915 LSD Diff Question

John Lussier · John Lussier's Garage

I'm trying to find an LSD that will work with my 915 euro transmission that has the factory oil cooler. Guard Transmission has an extremely expensive solution, but beyond that, I've not had any luck in finding a unit that will work.

Besides converting the transmission to a non-cooler unit, which I'd rather not do, has anyone found an LSD diff that works?

Thanks,

John

JeremyD · JeremyD's Garage

factory LSD? The turbo version works also that fits the 930 box

KTL · 01-18-2012, 05:38 AM

Yep. A plain 'ol factory LSD will suit you just fine. The euro trans cooler has nothing special, in terms of the diff itself, that prevents you from using the typical factory LSD housing. That said, any other diff will work as well. Guard, Quaife, OS Giken, OBX (careful....), Kaaz (careful...) Wavetrac, and of course original Porsche.

Here's one from DC auto Fine spline 915 lsd diffs 4sale

there's a 930/911, Wavetrac, OBX and Kaaz on ebay right now. Check 'em out.

John Lussier · John Lussier's Garage

Kevin,

The spool has to accomodate the oil pump ring gear and none of the after market units you mention except for the Guard unit do....at a cost of 3k plus shipping it still doesn't fit if you get my drift.

I did chase down the unit that DC Auto has for sale and it is for a non-cooler app and does not have the needed mounting bosses for the oil pump ring gear. Haven't been able to locate a factory LSD for the cooler equipt trans and not so sure I will.

John

Bill Verburg · Bill Verburg's Garage

You'll need any lsd from a '84-86 915. These will all have the bolt holes to mount the pump gear
915.332.053.21
pump drive gear

mounted

alternately a machine shop can drill 2 threaded holes for you in an older lsd.

John Lussier · John Lussier's Garage

Bill,

I hear you...that is the same part number on the unit listed at DC Auto. We sent Mike at DCA pictures of the stock spool, etc and his come back was no. Don't know if he wants to sell it or not as he went into a rant about worth more in rebuilt tranny, etc????

I'm going to "try" and buy it from him and deal with the machining as necessary.

Thanks for the confirmation,

John

KTL · 01-19-2012, 06:23 AM

My thought was what Bill posted. The bolt holes are just drilled and tapped so a competent machine shop should be able to center the pump gear on the diff body and place the holes for you.

Matt Monson · 01-19-2012, 09:46 AM

Quote:

Originally Posted by KTL

That said, any other diff will work as well. Guard, Quaife, OS Giken, OBX (careful....), Kaaz (careful...) Wavetrac

So you are saying that all of the differentials on that list have the holes drilled in them to mount the factory oil pump drive gear? Or are you saying that every differential on that list could be modified to accomodate the drive gear?

KTL · 01-19-2012, 10:30 AM

No way any of the non-OEMs, besides yours, are going to make a provision for something as unique as the gear oil pump. Heck, I wouldn't be surprised if any of those others don't have a provision for the speedo magnet ring!

Looks tight on the Quafie but I believe the holes could be oriented to accept the ring around the bolted case area. OSG, Kazz, OBX have clear area behind the ring gear flange to mount. Wavetrac, I take back that statement, as the bolt spacing on their case is very tight.

The depth of the case behind the ring gear obviously varies from one make to another. The critical dimension from their manufacturing perspective is the seat for the side bearing. Beyond that, they can make the case whatever shape suits their needs. However, given the simple nature of the mounting, a suitable spacer could be made to "shim" the depth of the oil pump gear

Matt Monson · 01-19-2012, 11:04 AM

Ok, just checking. For a minute there I thought I was behind the curve on the competition's product development and current offerings...

John Lussier · John Lussier's Garage

Matt,

Hands down, you have great products and I would love to install it in my trans, but my finances dictate otherwise. I understand and appreciate quality offerings and in a few years (or a couple of corners) I maybe saying, damn, I should have gone for it .

John

Matt Monson · 01-20-2012, 08:25 AM

Quote:

Originally Posted by John Lussier

Matt,

Hands down, you have great products and I would love to install it in my trans, but my finances dictate otherwise. I understand and appreciate quality offerings and in a few years (or a couple of corners) I maybe saying, damn, I should have gone for it .

John

John,
Thank you for the compliments. And I totally understand the finances thing. I'd love to covnert my 3.2 to a Gamroth 3.4l with slidevalves and it's just not in my budget, especially with a 2 month old in the home now. My mod money just dried up for a couple of years.

I generally try to steer clear of these sorts of threads because I don't want to appear to be pushing my product on you guys. I attempt to keep my participation on Pelican primarily technical, in the spirit of the vendor-free environment that Wayne has so graciously created here. I just asked the questions to make sure that all the information was clear. I wasn't sure what Kevin was saying so asked for clarity, otherwise I would have just skipped the thread and left you to the guidance of your peers.

Regards,

Matt