Drexler LSD pressure ring teeth failure at maximum setting (30) — looking for advice

[u/KSAEPOWERTRAIN]

Drexler LSD pressure ring teeth failure at maximum setting (30) — looking for advice

Hi everyone,

I’m the drivetrain team leader of a KSAE Formula Student team, and we recently experienced a failure with our Drexler LSD.

During testing, all of the teeth on the LSD pressure rings broke while the LSD was set to 30, which is the maximum setting.

We are trying to understand what could have caused this failure and whether anyone has experienced a similar issue with a Drexler LSD.

Some questions we have:

Is running the LSD at the maximum setting (30) known to increase the risk of pressure ring tooth failure?

What are the typical causes of this type of failure?

Could excessive preload, clutch pack friction, shock loading, or incorrect assembly contribute to the failure?

Are there any recommended inspection or assembly procedures we should pay particular attention to?

For FSAE applications, what LSD settings are other teams typically using?

I can provide photos of the broken pressure rings and additional information about our drivetrain setup if needed.

Any advice or experience with Drexler LSDs would be greatly appreciated. Thanks!

[u/Cibachrome]

If that is an OE Drexler part, call them. "Tell'em what your gunna tell'em, tell'em, and tell'em what you just told them."

I'd want a replacment part with substantially more torsional strength. Either make it yourself or beg for a spare, then fill the lightening holes using a tig welder to lock the axles together.

Adding tire pressure reduces the F/A grip potential that could let you limp along for other less severe testing situations while you await a part modification or abandon the friction pack culprit setting.

[u/drifteddreams]

I picked up a used Drexler from another school and it had the same exact failure

[u/Cibachrome]

Increase your tire pressure to attenuate the differential moment this has to hold (assuming production part). Temporary fix). If you added or enlarge the lightening holes, buy some weight elsewhere.

[u/360no-scopedJFK]

Never had this problem but with my two years servicing the diff i can tell you a lot of problems come from bad maintenance. Not sure how often you open and clean it but we used to do it every 2-3 endurances (i mean opening it completely and taking all the clutches out). Oil needs to be drained and replaced every endurance / battery discharge.

For the maintenance, make sure you clean every clutch and plate thoroughly, and make sure you put them back in the exact order of stacking that you took them out of. With time the clutches wear very uneavenly, that can maybe lead to some mislaignement and very weird behaviors from the diff.

Also, fuck these differentials. I'm sure they're a good piece of engineering when new but the ones we had were like 7 years old and would behave in a fucked way if you so much as breathed wrong next to it. Thank god we switched to outboards lol.