por944s2

I have a new 968 that the PO installed a GT LSD. Still working out the kinks so my track time is limited so far, but the car got stuck in a gravel parking lot with just one wheel was spinning. Does a diff need more pre-load or something before both wheels lock up?

Oddjob

Yeah, that doesn't sound right. Clutch discs would have to be worn out for it to spin one wheel like that.

Cheyenne

No visuals?

e9stibi

No easy visuals while it is installed. Jack up the rear and try to rotate a wheel and observe if the other side rotates, too. If this is not the case, it is shot. This is a pretty simple way of testing.

Nolan Santacruz

Thanks for the information

GTgears

Are you sure they installed and LSD and not a TBD instead? Many people ignorantly refer to TBDs as an LSD even though they are not. Quaife hasn't helped things be misleading the general public with their marketing campaign. Did you get reciepts with the car? If so, I can tell you what is in there just based on price.

For a TBD to lock it requires some resistance. If it is in a no traction or very low traction situation, it will act like it is open.

por944s2

It's a Guard LSD with Clutch Packs, not a Quaife Torque Biased POS I have in my S2 Firehawk that the PO thought would make the car easier to drive in paddock WO power steering, WTF? I will check the age and get back. Thx

JoeMag

I'd just call Matt over at Guards and see what he says...

GTgears

I manufacture both TBDs and LSDs. To be clear, when I said that many people are ignorant about the differences, I was not talking about you, but was referring to the previous owner. I was suggesting that maybe it had a TBD in it and he didn't know the difference, especially given Quaife's misleading marketing campaign. Just because I made the differential doesn't mean it automatically has clutch packs.

I've also encountered a couple of instances recently where people were told they had purchased one of my LSDs and something else got put in the car. I'm not kidding. Shops who are not my dealers are telling people that they can get my product and are putting TBDs and other companies' LSDs into cars.

But you sound pretty sure that it is an actual LSD. Jack up one rear wheel. Put a torque wrench on one of the lug nuts and post the breakaway torque. That will give me a pretty good idea of the condition of the unit.

Regards,

Matt Monson
Guard Transmission llc

por944s2

Matt, Per service order 1/16/2009, Precision Motor Sports Racing - Guard GT3 50/80 LTD Slip Diff, During installation the S1 and S2 Carrier Bearings were replaced and Mobil 1 75W-90 Gear Oil was installed. Should both wheels spin in gravel? Thank you for your quick response?

GTgears

Either both wheels should spin, or one wheel will spin and the other will give you drive without breaking traction. It really depends how bad the traction is. What shouldn't happen is one wheel spins and digs a hole and you don't go anywhere.

por944s2

It dug a hole. What's the next step?

winders

Maybe this:

GTgears

If the car was tracked frequently I could see it worn out in 3.5 years. Pro teams usually get 1 season out of them (80-100 hours). Club racers usually get 2-3 years, some more some less. Given the install date it might need to have it reclutched.

GTgears

Ps. I sure hope it isn't on the original oil. If the car is tracked that should have been changed years ago.

Furthermore Mobil 1 is NOT the same as Mobil Delvac. I personally think the Mobil 1 too slippery and it reduces the effectiveness if the LSD.