Hello List - As you might recall, there was a lengthy flurry of messages regarding failures of input and main transmission shafts. I took a good look at the reports, and have decided to do something about what appears to be the primary failure mode in this area - the splined coupler that connects the input shaft to the main shaft. I have focused in on two components; the coupler itself, and the roll pin that is used to fix the coupler to the main shaft. In a recent local failure, the coupler stripped out, and the roll pin sheared. The sharp fragment of the pin caused irreparable damage to the splines on the main shaft, resulting in the expensive replacement of the main shaft. The failed coupler is made from mild steel, possibly 4130 alloy, with a heat treat of about 115,000 PSI ultimate tensile strength (very soft). It is only partially splined internally (perhaps 50%). The theory has been proposed that this is supposed to be a "fuse" of sorts to protect the main shaft from damage. So far, not so good. The "protection" has become the primary failure of the transmission, which is not acceptable. I have commissioned custom couplers made from 4340 alloy at a heat treat of about 150,000 PSI ultimate tensile strength, and are fully splined for maximum strength. They are nearly done, fit the shaft splines better than stock, and are beautiful! I have also obtained a stronger variety of roll pin that is much more resistant to coming out prematurely, and also cracking. For those of you who are contemplating horsepower increases, or want a better load path into your transmission to avoid future expensive failures, I will have a limited number available by mid next week. Please contact me off-list for further information at toby(at)delorean-parts.com. We will have some available at PF, unless they are sold out immediately. See y'all there! Toby Peterson VIN 2248 "Winged1" DeLorean Parts Northwest, LLC www.delorean-parts.com To address comments privately to the moderating team, please address: moderators@xxxxxxxxxxx For more info on the list, tech articles, cars for sale see www.dmcnews.com To search the archives or view files, log in at http://groups.yahoo.com/group/dmcnews Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/dmcnews/ <*> To unsubscribe from this group, send an email to: dmcnews-unsubscribe@xxxxxxxxxxxxxxx <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/