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Question, how much better is an AOR compared to a 5R? Is it truly worth the cost over a 5r?
There are two changes made to the AOR transmission as installed in the Turbo S and final year Turbo when compared with earlier 944 Turbo transmissions. The first is that the input shaft (mainshaft) had the 1st and 2nd gears that are cast into it given a better hardening treatment. These gears tended to break with heavy usage. Forty years after the 944-series introduction, I am seeing a lot of input shafts come to me with material erosion at the root of these gears, in all 944 cars including the eight-valve, normally aspirated base model. Stuff wears out, ask a 911 owner with a 915 transmission who is replacing gear sets. The improved input shaft fits all the 944S, S2, and Turbo transmissions and is a prudent upgrade when rebuilding, and a "must" if there is tooth erosion.
The second change was to the limited slip differential. It received 2.50 mm thick clutch discs, replacing the earlier versions' 2.00 mm discs. The pressure rings were shaved 0.50 mm to match. The pinion shafts (cross shafts) in the LSD received a moly coating where those shafts ride on the pressure rings' ramps, and tend to wear. I have seen a few AOR LSDs that have moly coating on their spider gears' teeth, but very few. These parts can all be retrofitted to any 944-series LSD if you want the upgrade. For street-only driving or the occasional autocross, I don't think upgrading a non-AOR LSD with the later parts is worth doing. But if you plan to spend time on track, it's a good route to follow.
02-21-2023, 05:08 PM
