Donor rear diffs

NiftySVX · #1 02-03-2014, 01:58 PM

Hello all, It looks like I am going to be replacing my level ten paperweight with a 3.70 ratio trans.

WHO KNOWS the specifics of the diff compatibility? If it has 5 bolts for the side plates will it work? I am having some trouble locating a 3.70 rear diff.

SVXfiles? Anyone?

92 SVX · #2 02-03-2014, 03:04 PM

I can understand wanting to stay auto but why not go 4.44 gears?

Tireiron · #3 02-03-2014, 03:18 PM

Where are you coming across a 3.70 in the US? There were almost no Subaru's built with 3.70 in this country. Almost exclusively limited to the 06/07 WRX manual.

Your best option aside from getting an overseas SVX 3.70 rear diff is to swap the r160 3.70 ring and pinion gear into your SVX r160. You cannot swap the WRX r160 in because the SVX axle shafts will not fit the WRX diff, and the WRX axle shafts will not fit the SVX rear knuckles. You maybe able to find a used diff to get the gears from, but if not you can still get them new from Subaru and I think ralli spec.

92 SVX · #4 02-03-2014, 03:22 PM

Quote:

Originally Posted by Tireiron

Where are you coming across a 3.70 in the US? There were almost no Subaru's built with 3.70 in this country. Almost exclusively limited to the 06/07 WRX manual.

Your best option aside from getting an overseas SVX 3.70 rear diff is to swap the r160 3.70 ring and pinion gear into your SVX r160. You cannot swap the WRX r160 in because the SVX axle shafts will not fit the WRX diff, and the WRX axle shafts will not fit the SVX rear knuckles. You maybe able to find a used diff to get the gears from, but if not you can still get them new from Subaru and I think ralli spec.

Actually thats not a bad idea, get the euro/jdm vtd trans and tcu and worse case get wrx 3.7 gears and swap into svx diff.

If I was thinking about staying auto that may be my plan.

NiftySVX · #5 02-03-2014, 03:40 PM

There were a ton of subarus made in the 80s with 3.70. I know I will have to swap the gears in. That's what I want to know.

I don't want to go to 4.44 because that is too tall of a gear for this car. I was considering 4.11 but 3.70 is easier because I can build a trans based on a FWD svx unit. I have three of them. Plus if I can get a VTD trans I can bolt it in.

Blacky · #6 02-03-2014, 05:44 PM

A 1980's tranny will not bolt up to an EG33 engine. 4.44 is a lower ratio than the stock diff. and is very well suited to the SVX engine. The 4.44 is also known to be much more durable than stock. 4.11 trannys are weak and fail often on an SVX.

NiftySVX · #7 02-03-2014, 05:54 PM

I am not talking about the transmissions. I am going to build the transmission. Trust me I'm an expert on the 4EAT. No matter what ratio I go with it will be the big daddy 4eat with 5 clutch plates.

I have a stack of these transmissions. I can put any gear I want in the transaxle. That isn't what I am talking about.

I do not want a 4.44 ratio. I don't want a gear that tall. I'm not interested in an SVX that is geared that tall.

What I need to know is if I can combine the 80s 3.70 R160 and the SVX 3.545 VLSD

92 SVX · #8 02-03-2014, 08:36 PM

if you want 3.7 gears why not just grab a wrx the years listed, then transfer just the gears into the svx diff. keeping the svx's vlsd and axles?

Tapani · #9 02-03-2014, 08:41 PM

Quote:

Originally Posted by NiftySVX

I do not want a 4.44 ratio. I don't want a gear that tall. I'm not interested in an SVX that is geared that tall.

What I need to know is if I can combine the 80s 3.70 R160 and the SVX 3.545 VLSD

Yes you can. I have done two. You may need to grind the casting a bit for the LSD to clear (assembly only). While your at it, why not throw in a Quaife Torsen in the rear and a Modena TBD in the front ;-)?

Tapani

NiftySVX · #10 02-03-2014, 08:57 PM

Because a WRX diff is going to cost me a lot more. I know I need to use the SVX axles. I will have to call my source and make sure it is a 5 bolt diff before I buy.

Tireiron · #11 02-03-2014, 10:20 PM

All r160 diffs use the same size gear sets, so just put the 3.70 gears into the SVX housing with the SVX carrier and LSD.

NiftySVX · #12 02-03-2014, 10:36 PM

Some aren't compatible. I Will just buy this unit and hope I can swap it and don't have to remove the pinion from the case since no one knows anymore…..

Tapani · #13 02-03-2014, 11:23 PM

Quote:

Originally Posted by NiftySVX

hope I can swap it and don't have to remove the pinion from the case since no one knows anymore…..

Just protect the pinion bearings with a rag when you grind the housing to clear the LSD. I tried to find a photo of the exact spot - no luck.

/T