I got a S4C from a local guy, thinking from a SiR? vin is EM1. Was recently rebuilt by Acura ~10k ago and had a brand new LSD installed along with an LS 5th as it was originally open.

I would like to think that someone doing this would've probably not bothered with a viscous? I'm sure he probably told me but this was like over a year ago.

I took some pics inside the axle shaft holes I can post.

I'm about to put it in a 93 GS-R which currently has a cable YS-1. I mostly got the transmission because I wanted LSD.

Didn't think the cable/hydro was going to be such a pain but for now I'm going with the Innovate cable adapter while I work on fabbing up a pedal set for hydro ('lude pedal welded to mine should work). I was also considering a case swap but didn't want to end up with a hydro case with YS1 internals left over, I'd rather have a fully original YS1 left over.

Don't want to bother cracking the trans, it's going in right away.

Tried spinning it a bit, both sides spin even when I hold one side but I can't really put a lot of torque on it without an axle to stick in there..I would thing viscous would be easier to hold one side..?

 

Take a good, clear, well lit picture of the differential through the axle seal, with both axles removed.

 

weird I swear I posted the pics






hope those are good enough thanks

 

Looks like an OEM viscous. OEM helical doesn't use the 6208 diff bearing, but they could have used the 6208's with a spacer underneath.

 

So no real way to know for sure though viscous would be your guess. I'll have to maybe ask the guy. Since it's rebuilt I'd guess it could go either way.

I guess I'll have to see once it's in the car maybe? Going in either way!

In your opinion, since I know you're an expert (thanks for responding btw), how would you compare the two OEM units?

From what I've read the helical is the better option by far.. which makes me wonder why someone would put a viscous in when paying for a full rebuild?

There seems to be only certain types depending on the number of bolts (10/14) - would there be a way to know what my trans should be as far as that is and then deduct the possible LSD?

This will be for a daily driven (hard) car that might see light a/c or track use..I run Proxes RA-1's in the summer.

currently stock B17A1 but will be boosting shortly, but probably keeping the turbo smaller on this one than my EG b17a1 (already have the turbo).

 

I didn't even notice the number in the 2nd to last pic, I was thinking that pic was going to be useless too! Guess it wasn't?

 

P.O. said (man its a pain to go searching for crap over a year old on fb):

So, "identical to ITR" should mean it's helical, all ITR came with helical right?

 

So he couldn't say for certain whether it was viscous or helical but he is certain it's a ITR diff.. so based on that it should be helical? and perhaps they did what you said with spacer?

Guess I won't know 100% until I stick some axles in it and spin eh? (or unless I crack the case..which again I just don't feel like sealing it up again when I'm like RIGHT about to throw it in either way, LSD > open regardless, obviously would be happier if it was helical / slightly annoyed if it wasn't as it was claimed to be an ITR diff from before sale)

 

Is it true that only viscous came in JDMs? he seems to think that the only part # avail in N/A would've been the ITR diff.

Seems convinced it's the ITR diff so, should be helical.

 

Hey, aquafina, I saw this that you posted in an old thread:

How high RPM would you consider? B17A1 is 8000 redline and 8250 fuel cut stock, which is what I'm running. I've already got Honda MTF as it's what I've always used and always seen recommended by most Honda guys and that it is just basically dino 10w-30 anyway, so I'm curious about that..? So I search and see you saying:

Seems like you rebuild these things all day everyday right..? I've surprisingly never really seen this opinion before; the car is mostly street driven and I drive pretty hard (VTEC yo? but seriously my engine's peak power is 7600, peak torque is 7400..kinda gotta rev it up) but always rev match shifts, often half double clutching to sync shafts (I break load off the gears by slightly lifting on the pedal, in to neutral instead of the first clutch in a double clutch, then tap clutch in a bit when RPMs are sync'd and into gear)

I assume Honda MTF is in the YS1 currently as it was Acura serviced. I have no idea how old it is, I was planning on doing a change with the Honda MTF but figured I'd just wait until I throw in the S4C as the YS1 feels pretty much fine.

Is there a particular weight you'd recommend? Isn't most other MTF really thick in comparison to 10w-30 and/or Honda MTF (I mean you said it's rather thin though)? Obviously no friction modifier needed for stock diffs.

I'm going to have to start with the Honda MTF either way, I paid for it; but I don't mind doing a fluid change shortly after installing the trans anyway, couldn't hurt.

I was curious too, I saw in a teardown that there's a magnet in the trans? no way to easily access that without taking the case off eh? would be nice to inspect/clean the magnet on a fluid change. I always like using magnetic drain plugs in my oil pan.

 

Just checking back on this thread. That is a lot of questions in several posts.

Viscous was never available in the US. Viscous is subpar IMO.

High RPM in regard to Honda MTF is over 4,000. Use Torco MTF or RTF (click link in signature).

 

Cool, yeah I heard the Honda MTF changed so.. I'll run it for the first bit because it's what I have but I'll swap it out with your recommendation shortly.

Most posts I've read do say the viscous is worse. It was supposedly definitely built with USDM parts. The guy who had it built was a parts manager for Acura or something so.

Can't wait to drop it in. My innovative cable adapter finally arrived today and the mount came saturday, using that until I can go full hydro.

PS: thanks for your wisdom, merry christmas