S4 GXL LSD, confirmation

sv51macross · 01-07-2011, 11:32 AM

May have a lead on a S4 clutchie-LSD. Guy is local, and I want to make sure the pumpkin actually has a LSD inside it.

Question is, I don't know how a clutch-type unit behaves at rest. By turning/holding combinations of the input/output stubs, can I tell if there's a functioning LSD inside?

N.RotaryTech · 01-07-2011, 12:08 PM

I know that mine has a tag on it, located around the drain plug or fill plug.
Look for that.

sv51macross · 01-07-2011, 12:28 PM

Quote:

Originally Posted by N.RotaryTech

I know that mine has a tag on it, located around the drain plug or fill plug.
Look for that.

A bit more detail please.

N.RotaryTech · 01-07-2011, 04:31 PM

sv51macross · 01-07-2011, 04:38 PM

Quote:

Originally Posted by N.RotaryTech

Good enough for me. Yeah, I remember from my auto classes at CC clutchies take special diff oil.

[EDIT]: Ah, if the tag is missing, is there a mechanical way to tell if it's a LDS without cracking the pumpkin?

RETed · 01-08-2011, 02:09 AM

Spin one side...
If the other side spins the same way, then there's some kinda locker in it.
If the other side spins the opposite way, it's open diff.

Now, this doesn't confirm if the LSD is in good, working condition...
It could be loose and out-of-spec, which basically means it reacts like an open diff when pushed hard.
There are friction plates that do wear down internally.
High mileage usually means worn LSD...

-Ted

sv51macross · 01-08-2011, 04:07 AM

Quote:

Originally Posted by RETed

Spin one side...
If the other side spins the same way, then there's some kinda locker in it.
If the other side spins the opposite way, it's open diff.

Now, this doesn't confirm if the LSD is in good, working condition...
It could be loose and out-of-spec, which basically means it reacts like an open diff when pushed hard.
There are friction plates that do wear down internally.
High mileage usually means worn LSD...

-Ted

So, if I go to the local Mazda dealer, how much will they rape me, er, charge me, for replacement friction discs?

RETed · 01-08-2011, 05:05 AM

I doubt any Mazda dealer would do the labor for it.

Looking at the Mazdatrix website:
http://www.mazdatrix.com/G8LSD.HTM

It looks like they charge around $350 just for the discs.

Find a good drivetrain shop locally, and they can do the work for you.
Assuming the prices from Mazdatrix, a fully rebuilt diff is going to cost you around $500 - $700 for parts and labor.

-Ted

01-07-2011, 11:32 AM	#1
sv51macross Rotary Fan in Training Join Date: Oct 2010 Location: Ann Arbor, Mi Posts: 47 Rep Power: 0	S4 GXL LSD, confirmation May have a lead on a S4 clutchie-LSD. Guy is local, and I want to make sure the pumpkin actually has a LSD inside it. Question is, I don't know how a clutch-type unit behaves at rest. By turning/holding combinations of the input/output stubs, can I tell if there's a functioning LSD inside? __________________ 1990 Mazda RX-7 NA; Lucy, after the main antagonist from Elfin Lied. Eventual plans? Something cyberpunk and spicy.

01-07-2011, 12:08 PM	#2
N.RotaryTech Home-brew Rotary Join Date: Feb 2008 Location: GooseCreek SC Posts: 552 Rep Power: 18	I know that mine has a tag on it, located around the drain plug or fill plug. Look for that. __________________ '89 RX7 GTU, half-Bridge-port S4/S5 NA, E6K, Full RB exhaust, weekend warrior. '83 RX7, The "this might take awhile" project. '87 RX7 GXL, Rest In Pieces. '98 Subaru Impreza Outback-sport, rx7 rescue vehicle, down for repair. '94 Ford Ranger, daily.

01-07-2011, 04:31 PM	#4
N.RotaryTech Home-brew Rotary Join Date: Feb 2008 Location: GooseCreek SC Posts: 552 Rep Power: 18