What is the best kind of fluid i should put in my t-5 speed trans?

[cobracomander]

What is the best kind of fluid i should put in my t-5 speed trans?
going to install it this weekend I need to know what fluid I should fill it with?
thanks!

[Zap's 85 GT]

Is it a world class or non world class T-5?

[FM2NOTCH]

what year is the trans? pre 85 is non world class, 85 up was world class and use ATF, there is some debate on what the NWC's used, some say heavy gear lube, others say ATF. If you use ATF I'd go with mobile 1 synthetic ATF

http://www.moderndriveline.com/Techn...t5_history.htm

TREMEC now recommend using straight 50w gear oil in NWC, The lighter Dextron III (ATF) can be used but may effect shifting and wear.

"One last piece of important information. ALL World Class T-5 use ATF (Dextron III) oil and NOT heavy gear oil or Redline MTL!

All NON-World Class T-5 use 50 wt gear oil. (The original Ford/Borg-Warner recommendation back in 1984 was Dextron II. As this is no longer available, we and TREMEC recommend the 50 wt gear oil.) We recommend high quality Synthetic oil as it lasts a long time and over a larger operating temperature."

[cobracomander]

It came out of a 86 gt date code says 86. So its a WC t-5
How much does take to fill it?

[1986Saleen]

2.75 quarts

[FoxChassis]

what year is the trans? pre 85 is non world class, 85 up was world class and use ATF, there is some debate on what the NWC's used, some say heavy gear lube, others say ATF. If you use ATF I'd go with mobile 1 synthetic ATF

http://www.moderndriveline.com/Techn...t5_history.htm

TREMEC now recommend using straight 50w gear oil in NWC, The lighter Dextron III (ATF) can be used but may effect shifting and wear.

"One last piece of important information. ALL World Class T-5 use ATF (Dextron III) oil and NOT heavy gear oil or Redline MTL!

All NON-World Class T-5 use 50 wt gear oil. (The original Ford/Borg-Warner recommendation back in 1984 was Dextron II. As this is no longer available, we and TREMEC recommend the 50 wt gear oil.) We recommend high quality Synthetic oil as it lasts a long time and over a larger operating temperature."

The current recommendation from TREMEC is 30W motor oil, not 50W gear oil.

[FM2NOTCH]

evidently Bruce Couture owner of Moderndriveline.com is so busy doing T5 and 6 speed conversions he hasn't had time to listen or read Tremec's recommendations

http://www.moderndriveline.com/
Phone number 208-453-9800

[FoxChassis]

Borg Warner (and Tremec after they purchased BW in 2008) specifically stated in their service manual that NWC was not to be serviced with gear oil, and that you should refer to the vehicle manufacturer for fluid recommendation. Ford specially stated in their owner guides and service manuals that Dexron II was the fluid to be used for NCW.

Stan Peace or Pro-Force Performance.com (an SEFB sponsor) and I went back and forth on this subject at AFM back in late 2009.

http://www.allfordmustangs.com/forum...nsmission.html

Be sure to read the response from Paul Cangialosi (of www.5speeds.com) on page 2 of that thread.

And Stan's post about the whole gear oil myth on SEFB: http://sefb.net/forums/showthread.ph...TED-01-09-2012

Modern Driveline had for years (until early 2011) stated that NWC used 70wt gear oil. No mention of Dexron II or any other ATF whatsoever. That was wrong then and is wrong now.

Stan's website on the T-5 history states this about fluid for the NWC:

http://www.pro-forceperformance.com/t-5_history.htm

Transmission Fluid

BorgWarner allowed each manufacturer to choose the lubricant for its particular application, but it seems that BorgWarner's recommendation was Dexron-II ATF from the very beginning. GM adopted the Dexron, as proven by the stickers placed on each transmission. Ford adopted Dexron as their official fluid, as proven by specifying the ATF product in their original 1983 and 1984 Field Service Manual publications. For some reason, AMC chose to continue specifying gear oil instead of ATF. The early style of Dexron is no longer available. Generic ATF such as DEX/MERC is a suitable substitute. A Ford dealer will recommend their Mercon-V ATF which is also a good substitute.

Many Internet sources insist that gear oil should be used in the Non-World Class T-5, but the documentation above clearly reveals that both Ford and GM chose to use ATF from the start. Using gear oil in a Non-World Class transmission will not significantly damage the transmission, but many times, due to Internet confusion as to what is, and is not, a World Class T-5, gear oil has been mistakenly used in the World Class units.


Update on Dexron VS Gear oil for NON-World Class T-5's:

Dexron-III ATF replaced Dexron-II in 1993. While Dexron-III meets or exceeds the previous specifications, the viscocity of Dexron-III is thinner than the original Dexron-II that was specified for the NON-World Class T-5. This thinner fluid is fine for the World Class T-5 with the lined synchro rings, but the NON-World Class T-5 with the brass synchro rings needs a thicker fluid to work optimally. As a result, Tremec has specified 30W MOTOR OIL for the NON-World Class T-5's. While Tremec has not published an official document about this, it is confirmed by an email dated 1/9/2012 from a Tremec Engineering/Support employee.

[Ourobos]

That sums it up nicely..

Back to your question, on an WC in 1986, you'd be even happier with Pennzoil Synchromesh, it's a little better alternative to the conventional fluids.

