Tremec T6060 fluid recommendation?

[turbulence]

I daily drive my 2023 Cadillac CT4-V Blackwing 6M in Maine. I got the car used at the end of September 2023 with 6,700 miles, and the inherent notchiness of the transmission has become significantly worse now that we're in the dead of winter and I frequently drive in below freezing temps. This leads me to consider changing the factory fill ATF based on some searching and reviews.

GM calls for a Dexron III fluid, so I'm mainly considering Amsoil Torque-drive or Redline D4, although I'm secondarily considering Mobil 1. I've read mixed reviews about D4 in these Tremecs (a few people noted no difference, while others noted an improvement), but I haven't read one bad thing about the Amsoil (although there seems to be fewer people using this, mainly Corvette guys). I also realize in warmer climates or track use, gear oil or even a mix of ATF and gear oil works really well, but I as I'm still under warranty, I want to run Dexron III exlusively because that's what the manual calls for.

BTW, I'm ignoring the 100C viscosity because my trans temp gauge doesn't ever indicate above 40C (104F), especially in winter. The hottest it gets is maybe 29C (85F).

I'm assuming I have AC Delco Dexron III (H) from the factory with the following specs:

• Viscosity at 40C: 35.8
• Viscosity at -40C: 17,430
• Viscosity index: 176
• Pour point: -51C

Amsoil Torque-drive specs:

• Viscosity at 40C: 37.1
• Viscosity at -40C: 8,278
• Viscosity index: 168
• Pour point: -56C

Redline D4 specs:

• Viscosity at 40C: 35.4
• Viscosity at -40C: 5,200
• Viscosity index: 188
• Pour point: -60C

Mobil 1 Synthetic specs:

• Viscosity at 40C: 36.3
• Viscosity at -40C: 10,040
• Viscosity index: 176
• Pour point: -51C

Based on the above specs, AC Delco seems to be the thickest in cold temps and D4 the thinest, with Mobil 1 and Amsoil in between. Does anyone have any experience with these ATFs in manual transmissions in the cold? Which would you recommend?

 

[Marcozi]

I'd contact Redline. It's tech support is very good.

 

[oldhp]

I've had 3 Challenger R/T's with 6 speeds. The best, smoothest shifting came from Valvoline DEX / MERC Dexron III. DO NOT buy the Dexron / Mercon VI.

 

[turbulence]

I've had 3 Challenger R/T's with 6 speeds. The best, smoothest shifting came from Valvoline DEX / MERC Dexron III. DO NOT buy the Dexron / Mercon VI.

You're the second or third person that's said that. I'll give that fluid a look.

 

[Spaceme17]

Tremec is now selling their own [Branded] trans fluid.

Tremec MTF specs:

• Viscosity at 40C: 71.6
• Viscosity at -40C: 65,000
• Viscosity index: 167
• Pour point: -70C

Significantly thicker.

 

[turbulence]

Tremec is now selling their own [Branded] trans fluid.

Tremec MTF specs:

• Viscosity at 40C: 71.6
• Viscosity at -40C: 65,000
• Viscosity index: 167
• Pour point: -70C

Significantly thicker.

I've seen that, but GM specs dex 3 for my tranny, and even Tremec's own support said to use the OE recommendation when I emailed them. Regardless, in my cold climate, I wouldn't want something thicker. Maybe when I'm out of the warranty period or if I move to a warm climate I'd run Tremec's fluid.

 

[kschachn]

There is no licensed DEXRON-III fluid, the approved supersession is to DEXRON-VI. Much better shear resistance and viscosity retention plus it will be a synthetic to help reduce oxidation. There is no reason to use an outdated DEXRON-III type fluid.

If you wish to try a boutique fluid that is an option but to go and look for "DEXRON-III" gets you nothing. If it were me I'd try Maxlife.

 

[turbulence]

There is no licensed DEXRON-III fluid, the approved supersession is to DEXRON-VI. Much better shear resistance and viscosity retention plus it will be a synthetic to help reduce oxidation. There is no reason to use an outdated DEXRON-III type fluid.

If you wish to try a boutique fluid that is an option but to go and look for "DEXRON-III" gets you nothing.

Then why does the manual in my 2023 vehicle say Dex 3 instead of Dex 6?

 

[kschachn]

Then why does the manual in my 2023 vehicle say Dex 3 instead of Dex 6?

Who knows. It is an improper specification anyway, no one can buy a licensed -III product anymore. Between DEXRON-III and -VI the starting viscosity is irrelevant. It is about retention.

GM themselves issue the licenses and the official supersession is to -VI, so the -VI product will work in any automatic transmission that lists -III. No boutique fluid nor the Mobil 1 product is licensed so it really doesn't matter if you are considering those fluids.

DEXRON®-VI licensed fluids are fully backward compatible and can be used in all applications covered by earlier GM ATF specifications."

