings and bushings. I suspect we may have to use an ATF due to the composite materials. More likely than not, this material may be similar to the clutches used in an automatic transmission.

On Redline's site, they mentioned that their D4? was highly recommended in the Corvette's T-56, which is the precursor to the TR-6060. I know this doesn't help us, but remember that the TR-6060 did call for Mercon-V ATF and that Ford recently changed the requirement for the TR-3650 to use Mercon-V ATF. In addition, if you ask Redline to recommend a fluid for the TR-3650, they will tell you to use D4 ATF if the transmission needs a Mercon ATF. Otherwise they recommend MTL.

RadBOSS

Thought those interested on what Redline clarified and recommended to me:

">Below are the results from the Red Line Oil web site Application Request Form.
>
>It was placed on 4/25/2008 5:28:10 PM.
>
> Application Request Form Information
>-----------------------------------------------
>Name : Paul
>Email Address :
>Address :
>Address 2:
>City :
>State : TX
>Zip :
>Make : Mustang
>Model : GT
>Year : 2005
>Engine Type : 4.6L V8
>Differential Size/Type : Ford with posi
>Transmission Type: 5 speed manual
>Issues : Trans shift is notchy and draggy most of the time. Worst
>on initial start up. Sometimes first won't engage w/o grinding on a
>down shift.
>Recommendations : Is your MTL compatible with the blocker rings with
>composite lining in this transmission (TREMEC 3650)? Your
>literature is confusing, because on one hand it says MTL is
>compatible in any trans that requires ATF and in another breath
>recommends D4 ATF as a substitute for Mercon? In terms of Mercon
>V's properties, does MTL meet or exceed Fords requirements?.

Paul,

Thank you for contacting Red Line Oil, in your Tremec 3650
transmission I would recommend the D4ATF and would satisfy the Mercon
V requirements. Sorry for the confusion, the MTL is compatible and
can be used in your transmission though is a higher viscosity so can
be a little stiffer shifting at low temperatures with synchros
designed for an ATF, it isn't an ATF but a low viscosity gear oil. I
would expect similar overall shiftability between them. Do you
experience any issues shifting into reverse? Gear clash or a
difficult reverse shift?

Regards, Dave
Red Line Oil"