Yup. Common knowledge for a while now. Along with less fluid, it's why the gears can fail.

Pretty interesting stuff^ if it makes a difference to anyone following my experimenting with it, when I fill my Mr trans with Motul, I put about 2.5-2.6 quarts in. And let drip until I had time to hurry and put the fill plug back in. So I know it's more than the 2.3 that the manual says to have.

Great thread.

I recently bought a fairly stock IX MR with 36k on it. Already did one track day (pretty much all fourth gear) and plan on going e85 next spring. Looks like I'll be doing a trans oil cooler over the winter.

I'm very interested to see your Trans cooler build!^^^ it's not worth it on my build. But I bet it'll do great for you at the track

Mine EVO IX GSR is around 400hp with 6-speed gearbox and never had any trouble. Obviously I service my car when required and check it sometimes to see if everything is still ok.

so far, so good? a few trans places swear to use nothing but OEM fluids in the 6spd.

I've been running Motul for about 2-3k miles now. And it got rid of my 4th gear grind and shift way better too. I've ran Pennzoil Syncronesh, which is horrible. It's a quick way to ruin your trans. OEM was alright, can't go wrong. Amsoil MTG was good, I ran that the most. But Recently I switched to Motul 300- 75w90 and it's like magical how nice my trans is now. And no grinds now either. So for now, Motul had my vote!

good luck, dude. it would be nice to have an alternative. we'll have to see how the Motul lasts in the long run.
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It'll be nice if it holds! I had all these plans to take stuff apart this winter but since my 6 speed isn't broken I don't have a reason too. I plan on a lot of drag racing in the future, trying for a low 11 on 93 octane, then possibly 10's on e85 next year, all with a 6 speed.

My OEM 6 speed always ground 2nd gear. Annoyed the **** outta me, so at 12,000 miles I threw in some SynTorq LT by Castrol. It's a 75W-85 just like OEM and it did wonders for the car, but it required more frequent transmission fluid changes to keep it feeling "good." Got 175,000 miles on the old 6 speed, no issues and no grinding with around 330whp on an MD.

The cases for the 5 speed and 6 speed are completely different. They obviously have to live in the same space, so dimensionally they're the same. But the 6 speed case has cooling fins on it and it's made by AISIN....not sure who makes/made the 5 speed, but it was a different vendor IIRC.

THe reason I liked the SynTorq LT is because it was a low temperature formulation for the NV4500 transmissions, since they were susceptible to heat problems...one of the issues that plagues the 6 speed with only 2.3 liters of fluid in it compared to 3 on the 5 speed. You can't get SYnTorq LT in the states, but it's actually the factory fill for Dodge Vipers. You can get it at any Dodge dealer.

I haven't driven my new Shep 6 speed, but you know that I am itching to whenever my build gets done :)

So cool! I may give that a try if the Motul doesn't work out! I wish I had the money for the shep one. I've tried contacting TRE but like everyone else says, it seems, he is hard to get ahold of.

Def interested to see how your shep holds up, and good info too. Also, Instead of 2.3 quarts, I put about 2.5-2.7 in. I also fill my trans when it's on a slant (jack stands up front, rear on the ground.) and that's about how much fluid I get in before it starts slowly spilling out of the fill plug. So the extra fluid may be helping, I haven't seen any negative effects of that yet.

Jackstands are a good little trick. I'll have to do that when we fill her up. Besides getting all the gears REM Isofinished, I had everything WPC treated as well...gears, input shafts, sliders...everything. Gives me a little added insurance against things going south on E85 :cool:

That's awesome, you are not sparing anything it seems. I'm sure that trans will treat you well. It would be cool to see the fastest 6 speed record!

Yeah. I'm calling this the "Big Hole in My Wallet Build."

And I don't want to set any records. Ok, hp per level of boost might be nice (on a Red), but I think the car will be plenty fast enough for me as is :D

And your running a red! Now I'm really interested. I have a Red too, love this turbo