Transmission Fluid

[JacksAO]

What are you guy's using for transmission fluid in a 1985 GT 5 speed? Owners manual calls for Dextron 3 and I've been using B&M trick shift in it which made a huge improvement in how it shifted. Just what to know if there's anything out there that's "new & improved"

[Basin Motorsports]

I have AMSOIL ATF fluid in mine which covers the Dexron series.

[KevinK]

Some swear by using Redline atf

[dynodon64]

The recommended fluids for the non world class transmission now is just straight 30 weight motor oil. If it's a world class than regular ATF for Fords is used.

[mmb617]

I always used the parts store house brand Dexron III/Mercon ATF. I honestly don't think it makes much difference with a manual transmission. Probably any ATF would be fine. I never noticed any problems with the way mine shifts.

[homer302]

Redline is good. I have used it more than any other probably. GM Syncromesh is probably the most widely used. That's actually what's in mine at this point. If you are just driving around and not abusing it as MMB says, parts store brand ATF will be fine. Let's face it, NAPA (or Autozone, Advance etc) does not have an oil refinery somewhere. It's all major name brand with a different sticker on it. There's only so many places that make ATF.

[erratic50]

The T5 transmission that I've had that has lasted the longest was ran on pure DextronII ATF. It made it over 200K miles with ME beating on it. LOL. It was a unit from D&D rated at 315 ft lbs. 1352-199 with D&D carbon fiber updates. Stock shifter. Occasionally ran with sticky tires. ($1000 special from D&D in 1999)

The 2nd longest was ran on pure DextronII ATF from the same case. Made it 150K miles with me beating on it and doing a ton of racing, etc. It was a 1352-199 Ford WC replacement trans. Stock shifter. Always ran with VERY sticky tires. (bought in 1992, $1795 trans straight from Ford parts counter. OUCH)

The T5 transmission that I've had that lasted the least amount of time was ran on pure DextronII ATF from the same case of tranny fluid (still have it years later) Nothing awesome for tires were ever ran. It made it around 10K miles with me beating on it. it was also a 1352-199 and was an identical twin to the one that lasted 150K miles even though I never did anything particularly bad to this trans. it scattered itself on an easy 1-2 shift at 2000 RPM for heavens sake. I ran a Hurst competition plus shifter with positive stops adjusted properly ..... (bought in 2009 on a poorly listed ebay auction. Was still new in box and a twin to the $1795 trans.... score! Or so I thought at the time.... still made money when I sold the core for $125 buyer pays shipping. LOL)

Anyway -- I could cover some of the other units I've absolutely destroyed that fell somewhere in between these extremes. It was the same damn car, same fluid, same everything.

A few of the transmission guys I've talked to said you will get better results breaking in a fresh set of synchros with lesser lubricants and NEVER EVER run teflon based additives in a stock synchro WCT5 because it compromises the synchros after just a little while then teeth start getting tore up. i think that's what was causing my 150K mile 1352-199 to go downhill, but it was a cheap pilot bearing I installed during a clutch job where I was fixing stuff just to "do it right" (damn it) that did it in catastrophically.

Put your money on the table, and give the dice a throw. That's about how it goes.

What you get from your transmission in the long run depends upon a lot of factors. Things like broken brackets or bad mounts, cheap clutches, worn U-joints, wheel hop, etc, all nearly guarantee an early exit yet sometimes you can have all of those and have the transmissions die of stupid crap like literally worn out teeth on the input shaft. (like my 200K unit did....)

From now on, I personally plan to put my money on better parts and listening to the guys to made those better parts. When I think about all the time and money I've wasted on blowing out T5's I don't think I'll ever run anything near stock ever again.

I have a T5Z in my son's 86GT and a T5Z in my 86GT also. They are a better transmission it seems, but time will tell.

My 85 build is getting a Gforce build with a bunch stuff work done to add as much strength as possible while still running a production case.

Speaking of that -- what does Tremec, GForce, and Astro have to say about it?