[FM2NOTCH]

I guess the debate will continue until it's made official, believe the man who installs transmissions for a living or a email from a tremec employee

"While Tremec has not published an official document about this, it is confirmed by an email dated 1/9/2012 from a Tremec Engineering/Support employee"

[grabbergreen84]

I guess the debate will continue until it's made official, believe the man who installs transmissions for a living or a email from a tremec employee

"While Tremec has not published an official document about this, it is confirmed by an email dated 1/9/2012 from a Tremec Engineering/Support employee"

One of my friends has a transmission shop, and his recommendation was always to run half gear oil and the other half automatic transmission fluid. (He never addressed WC vs. non WC, however.) He thinks they work and shift the best with this mixture - though, it's been like 10 or 15 years since I heard him talk about this issue. He's a Camaro guy, who picked up and has held onto a black '85 Capri RS 5.0 4V.

[JACook]

'85 Camaro used the NWC box with the brass blocker rings... FWIW.

[FM2NOTCH]

One of my friends has a transmission shop, and his recommendation was always to run half gear oil and the other half automatic transmission fluid. (He never addressed WC vs. non WC, however.) He thinks they work and shift the best with this mixture - though, it's been like 10 or 15 years since I heard him talk about this issue. He's a Camaro guy, who picked up and has held onto a black '85 RS 5.0 4V.

well there you go, the best of both 1/2 gear oil and 1/2 ATF

edit: don't do this in a WC T5, the sulfer content will harm the fiber lined blocker rings

[FM2NOTCH]

That sums it up nicely..

Back to your question, on an WC in 1986, you'd be even happier with Pennzoil Synchromesh, it's a little better alternative to the conventional fluids.

after drag racing my 85(for approx 3 years) with the stock T5 with mobile 1 synthethic, I switched to GM synchromesh and busted the trans the same night.

coincidence? maybe, maybe not

[grabbergreen84]

'85 Camaro used the NWC box with the brass blocker rings... FWIW.

An '85 Capri RS 5.0 4V.
His Camaros are second gens with turbo 350s.

[Capriman86]

That sums it up nicely..

Back to your question, on an WC in 1986, you'd be even happier with Pennzoil Synchromesh, it's a little better alternative to the conventional fluids.

This is what I have used as well too, well I used GM Synchromesh, but it did worked good.

[bwguardian]

I use ATF with 1/2 quart oil...been using it for years in both WC and non WC with no problems.

[mmb617]

Everybody has their preferences, and I don't profess to know what's best. All I can say is I use the Autozone house brand Dex/Merc in my WCT5 and it works fine for me. But then it gets changed each time the transmission breaks which averages about once a year. I don't blame the failures on the fluid though but rather on the racing 100+ passes a year behind my 408. The transmission shifts real nice and when it breaks I just replace the broken parts. I've never noticed any unusual wear on the unbroken parts. I have heard that synthetic fluids can be too slippery to allow the synchros to stop the gears spinning properly, but can't say if that's the case as I've never used any synthetics. As well as the cheap ATF works in my much abused T5 it's hard for me to imagine you could go wrong with any ATF for street use. More expensive fluid isn't always going to be better. This is just my opinion, feel free to differ!

[grabbergreen84]

Everybody has their preferences, and I don't profess to know what's best. All I can say is I use the Autozone house brand Dex/Merc in my WCT5 and it works fine for me. But then it gets changed each time the transmission breaks which averages about once a year. I don't blame the failures on the fluid though but rather on the racing 100+ passes a year behind my 408. The transmission shifts real nice and when it breaks I just replace the broken parts. I've never noticed any unusual wear on the unbroken parts. I have heard that synthetic fluids can be too slippery to allow the synchros to stop the gears spinning properly, but can't say if that's the case as I've never used any synthetics. As well as the cheap ATF works in my much abused T5 it's hard for me to imagine you could go wrong with any ATF for street use. More expensive fluid isn't always going to be better. This is just my opinion, feel free to differ!

Can you look your Mustang in the eye, and tell it that?

[FM2NOTCH]

ok I'm making it semi official

pre 1985 NWC T5 "can" use engine oil or ATF

1985 and up WC T5, use ATF only to prevent damage to fiber lined blocker rings, do "not" use gear lube or engine oil or any additive that might contain sulfer

I personally don't recommend anything with the word "synchromesh" in a WC T5

[Zap's 85 GT]

Not that I'm biased or anything.

http://www.mustangandfords.com/techa...n_maintenance/

[FoxChassis]

That article says 10W30, which is not the same as 30W. The former is a mutil-viscosity oil (10W when cold, 30W when at operating temp), the latter is a straight 30W at all temps.

[LilRed86coupe]

This is the only manual trans fluid i'll ever use because it just flat out works great in all the T-5's and Tremec's i've put it in.

http://www.amsoil.com/shop/by-produc...?code=MTFQT-EA

[FM2NOTCH]

This is the only manual trans fluid i'll ever use because it just flat out works great in all the T-5's and Tremec's i've put it in.

http://www.amsoil.com/shop/by-produc...?code=MTFQT-EA

from the article "and is compatible with brass synchros for smooth synchromesh shift quality"

no mention of fiber lined T5 blocker rings so I'm not sure it's the best for the WC T5

[LilRed86coupe]

from the article "and is compatible with brass synchros for smooth synchromesh shift quality"

no mention of fiber lined T5 blocker rings so I'm not sure it's the best for the WC T5

It must work because i've got over 300 powershift's on a stock rebuilt 1990 T-5 in one of my brothers weekend toys we race. Its behind a 351w no less that runs 11.20's N/A and probably has 20k street miles also. Its been in my 2007 GT since new and it now has over 85k miles with over 100 poweshift's. The Amsoil rep i buy my oil from says that Tremec recommends this oil in all there transmissions including the WC T-5 they produce.