Shelby Posi Info/ LSD Options???

[glhs399]

I have tried searching around the forum and the net for info on the Shelby Posi unit but no luck. I'm sure someone on here know some info about them (Cliff...) I'm wondering what kind of lsd it was or what it was modified from. For some odd reason I have it stuck in my head that it was a modified dana 30 diff but I'm not sure at all....

Also, around a year ago or more some of the neon guys were talking about getting a clutch type lsd produced in the UK from Gripper. Did anything ever come out of that? Are there any new options out there for fwd turbo mopar trannys other than QUAIFE/OBX, Phantom Grip/The Blak Trax LSD? I'm still looking for a clutch type for my rally car. The main goal it to drive out of a stage if I break an axle. I've driven around with my GLHS with a welded 525 diff and love how it handles in the loose stuff but on the street it's no fun. Well, lets hear the options!

[Mario]

Some info I dug up:

".......two different units that the old Shelby Motorsports sold for our cars, and then there's the viscous ( I think Machinehead refers to is as a hydraulic locking) type that has been used in Jeeps as well.

The small Dana is a multi-disc clutch type torque sensing (that is, they work off the differences in torque transmitable to each side) unit, that SM sold for the 520 and 523/543/568 manual transaxles. I'm not sure how compatible these things are with ATF....somone should talk to Dana about using them with automatic transaxles.

The "jellybean" type is a classical cam and pawl torque sensing unit which was invented in the early part of the 20th century. Those "jellybeans" are actually called "pawls", though are sometimes colloqually referred to as "chicklets".

The hydraulic locking units are usually viscous couplings that are speed sensing (that is, they work off of the difference in speed from side to side), and a silicone goo that heats up due to the speed differences (from the side gears thru interlocking plates in the diff) and changes viscosity (aka fluid shear resistance) based on the amount of heat input. When the diff heats up to a certain point, the plates can lock together (aka "hump" mode), which is tough on the diff and trans because it's locking all the heat into the system, but works ok for off road applications where it's in an axle that's seperate from a transaxle, and can cool off quickly."

Per Cliff:

"When new they ran $1200 to $1500 depending on where you bought them. You can't buy them any longer, haven't for years and they are nothing like a Quaife or PG. They are a mechanical unit and were ONLY for the 460, 465 and 525."

Pics Per 1985ShlbyChrgr:



Pics Per Cliff Ramsdell:

[glhs399]

Thanks for the info!

[turbovanman²]

Nice find Mario,

[2.216VTurbo]

Way to go Mario I've never seen the exploded views of the Chicklett diffs. Weren't they built by "Saines" in Florida?

[TurboGLH]

Those pics were actually taken right before that unit was install in a transmission. As I recall it was a brand new unit still in the box. Very pretty unit, makes you kind of sad to see a set of bearings press on and it hidden away behind some steel and aluminum.

[Mario]

Those pics were actually taken right before that unit was install in a transmission. As I recall it was a brand new unit still in the box. Very pretty unit, makes you kind of sad to see a set of bearings press on and it hidden away behind some steel and aluminum.

I hope you don't mind that I posted them. I've had these saved on my comp for a long time and forgot to give credit to Cliff/Yourself.

[TurboGLH]

I hope you don't mind that I posted them. I've had these saved on my comp for a long time and forgot to give credit to Cliff/Yourself.

I'm guilty of the same thing, you never know when pics are going to drop off into the void so I keep copies of stuff that I think is important. On that note, the pics are my dads not mine, I was just adding some story to them. I don't think he would mind, besides anyone who's been to the shop would recognize those gorilla hands and/or the crappy brown work bench and know where they came from

[contraption22]

Just curious, what would be the advantage to this type of diff vs Quaife/Obx/Peloquin type

[1985ShlbyChrger]

Actually, the first 3 pictures at the top are mine. I took them a few years ago of pictures from a magazine, I also have a picture and explanation of the fiberries. All the pictures are on my photobucket account. I don't care if they're used, but I don't want them to be construed as someone elses.

Also, I'm not saying anyone stole them, I just want it to be known that I took them. That is all.

[Mario]

Photos credited.

[Cliff Ramsdell]

Yeah but I loved that old bench. It took so much abuse and lasted 14 years at the old place and yes, those are my meat hooks.

As for the question about the 525 cam & Pawl. Shelby built these to cheat, plain and simple.

No posi unit was allowed and this unit act's like an open diff when doing inspection, car in neutral, one wheel jacked up and it spins. This was the test and a clutch unit would have either been very tight or would not have turned.

This will lock both tires when power is put to the unit, it's hard to explain in test, a video is really needed to show how it works.

There was a Quaife stile unit for the 525 at one time also but I forgot who made it, had one hear some years ago also but it was fragile and broke quickly, the cam & pawl takes a good beating.

Cliff Ramsdell
The Transmission Authority
For all your 5 speed and 3 speed auto needs
Mopartek@aol.com
'86 GLHS 210 Shelby Roll cage and Posi unit. http://www.members.aol.com/mopartek/home.html
www.Mopartek.com

anyone who's been to the shop would recognize those gorilla hands and/or the crappy brown work bench and know where they came from

[2.216VTurbo]

Yeah but I loved that old bench. It took so much abuse and lasted 14 years at the old place and yes, those are my meat hooks.

As for the question about the 525 cam & Pawl. Shelby built these to cheat, plain and simple.

No posi unit was allowed and this unit act's like an open diff when doing inspection, car in neutral, one wheel jacked up and it spins. This was the test and a clutch unit would have either been very tight or would not have turned.

This will lock both tires when power is put to the unit, it's hard to explain in test, a video is really needed to show how it works.

There was a Quaife stile unit for the 525 at one time also but I forgot who made it, had one hear some years ago also but it was fragile and broke quickly, the cam & pawl takes a good beating.

Cliff Ramsdell
The Transmission Authority
For all your 5 speed and 3 speed auto needs
Mopartek@aol.com
'86 GLHS 210 Shelby Roll cage and Posi unit. http://www.members.aol.com/mopartek/home.html
www.Mopartek.com

Shelby Cheat??? Surely you dont mean that Cliff ...

Tim P told me that those Shelby Chargers he ran in the IMSA series had double firewalls. Nice to be able to 'order up' a car that way

[johnl]

Alan, you may recall that I got a cam & pawl unit from Boyd (he got it from Dave) and then shipped it to Cliff and he built it into the 525 hybrid that is in my 85 GLHT. As I recall, the floating pieces looked more like peanuts and less like chiklets though.