[eschaider]

Thank you for the kind words but with all due respect I don't think there is a sufficient market available to recoup the development costs for a venture like this which is possibly why manufacturers have not offered a replacement part. Other than yourself it appears you can count the number of potential customers by counting fingers on one hand.

You should be able to hit 70 mph in third gear by 4000 rpm or so and nearly 100 in fourth by 4500 rpm. The car's acceleration will always be greater in either third or fourth gear at these speeds than it is in overdrive. This again begs the question why are we power shifting into a slower accelerating gear at a point in time when we are attempting to increase vehicle speed to match traffic?

I think your breakage problem would disappear if you used the overdrive feature of the transmission as an overdrive to minimize engine speed at highway speeds. If you continue to use 5th gear overdrive to accelerate the vehicle to traffic speeds rather than using third or fourth gear, you are going to continue to experience component failures.

The overdrive feature on any of the currently available transmissions is meant solely to reduce engine rpm at highway speeds for better fuel economy or reduced engine noise. Using it to provide acceleration rather than a lower gear will always produce a reduction in life for one or more of the overdrive components.

The overdrive components in the transmission can not provide the mechanical advantage to the engine a lower gear ratio can. More importantly the difference in under drive to over drive gear ratios strains parts of the transmission that were not engineered for that kind of loading when used for acceleration.

I think you will find relief from the parts breakage if you change your driving style. Of course you don't have to but a continued use of 5th gear overdrive will likely produce a continued trail of broken parts. Even if the modifications you are contemplating for the current parts failure succeed (which I suspect they would) you would just begin breaking the next most vulnerable part in the overdrive section of the transmission.

Perhaps most significantly your desire to merge with existing vehicles at the speed they are traveling would be much easier to achieve using third and fourth gears as you enter the highway. Once up to traffic speed you can always normally shift into overdrive to reduce engine speed and noise at that vehicle speed.


Ed