Tranny Forensics

Several weeks have passed since our disastrous race weekend, and our fury has worn off to the point where we feel like investigating...  I wouldn't blame you if you didn't believe Murilee Martin's trackside postings about our transmission failing "while backing out of the pit space."   Unfortunately that was only partially untrue.  Turns out that we did our transmission in while towing it to the event...

Disassembly of the transmission revealed the nice smeared-metal-rounded-ash-tray-kind-of thingy you see above.  That's the input shaft where a bearing's supposed to fit snugly.  And below is the output shaft where that same bearing is supposed to ride on a nice cylindrical shaft.



Yes, it's that rounded chunky-nipple-looking protrusion that's supposed to be cylindrical.  And precision.  And not effed up.

Turns out that the assembly lube that our man used to rebuild our transmission was wax-based.  When the tranny heats up in the slightest, the wax melts away to be replaced by the tranny fluid (Dextron-IV in a Ford T5) which sloshes around in the case.  Problem was, we didn't have a chance to drive the car at all before towing it to the race.  On a dolly.  Ever heard the recommendation that if you're dollying a rear-wheel drive car, disconnect the drive shaft first?  Heed it.

So the output shaft, which sits in the top of the case, spun furiously with the rear wheels while the intermediate shaft sitting all cozy and wet in the bottom of the case didn't.  And thus no fluid flung around to replace the melting wax-based assembly lube, which probably only lubricated the bearing and the shafts pictured above for a mile or so.  Kershaw is a bit further from Atlanta than that.