What's the smart play: 3.7 --> 3.9 swap or buy a Legacy LSD?

Forum for Subaru XT and/or XT6 owners

Moderators: Hocrest, Myxalplyx, Huck369, Moodybluesr, grossgary, john in KY, SUBBYRU89, austinXT6

What's the smart play: 3.7 --> 3.9 swap or buy a Legacy LSD?

Postby RhodyM20 on Wed Jan 25, 2017 2:41 pm

Hey guys.

Searched and read but can't quite figure this part out. I have an XT6 with the stick.

I've seen a lot written about the LSD options for these cars but there's one thing I can't get a clear sense of. I have a 3.7 LSD at home and understand I can fairly painlessly convert this to a 3.9 LSD.

However, what I'm wondering is this: for the price I can get for a 3.7 LSD with the Datsun guys, should I just flip that and buy a Legacy Turbo 3.9 VSLD?

I have a feeling I'm missing something about the Legacy unit that makes that conversion more complex than just plug and play...but maybe I'm not.

Any clarification appreciated.
1980 320/6; 1987 325is; 1981 'Yota Hiace; Sold: 1988 XT6
RhodyM20
 
Posts: 111
Joined: Tue Aug 02, 2016 12:54 pm

Re: What's the smart play: 3.7 --> 3.9 swap or buy a Legacy LSD?

Postby crazyhorse_001 on Thu Jan 26, 2017 12:14 am

As far as the diff goes i believe it should be plug and play. If not it shouldnt be an issue to swap the lsd chunk into the xt6 housing
Nought but by the grace of God
Don't run out of talent, grip, and road all at the same time
'88 XT GL FWD/5spd, Gunmetal Grey "Little Bit"
'91 XT6 FWD/4eat, Silver, lost the battle with the the rust monster
User avatar
crazyhorse_001
Veteran
 
Posts: 2479
Joined: Sat Jul 24, 2004 5:28 pm
Location: Greeneville TN

Re: What's the smart play: 3.7 --> 3.9 swap or buy a Legacy LSD?

Postby RhodyM20 on Thu Jan 26, 2017 8:28 am

Hmm. So, I guess it comes down to the fact that the 3.7 could put some money in my pocket. I, unfortunately, have to rely on a shop to do the work and it'd certainly be cheaper to just drop the exiting open diff and install the 3.9 from a Legacy.

Does anyone know if there are any issues with mounting the Legacy unit - are any extra parts needed for the XT6 to "accept" it?
1980 320/6; 1987 325is; 1981 'Yota Hiace; Sold: 1988 XT6
RhodyM20
 
Posts: 111
Joined: Tue Aug 02, 2016 12:54 pm

Re: What's the smart play: 3.7 --> 3.9 swap or buy a Legacy LSD?

Postby grossgary on Wed Feb 01, 2017 10:54 am

legacy are VLSD's wear out to an open differential anyway. higher dollar "LSD" prices for what will become (or might already be when you install it) an open diff.

you could put an offer out there to trade your 3.7 for a 3.9 or trade plus cash (since 3.9's are more desirable and the conversion requires new seals).
Gary
89 XT6, rear LSD
02 OBW VDC H6
06 Tribeca
grossgary
Moderator
 
Posts: 11634
Joined: Wed Jun 18, 2003 9:34 pm
Location: midatlantic

Re: What's the smart play: 3.7 --> 3.9 swap or buy a Legacy LSD?

Postby RhodyM20 on Wed Feb 01, 2017 3:46 pm

grossgary wrote:legacy are VLSD's wear out to an open differential anyway. higher dollar "LSD" prices for what will become (or might already be when you install it) an open diff.

you could put an offer out there to trade your 3.7 for a 3.9 or trade plus cash (since 3.9's are more desirable and the conversion requires new seals).


Fair point. I bought one for $150 that looks nice enough to be a factory replacement diff from a Legacy Sport sedan.

The 3.7 went on eBay and sold for the $300 Buy-It-Now. Should have asked for more, but it was a complete unknown condition-wise.
1980 320/6; 1987 325is; 1981 'Yota Hiace; Sold: 1988 XT6
RhodyM20
 
Posts: 111
Joined: Tue Aug 02, 2016 12:54 pm


Return to Subaru XT discussions

Who is online

Users browsing this forum: No registered users and 21 guests

cron