KMS Differential Questions

[CompClassics]

TIC TOC, your differential may be a time bomb!
The problem with the differential oil leaks on CSX Continuation Cobras and others that utilize the Kirkham Motorsports aluminum differential with the billet aluminum differential cover can stem from the way Shelby American and or whomever assembled the Continuation Series Cobras prior to delivery to the purchaser. After talking with David Kirkham about a differential oil leak issue that I had with a clients 6000 Series Cobra David asked me how the differential breather was installed on my clients car, I told him David then informed me that his billet differential cover did not have a breather oil deflector built into it and that if the differential breather was vented from this position that the differential would pump the oil out of the differential while the car was in motion, this is definitely NOT good for the differential! THE DIFFERENTIAL REQUIRES A PREDETERMINED AMOUNT OF OIL IN IT TO PROPERLY LUBRICATE THE BEARINGS AND GEAR FACES PROPERLY, if any amount of gear oil is being removed from the differential during operation it will ultimately damage the differential through lack of lubrication. I’ll call this next discussion “Tic Toc”, the reason I call this “Tic Toc” is because of the way the Continuation Cobras were setup by the manufacturer, albeit disregarding David Kirkham’s differential venting instructions. As before whoever installed the differential breathers on the Continuation Cobras utilized the fitting on the differential cover, remember the one without the oil deflector, and connected it via a rubber hose to the bottom fitting on a pint sized brake reservoir can, here’s where the “Tic Toc” comes in. Your differential starts off with the proper oil capacity, filled to just below the fill plug hole. You’ve just filled your fuel tank and you decide to go on a drive say 100 miles through the back country, not stop lights, no traffic, just a great day to go for a drive. Unaware to you the driver, the guy that just spent $130K + for your new toy, the differential is pumping the differential oil from your differential into that pint sized container which quickly overflows and spills out onto the ground and whatever doesn’t spill out is now trapped in that pint sized container until you come to a stop for a period of time. Remember as long as you are moving the oil is being pumped OUT of the differential, when you stop whatever oil is in the container returns back to the differential or at least that’s the manufacturers theory. Remember the amount of oil that escaped from the pint sized container will never make its way back to the differential. So how many times “Tic Toc” do you think this process of driving and stopping needs to happen before the differential is damaged? Remember EVERY time you drive the differential oil is pumped out. While talking to David Kirkham about the issue he said that it takes very little fluid loss before damage starts occurring. I believe David as my clients car traveled less than 1500 miles before all the bearings and the ring and pinion needed to be replaced. When driving roughly 100 miles the differential will loose more than one pint of oil. David Kirkham instructed the manufacturer that the breather should be routed to to the breather port at the top front of the differential near the pinion and that the port on the differential cover was for the oil cooler return hose. That makes sense as the oil cooler return hose would have enough pressure to overcome the pumping action of the ring gear. So who should be responsible for how the manufacturer assembled their product, the purchaser or the manufacturer who failed to follow the component manufacturers installation instructions? If you are a CSX Continuation Cobra owner check how your differential breather system is configured before you are looking at an expensive or possibly deadly consequences should your differential lock up while driving.

In the photos that are provided by the original poster of this topic it appears that the differential breather is installed on the incorrect differential port, the billet differential cover port.