Jump to content
Ultimate Subaru Message Board

lsd swap q


Recommended Posts

im planning on taking the lsd/complete rear susp. from my 88 gl10 turbo and putting it in my 91 loyale wag this weekend. the rear end on my loyale is 3.9.

the lsd says 3.7.

 

the suspension on the loyale is trashed and the camber sucks so im planning on just unbolting the sedans rear susp/struts/lsd/axels/disc brakes as one unit and bolting it to my wagon.

 

 

Question the first: does it matter that im trying to put the sedan susp("tube" and everything) on a wagon? it looks the same but you never know til you know.....

 

Question the second: is putting a 3.7 in the place of a 3.9 going to cause issues?

 

Question the third: if there were to be an issue with swapping the aforementioned rear ends how can I fix it?

 

 

my thanx Rob

Link to comment
Share on other sites

i realize this is prolly a dumb question to ask, I have been searching for info for about an hour and a half now. If there is already a thread for this(im sure there is im just not finding it) can someone hook me up? Has anyone on here done the swap?

 

id like to not find out by breaking something on my dd

 

 

thanx Rob

Link to comment
Share on other sites

Can you swap the transmission too? If not, then mixing 3.9 and 3.7 would be really bad. 4wd mode would probably destroy everything. The WRX is the only car I know of that uses different front and rear ratios, and that transmission is built for it. You may be able to run in 2wd with minimal problems, but then, why would you swap in the first place, or even have a Subaru, for that matter?

 

Jacob

Link to comment
Share on other sites

thanx Jacob, I do have the tranny from the parts car but its a ft awd w/ center diff lock. im concerned with the drop in mpg that will come w/ powering all 4 all the time. also, my loyale does not have a center diff lock switch, not being able to lock isnt as big a concern as not knowing if that would be a problem. are there any threads on this?

 

 

Rob

Link to comment
Share on other sites

thanx Jacob, I do have the tranny from the parts car but its a ft awd w/ center diff lock. im concerned with the drop in mpg that will come w/ powering all 4 all the time. also, my loyale does not have a center diff lock switch, not being able to lock isnt as big a concern as not knowing if that would be a problem. are there any threads on this?

 

 

Rob

 

Yes there are. You'll have to search, though. Basically you need to change the LSD's ratio to match the transmission, or else it'll kerplode. Depending on what you want to use the car for, the full-time transmission may be worth swapping in.

 

Jacob

Link to comment
Share on other sites

cool beans. found Qmans post on the swap. again thanx for the wheels Ken, havent gotten the other two yet but with the gl10 parts car in the garage I havent got time for them anyway. thanx again Jacob, im glad i didnt explode my stuff.

Link to comment
Share on other sites

I honestly dont think its worth not changing the transmission too. Those are great transmissions, the AWD is fun year round and not having a binding situation on those half slippery pavement and half dry is nice. The mileage drop is not that significant and the 3.70 actually offsets part of it.

Link to comment
Share on other sites

ya i think ill be keeping the push-button 4wd, it doesnt look that hard to make the lsd swap happen. plus, when i get stuck in fwd, i can put the car in 4wd and usually(especially w/lsd) get unstuck. if i get stuck w/awd/lsd im stuck. no bueno.

 

 

Rob

Link to comment
Share on other sites

the 3.70 actually offsets part of it.

 

no, it doesn't. the turbo transmissions are geared differently, so despite the 3.70 axle ratios, you'd be turning higher rpm in 5th.

 

also, IMHO the FT4WD is awful. True AWD would be a drastic improvement, and worth the drop in mileage. But FT4WD is the worst of both worlds. I've put tens of thousands of miles on all 3 setups in many conditions (rally, ice racing, wheeling, daily driving, autocrossing), and will go out of my way to avoid FT4WD.

 

 

convert the LSD to 3.9, and be done with it. easier, and better. swapping the whole rear suspension isn't bad either, I've done it many times. and using a Turbo donor, you'll gain a rear sway bar, which really helps keep the car planted on the road.

Link to comment
Share on other sites

ya, i was thinking that a ratio of 3.7 would yield less gass milage than a 3.9 but im new to converting diffs and if i was going to do a tranny swap itll have to be a dual range for sure.

 

while ive got you on the "line" 'chux, could you clarify: my donor car is a sedan and my loyale is a wagon. im good right?

 

 

thanx man

 

Rob

Link to comment
Share on other sites

Please sign in to comment

You will be able to leave a comment after signing in



Sign In Now
 Share

×
×
  • Create New...