[Gmantwo]

I replaced the TR3650 in my ‘07 GT/CS with a TR6060. The 1-2 shifting is not as smooth as I’d like so I was checking Ford Mustang TSB’s and found one that listed transmission lubricant recommendations. It listed 6 speed tranny fluid recommendation as 75W90 gear oil. 5 speeds were Mercon V. As per my trans shop, I used Mercon.
Anyone running that heavy an oil?

 

[toddturbo]

Magnums all call for Dex III only. Mine is noisy as could be. Wondering the same thing, if heavier oil might dampen some of the clattering. Called Tremec and they said let it break in and see if the noise subsides, if not call them back and they'll have other suggestions.

Did ya call Tremec? They're real easy to get in touch with-and the guy I spoke to was real fun to talk to. Gearhead-like me.

 

[Outlaw347]

TR-6060 in my '08GT500 says DEXRON III right on the side and that's what was in it when I switched to Royal Purple synthetic. I did not see any difference but other than a slight roughness in 2nd, mine ran fine and quietly with both oils.

 

[Imatk]

I've gone through Amsoil, Royal Purple, and finally Mobil 1.

I personally would not run anything but Mobil 1.

Royal Purple was a close second, but when it's cold, it's crunchy as hell and I don't have that issue with Mobil 1.

That being said... the 1-2 shift on these cars are notorious. If you do a search you'll see tons of threads about how someone "fixed" their 1-2 shift. Only to be followed by... oops not fixed.

The only thing I've read that seems to actually work or make a significant difference is changing out the synchros to the carbon ones they use in the 2013-14 6060s but I have no experience personally with that.

 

[PM-Performance]

I've gone through Amsoil, Royal Purple, and finally Mobil 1.

I personally would not run anything but Mobil 1.

Royal Purple was a close second, but when it's cold, it's crunchy as hell and I don't have that issue with Mobil 1.

That being said... the 1-2 shift on these cars are notorious. If you do a search you'll see tons of threads about how someone "fixed" their 1-2 shift. Only to be followed by... oops not fixed.

The only thing I've read that seems to actually work or make a significant difference is changing out the synchros to the carbon ones they use in the 2013-14 6060s but I have no experience personally with that.

You liked the Mobil1 even better than the Amsoil?
I swear Mobil 1 held my 160K original T5 together that was severely overpowered and had some hard shifts on it. lol. I was gonna try Amsoil in my TR6060 as I HATE the Royal purple, but maybe I will reconsider Mobil1

The thing with the 1-2 shift on the GT500's I think is people not understanding the issue and not knowing how to fix it right.

The syncros will pop if you force it when you get lockout.
Your syncros will scratch if you try to rip gears while the tires are spinning (no traction)
You will get lockout due to drivetrain geometry issues caused by tq and the engine angle shifting

The fixes are:
1. Get good tires and suspension to avoid spinning
2. Dont try to power shift if the car is spinning
3. Dont force gear changes if you feel lockout
4. FIX THE LOCKOUT ISSUES! Look at CHE Tq braces, look at motor mounts, look at drivetrain geometry if you changed your UCA and/or Driveshaft.

I was able to successfully correct my lockout issues which were comprised of geometry issues due to UCA as well as twisting of the motor/trans under load which the CHE brace fixed.

 

[Nitrous SSC]

Every T-56 and 6060 I've driven WHEN COLD will typically skip a little on the 1-2 shift. Every god damn one I've driven. The solution, don't throw a **** ton of expensive fluid into the damn thing, just let it idle for a few minutes before driving and make sure it's up to temp before beating on it like your call girl. Once my T-56 is hot when I open track it's so damn smooth. Same with my Terminator too.

 

[PM-Performance]

Every T-56 and 6060 I've driven WHEN COLD will typically skip a little on the 1-2 shift. Every god damn one I've driven. The solution, don't throw a **** ton of expensive fluid into the damn thing, just let it idle for a few minutes before driving and make sure it's up to temp before beating on it like your call girl. Once my T-56 is hot when I open track it's so damn smooth. Same with my Terminator too.

That being said, TR6060's are not known to be smooth transmissions by any means. Talking to the owner of MGW, he even referenced it to being similar to driving a Catepillar. lol
I agree though that on colder fluids it tends to be notchier from the 1-2 even on light low throttle stuff until it warms up