Originally Posted By: JMHC
Too arrogant? You know, high end manufacturers like Mercedes are using this same design...automatically shifted manuals. That's how you can get these 7 speed transmissions. Ever try to get 7 gears out of a planetary gearset? Do you know that the automatically shifted manual is a lot lighter? It's a superior design if anything...
Now so why did they have failure issues? Well, when Honda came out with this design (derived from Indy cars, by the way) the transmissions shifted very sharply. This was great for the transmissions, but people complained. They were used to the typical slush box. So Honda incorporated these clutch packs that softened the engagement to please the average American car buyer. Well, they didn't get that right the first time. Then when they went to the 5-speed design, they added a third shaft just like all 5 speed manuals have over 4 speed 2-shaft designs. They missed the extra lubrication required, hence the Accord 03-04 failures cured by the extra trans fluid jet.
All of this obsession on here over Honda autos and how horrible Z1 fluid is clearly is total bogus. The clutch packs they used in the late 90's early 00's to make them smoother needed refinement, and the third shaft in '03 needed some lube. You can change your trans fluid every week, use Amsoil, whatever and it won't fix those problems. Just drain and fill with Z1 every 30K and it will be fine. If it fails, it wasn't due to the fluid.
IIRC it was Honda that didn't want to pay royalties to companies like Borg-Warner for a planetary based transmission design.
Honda's 5 and 6 speed manuals use two shafts. One mainshaft, and one countershaft. The countershaft drives the ring gear on the diff directly.
The '01-'03 5 speed autos had issues with clutch steel surface finish, as well as insufficient cooling, especially third gear. The '97-'99 models had issues with friction design and slippage during shifting tearing up the fluid.
7 speeds has been done for years with a planetary design, and ZF has an 8 speed unit out now.
Most manually shifted autos are planetary designs with electronic control over the valve body.
Some manufacturers have adopted hydraulic or electric actuators to shift conventional manual transmissions. Porsche, Ferrari, and the Toyota MR2 come to mind....
Honda 4 speed autos have three shafts too....
1997 to 1999 Acura 3.0 CL or 1998 to 2000 Accord:
The oil grooves are so large it leaves precious little friction area for a 200 hp+ engine.