"DEXRON®-VI replaces DEXRON®-III and DEXRON®-III-H in all applications except power steering and manual transmissions

All DEXRON-III licenses expired at the end of 2006, and will not be renewed. Beyond that date, General Motors will only support the use of DEXRON-VI fluids for use in Hydra-Matic transmissions.1 Fluids claiming DEXRON-III type performance continue to be sold under abbreviated names such as Dex/Merc and D/M, however, since the DEXRON-III licensing system no longer exists, these fluids are not regulated by GM in any way.

 

[turbulence]

Who knows. It is an improper specification anyway, no one can buy a licensed -III product anymore. Between DEXRON-III and -VI the starting viscosity is irrelevant. It is about retention.

GM themselves issue the licenses and the official supersession is to -VI, so the -VI product will work in any automatic transmission that lists -III. No boutique fluid nor the Mobil 1 product is licensed so it really doesn't matter if you are considering those fluids.

I see you're talking about auto trannys...I have a manual. Perhaps that's why.

 

[kschachn]

I sincerely apologize for the error, when I read "This leads me to consider changing the factory fill ATF based on some searching and reviews." all I thought about was "ATF".

Then yes you should use the specific GM fluid for that manual transmission or a boutique fluid that is specifically recommended for your transmission.

Again I'm sorry. I definitely would not use a homebrew mixture of ATF and gear oil however. Use something that is recommended for that use, or as I mentioned the proper GM fluid.

 

[turbulence]

I sincerely apologize for the error, when I read "This leads me to consider changing the factory fill ATF based on some searching and reviews." all I thought about was "ATF".

Then yes you should use the specific GM fluid for that manual transmission or a boutique fluid that is specifically recommended for your transmission.

Again I'm sorry. I definitely would not use a homebrew mixture of ATF and gear oil however. Use something that is recommended for that use, or as I mentioned the proper GM fluid.

No worries.

 

[thescreensavers]

From my 17 SS1LE that I owned for 4 years (~22k miles) in FL I have a theory that the cold running temps of the TR6060 degrades the shifting feel. If I wasn't on the track the trans fluid never got that hot, so im assuming that some amount of moisture was retained in the fluid over time.

..Anyhow theory aside, I never had an issue with the OEM fluid until some time got on it, then there was a noticeable improvement moving to Redline D4. The trans also liked the D4 better when hot (Doing a track day it was less finicky). Though with time D4 also started feeling meh in the shift feel. Drain and fill with Fresh D4 fixed that.

Fresh to Fresh fluid no one notices anything, "old" fluid to fresh regardless of flavor people feel an improvement.

I just think the TR6060 just needs fresh fluid to feel good.

 

[redhat]

Maybe this would be a good use case for some TES-295 (Delvac 1 ATF) or TranSynd? DEX III viscosity and synthetic. I like to think of it as all the good from DEX V.I. with the III viscosity.

 

[turbulence]

From my 17 SS1LE that I owned for 4 years (~22k miles) in FL I have a theory that the cold running temps of the TR6060 degrades the shifting feel. If I wasn't on the track the trans fluid never got that hot, so im assuming that some amount of moisture was retained in the fluid over time.

..Anyhow theory aside, I never had an issue with the OEM fluid until some time got on it, then there was a noticeable improvement moving to Redline D4. The trans also liked the D4 better when hot (Doing a track day it was less finicky). Though with time D4 also started feeling meh in the shift feel. Drain and fill with Fresh D4 fixed that.

Fresh to Fresh fluid no one notices anything, "old" fluid to fresh regardless of flavor people feel an improvement.

I just think the TR6060 just needs fresh fluid to feel good.

Interesting. Thanks for sharing your experience. I got some Amsoil Torque Drive and plan on swapping it in there this weekend. Even though I only have 10k miles on my car so my fluid isn't old, I figure it can't hurt, and I've read nothing but good things on Vette forums about it in these trannies.

 

[Overfill]

I would go with an MTF instead of an ATF, since MTFs have the correct friction modifiers for synchros.

 

[thastinger]

I have one in a 13 GT500, Royal Purple Synchromax cured the second gear notchy shift. I didn't tell the Wife I changed out the fluid in it, she took it out and texted me "what did you do to fix the transmission in Shelby"

 

[slacktide_bitog]

Welcome to BITOG

Some people like synchromesh fluids in these, such as RP Synchromax, Pennzoil Synchromesh, Valvoline Synchromesh, or GM Synchromesh

GM still makes a Dexron III-based fluid for manual transmissions. Part number 88861800.

 

[nascarnation]

Maybe this would be a good use case for some TES-295 (Delvac 1 ATF) or TranSynd? DEX III viscosity and synthetic. I like to think of it as all the good from DEX V.I. with the III viscosity.

Amen brother!