Tremec 3650, I need advice!

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Nov 6, 2010
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Hello all. I am going to be swapping out the clutch in my 02 Mustang GT here in a weekend or two (throwout bearing started squealin' like a pig). I figured that while I had it out, I may as well swap the fluid in the tranny. I doubt that it has ever been changed, and it is very notchy. I have probably spent a good 3 or 4 hours reading threads all over the internet about this particular transmission. I am still confused. Do I put in ATF, if so, Dex III? synthetic, or non-syn? Synchromesh? If so, Pennzoil, GM, Amsoil, RP? I've read all sorts of conflicting reports. I tried today to contact Tremec and see what they recommend, but I couldn't get anyone to answer. What have you had good luck with, or if you've talked to Tremec, what do they recommend? Thanks in advance for your help!
 
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Yes, some manual transmissions are spec'd to run ATF in their cases. My own ram is one of those cases. Another common case is dumping that trash for a good gear oil instead. I use Amsoil.
 
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Originally Posted By: DoubleWasp
Yes, some manual transmissions are spec'd to run ATF in their cases. My own ram is one of those cases. Another common case is dumping that trash for a good gear oil instead. I use Amsoil.
Learn something new each day. Haven't driven a standered in 20 or so years. After highschool suffered a knee ingury. The constant changing gears clutch, etc was killing me. To much in city drive at the time. Its not bad on the highway but bumper to bumper was killing me. Not only that but people litterly inches from your bumper on a incline..
 
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Originally Posted By: DoubleWasp
Yes, some most manual transmissions are spec'd to run ATF in their cases.
Fixed that up a little. GL4 and higher gear lubes are incompatible with most synchronizers, so ATF has been the more common fill fluid since the mid/late 90s. Some manufacturers were already using it in the 60s and 70s. For older gearboxes that want a heavier oil than ATF like a 90-weight gear oil, either a heavy manual trans lube like Redline MT-90 or a 40-weight(*) engine oil is the most common substitution *- engine and gear oil SAE viscosities aren't on the same scale. A the allowable viscosity range for a 90-weight gear oil overlaps with that of a 40-weight engine oil.
 
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I was talking to an engineer with Tremec a few years back,and he said to only use ATF in them. He said it's because of the needle bearings and the fiber synchros they use.
 
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Yah, the Rat has a 5 spd, an M5od. I think its a Mitsubishi,uses Mercon It is my first manual since my Willys died in the early '90s. It had a T90 3 spd and everything in back of the engine took 90 weight
 
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I just replaced the clutch assembly in a 92 mustang gt. we used Dex III; personally I would use synthetic, but it was my buddy's car, and he only wanted to pay for dino. while you're there, replace the flywheel and also the rear main seal.
 
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Its a much newer transmission, but the current Viper, Challenger, Camaro, and at least one version of the Mustang all use variants of the Tremec TR-6060. The owners' manuals for each car recommend the parent company's fluid (Challenger and Viper- ATF +4, Camaro- Dexron VI, Ford- whatever Mercon Ford uses these days). The enthusiast forums have constant threads about what fluid is actually "the best" for the Tremec and one thing keeps coming up- when people call Tremec directly, they seem to always be told that Mobil 1 Synthetic ATF is great but that warranty coverage will be left up to Ford, GM, or Chrysler and that's why each insists on its own fluid. Anecdotally, people have used RP Synchromax and Redline MTL without issues, and often with better 2nd gear engagement (reduces the "Tremec Nibble").
 
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They don't, and GM sells rebottled Dexron III (p/n 88861800) for these applications. I'm not sure why Dex 6 isn't recommended, because Dex3 shears down to Dex6 viscosity or less pretty quickly anyway, but there's probably a reason. In Australia Castrol Transmax Z is a popular choice for the Tremecs that spec ATF, it's the same as Transynd as far as I can tell. Any of the TES295 Transynd clones would be a good choice, they're shear stable and a bit thicker at 100 degC than most multi-app synthetics. Maxlife is very thin.
 
