I wouldn't call it more thorough. Shep has a high strength gear set while TRE shotpeens and hones the stock gears to get the most out of them. I think that TRE's work is great, but he can be hard to reach.

 

So i haven't updated this in awhile! I know i posted before that last year i was going to go with a TRE 6 speed trans over the winter but i decided to see when mine would break.

I also picked up a spare 6 speed, hoping it was in better condition than my current, but come to find out that the used (supposedly 55k miles, never beat on) trans has a 4th gear grind, that is pretty bad, but still goes into gear. And after all the work of installing it, i left it in.

Now for the first 10k miles with this newer/used trans, i ran AMSOIL mtg 75w90, and it ran just like the old trans, plus a 4th gear grind. Now as of last month, i changed all my fluids but decided to run Motul 300 75w90 (not to be confused with "Motul 300LS"), and WOW what a difference. I still had the 4th grind here and there but not nearly as bad as it was with AMSOIL. and the more i drive it, the better it seems to get.

Just to refresh everyone on my build, I'm making 470whp and over 400wtq with an FP Red, built motor revving to 8.5k, and an Exedy twin disk to hold it all. A few days after the fluid change i went to the drag strip and ran 3 passes. My best of 12.08 at 115, (i know i can't drive lol) but i still beat this trans pretty hard, my best 60' was 1.7.

I will try and continue to update with my findings with this trans as much as possible! but for daily driver and a few launches, i doubt a Trans cooler is required, i don't think you need one for drag racing either. But i HIGHLY recommend "Motul 300 75w90" fluid for the 6 speed MR trans. I plan on running this trans into the ground. Between trying for low 11 second passes at the strip to 200 miles a week daily driving. We'll see where it goes!

 

Hell yah. Same here. but i'll continue to use OEM fluid only.

 

I'm curious how it holds up with the motul. I know various shops including JACKS and TRE have said the 6spd doesn't like anything but diaqueen inside so I'm really curious to see how you make out with the Motul 300 oil. Would be nice to have other options

 

I'd be a bit cautious of improved shifting. To me that suggests less lubricity. Suggest you try to find out what modifiers are in the oil to prevent metal-to-metal contact under high load.

 

I've read somewhere on TRE's site that he likes the Motul 300, but not sure which Trans he was talking about. Same with the Amsoil. It is a little concerning about the the better shifting and possibly being bad for the trans but, I launched it last night with no issues, spun all 4 tires through first gear. And even today it feels as though it drives better.
Actually, 4th gear didn't grind once on my way to work today (25 miles one way) even when I was really slamming gears. Also when shifting slow, I didn't have to baby it into 4th. It just doesn't grind now. So weird.

 

But we'll see how long it goes. I won't be in town from next Monday until Labor Day, and I can't make it to Import Face off in Pittsburgh this weekend, so it'll sit. I'm hoping to really push it hard at the strip before the season is over.

 

most shops i've seen recommend only OEM fluids in the 6spd, the 5spd can use other stuff, from the looks of it.

 

Been over 400whp on stock 6 speed with oem fluids for over 40k miles. No issues at all. Currently at 500/390.

Beat on it daily, but don't abuse it if that makes sense.

 

Thought I heard the 5speed have thicker gears, and if u mis-shift on a 6sp it tends to destroy the tranny and the bushings so it will slip.

 

Correct. 3rd and 4th gears were "thinned" to make room for 6th gear since the 5spd and 6spd transmissions use the same housing. That means the 6spd has weaker gears and the oil capacity is smaller meaning the heat is not properly addressed and these puppies will grenade because of it.

It's all 100% on how you drive it. If you like to dump the clutch and slam gears, well guess what, she's not gonna last. If you respect the tranny and do regular fluid changes, it will last a long time.

 

Aren't there some key differences between the cases such as shaft spacing?

 

1st + 2nd are actually wider on the 6 speed than the 5 speed.

https://www.evolutionm.net/forums/ev...ml#post3437271

 

I'm sure the similarities end at the external housing and even then there are slight differences. The internals must be very different.

 

Wow it's worse than I thought. 3rd and onward were made smaller