For transmission and diff fluid, what would you FC guys run? I've heard that you shouldn't use Mobil 1 in our gearboxes because it isn't nice to our synchros, Redline is mostly for track drivers who like to smash into gear as quick as possible, Neo is butter smooth, so is Amsoil, Royal Purple doesn't have any outstanding characteristics, and Motul... Well, nobody ever mentions it over here in the 2nd Gen section.

I've got a T2 and the synchro gears are pretty worn. It's almost bone stock and mostly a street car. So based on what I've read so far, Neo and Amsoil would be my safest bets for the gearbox, but Royal Purple is fine if I need to hop down to Autozone for an extra quart. Diff seems to be fair game for any fluid... Sounds about right?

 

check your fsm or a haynes manual it will say specifically what to use. as for me i use ROYAL PURPLE 75w90. i believe the fsm or haynes says to use 80w90. trans and diff fluid is the same i believe.

 

I'm not a big fan of Mobil, but otherwise any major-brand synthetic oil will work fine. In general, Group V base stock is better for heat and shock resistance, while Group IV is more slick and smooth, but the difference is not very significant nowadays. For a street car I would just go with whatever is easier or cheaper to obtain.

 

How about for spirited driving and weekend track days?

 

redline shockproof heavyweight!
i use it on the street and on the track! Helped me ALOT and i have no disadvantages at all, i dis hear of ppl having problems when cold but i dont drive that car during winter

 

Redline baby. FC3Spro has an article on his page which links to the summit page to purchase. It is not exactly cheap anymore But I love the feel of my transmission and differential with it.

 

I'll cast my vote for Royal Purple if only because it what is in my gearbox and I can get it locally. Actually my 3rd gear synchro is flakey and I had Mobil1 in it years ago. When I switched to Royal Purple there was a noticeable improvement with 3rd. I think if I hadn't switched I would have hade to replace it by now. This was 10 years ago and it was pretty bad. Only trouble I have now is I have to double clutch on downshifts to 3rd or it grinds. Before I switched IIRC it always ground 3rd double clutch or not. I do have Redline in the diff but it was given to me by someone who was getting out of Rx7's. Probably switch to Royal Purple in it eventually.

 

Is redline shockproof really worth it for a street car though? I'm concerned that it's mostly for heavy driving and not as kindly to the synchros long term, which I just had replaced and got the gearbox back today. That's why I wouldnt touch Mobil 1 with a stick.

Dak, so you've been running royal purple for 10 years? No trouble with the synchros?

Also, has anyone used Lucas?

 

Im pretty certain lucas is blasphemous around here or any of the autozone type oils LOL. I urge you to stay away from autozone goop.

 

.... Well then.

This never happened.

 

I am all against amsoil and lucas. Good if you want something quiet to get it sold. Not very good at lubrication. Ive replaced several motors in customers cars who swear by such oils. A boxer motor has about 40k of life with amsoil... And amsoil pays for the motor every time. I sure as hell wouldnt put that crap in anything I owned

 

Synthetics may help your shifts, but if the syncros are worn, it won't fix them

I run NEO in my FD and love it. Wish i put it in earlier. Shifting is much smoother, but i do get the occasional clunk for the worn syncro

 

I've tried Redline MTL and MT-90 and find it a bit notchy when cold. I'm going to try NEO next time, whenever that may be.

 

Somewhere there about. It could have only been7 or 8. I just know I changed it where I live now and I've been here 10 years. Please nobody get too upset but I haven't changed it since so that fluid's probably got a good 150k miles on it or more so I'm due another change. Only trouble is down shifting to 3rd as previously mentioned and it is still better than when the Mobil1 was in there. If I redline 2nd going into 3rd feels different than the other gears but doesn't grind if I don't force it too fast. Going into 3rd has always felt different ever since I owned the car. Had approx. 83k when I got it. Also some times it will not want go into 1st gear when I first start the car but this is seldom like once every month or two. I don't think that's synchro related. This gearbox has 274,xxx miles on it though.

 

I run a quart of syncromesh and fill the rest with 80/90 in the trans.

 

Royal Purple ftw

 

Ordered the NEO and am not looking back. If my transmission and differential blows up, then I'll report back. Otherwise, I think I'll let this dead horse rest in peace for once.