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Having run that tranny and others in its family I can say with all honestly that the maxlife dex/merc fluid worked just great in every t-5/t-45/t-3650 I used it in. Amsoil synchromesh is nice too if you don't mind spending more.
 
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I had both 01 and 03 GTs. Also had an 05 and 09. I spoke with Tremec about the fluid for my 03's tranny when I came across a document that recommended a Havoline ATF. Long story short, they recommended Mobil 1 synthetic ATF, and that's what I ran in my Stangs. Never had an issue. YMMV
 
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I ran Redline D4 in my '03 Mach 1 and had no issues, it was actually an improvement over the dino Mercon V that was in there before.
 
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Originally Posted By: panthermike
I ran Redline D4 in my '03 Mach 1 and had no issues, it was actually an improvement over the dino Mercon V that was in there before.
My T56 actually shifted the BEST with this stuff in it, BUT, everyone on here swears up and down that it just cannot protect the gears and bearings as well as any thin(ner) MTL, despite their lead tech/tribologist Dave (and his company) claiming the D4 DOES have GL-4 levels of gear/bearing protection. shrug
 
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Originally Posted By: dailydriver
My T56 actually shifted the BEST with this stuff in it, BUT, everyone on here swears up and down that it just cannot protect the gears and bearings as well as any thin(ner) MTL, despite their lead tech/tribologist Dave (and his company) claiming the D4 DOES have GL-4 levels of gear/bearing protection. shrug
The T56 in my Commodore shifts great on synth ATF, they don't like thicker oil especially in cold climates. These Tremecs rarely suffer lubrication-related failures even when running on cheap Dexron III ditchwater. Tremec designed them to run just fine without GL4 protection and they seem to have got it right. Most problems with them are people beating up synchros, or catastrophic failures when drastically overpowered, neither of which can be fixed with better oils. On the Aussie forums, a $70/litre oil is popular to address this non-existant problem, and sells based on "testing" with no control. It's funny to watch the kool-aid drinkers dance around the cold shifting issues that this 75w-80 causes. It's probably a good oil for circuit racing applications, but the price is stupid even by Australian standards. A heavy duty ATF like D4, Amsoil or Transynd will work well if you want extra protection. GM Synchromesh seems to be a safe choice too, if you don't live in a cold climate.
 
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Originally Posted By: undertow
Originally Posted By: dailydriver
My T56 actually shifted the BEST with this stuff in it, BUT, everyone on here swears up and down that it just cannot protect the gears and bearings as well as any thin(ner) MTL, despite their lead tech/tribologist Dave (and his company) claiming the D4 DOES have GL-4 levels of gear/bearing protection. shrug
The T56 in my Commodore shifts great on synth ATF, they don't like thicker oil especially in cold climates. These Tremecs rarely suffer lubrication-related failures even when running on cheap Dexron III ditchwater. Tremec designed them to run just fine without GL4 protection and they seem to have got it right. Most problems with them are people beating up synchros, or catastrophic failures when drastically overpowered, neither of which can be fixed with better oils. On the Aussie forums, a $70/litre oil is popular to address this non-existant problem, and sells based on "testing" with no control. It's funny to watch the kool-aid drinkers dance around the cold shifting issues that this 75w-80 causes. It's probably a good oil for circuit racing applications, but the price is stupid even by Australian standards. A heavy duty ATF like D4, Amsoil or Transynd will work well if you want extra protection. GM Synchromesh seems to be a safe choice too, if you don't live in a cold climate.
The Amsoil MTF is one of the thinnest of the non-Euro, FULL synthetic manual trans fluids, and I was going to try it this change (to get the very poor shifting, but proper viscosity, thin, Ravenol out of there). But I think I am going to just use the D4, as a national champion autocrosser has used it in his VERY high mile (~300K now), beat on, open tracked as well, daily driven, E/Street Prepared Z28's T56 since new, and has NEVER had a problem, or rebuilt the thing yet. wink (It's almost $5.00/quart LESS than most of the good, synthetic, MTLs/MTFs out there as well! thumbsup )
 
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